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1982 Dinocyst Biostratigraphy of Seymour Island, Palmer Peninsula, Antarctica. (Volumes I and II). John Harry Wrenn Louisiana State University and Agricultural & Mechanical College
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Recommended Citation Wrenn, John Harry, "Dinocyst Biostratigraphy of Seymour Island, Palmer Peninsula, Antarctica. (Volumes I and II)." (1982). LSU Historical Dissertations and Theses. 3781. https://digitalcommons.lsu.edu/gradschool_disstheses/3781
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International 300 N.Zaeb Road Ann Arbor, Ml 48106 8229524
Wrenn, John Harry
DINOCYST BIOSTRATIGRAPHY OF SEYMOUR ISLAND, PALMER PENINSULA, ANTARCTICA. (VOLUMES I AND II)
The Louisiana State University and Agricultural and Mechanical PH.D. Col 1982
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University Microfilms International Dinocyst Biostratigraphy of Seymour Island, Palmer Peninsula, Antarctica
Volume 1
A Dissertation
Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy
in
The Department of Geology
by John Harry Wrenn A.S. William Rainey Harper College, 1972 B.S. Northern Illinois University, 1974 M.S. Northern Illinois University, 1977 August, 1982 Dedication
This work is dedicated to my best friend,
Allison, my wife.
(She made me say that!) ACKNOWLEDGMENTS
I thank George F. Hart, my advisor, for his direction and constant sup port during this investigation. Sincere thanks is extended to the mem bers of my dissertation committee, Drs. James M. Coleman, Clyde H.
Moore, Judith A. Schiebout, and Willem A. Van den Bold, for their con sideration and constructive criticism. Evan J. Kidson was kind enough to review my taxonomic determinations and provide many suggestions which improved the final report; I thank him for his time and effort. 1 thank
Lewis E. Stover for his comments and for facilitating the preparation of some samples at the Exxon Production Research Company. Thanks are extended to Edde Griffin and Paco Ricalo for preparing the palynological slides at Exxon Production Research Company. 1 thank Peter N. Webb and the National Science Foundation Office of Polar Programs for providing the samples from Seymour Island and partial financial assistance to con duct this investigation. (Funds were provided from the National Science
Foundation Grant DPP79-07043, directed by Peter N. Webb.) I wish to thank Rosemary A. Askin and Scott W. Beckman for their assistance during my research. Many others, too numerous to name, provided helpful com ments for which I am grateful. The support provided by the Department of Geology (LSU), the Cartographic Section (LSU), and the Amoco Produc tion Company (Research Center, Tulsa, Oklahoma) is gratefully acknow ledged. Special thanks are tendered to Charles F. Upshaw and
Richard W. Hedlund for their support, consideration, and patience. Par ticular thanks are extended to Karen S. Bushyhead for typing the many drafts of this manuscript. I wish to thank everyone who has assisted in the production of
Appendix D (Dinocyst Descriptive Manual) and in particular
Richard W. Aurisano, John H. Bair, Scott V. Beckman, Richard W. Hedlund, and Evan J. Kidson for their critical readings of the manuscript.
Thomas T. LeFebre and James Kennedy, Jr. are responsible for the artwork and photography, respectively. Special thanks is extended to the Amoco
Production Company for its support and to Karen S. Bushyead and
J. Maxine Kirkham of Amoco Production Company for typing the various drafts of this manual.
Finally, hut not lastly, I thank my wife, Allison K. Wrenn, for her unflagging support and encouragement during the execution of this inves tigation. CONTENTS VOLUME I
Page
ACKNOWLEDGMENTS...... iii
LIST OF TAB L E S ...... vii
LIST OF TEXT F I G U R E S ...... ix
LIST OF PLA T E S ...... xiii
ABSTRACT ...... xiv
INTRODUCTION ...... 1 General statement ...... 1 Scope of this i n v e s t i g a t i o n ...... 1
SEYMOUR ISLAND ...... 3 Location and physiography ...... 3 History of exploration ...... 7 Geologic setting ...... 9 Stratigraphy ...... 10 Paleoenvironmental setting ...... 15
PALEONTOLOGIC BACKGROUND ...... 18 Previous paleontologic investigations on Seymour Island . . . 18 Palaeogene Period palynological studies pertinent to Seymour Island ...... 22 Maceral analysis ...... 23 Maceral and TOC analyses related to source rock analysis . . . 28
RESULTS OF THE GENERAL LITH0L0GIC EXAMINATION ...... 34
RESULTS OF THE PALYNOLOGICAL INVESTIGATION ...... 41 General statement ...... 41 General palynology of the sections ...... 46 The distribution of reworked palynomorphs...... 71
RESULTS OF THE MACERAL AND TOC A N A L Y S E S ...... 79 General statement ...... 79 General maceral and TOC analyses of the sections...... 79
INTERPRETATIONS ...... 100 Age determinations...... 100 Reworked palynomorph distribution related to the regional g e o l o g y ...... 122 Paleoenvironmental analysis ...... 125 Comparison of the Seymour Island and high southern latitude floras ...... 131 Source rock analysis...... 135
v CONCLUSIONS...... 140
INDEX OF MICROPLANKTON ...... 148
REFERENCES ...... 153
VOLUME II
Appendix A - Systematic Descriptions ...... 173
Appendix B - Sample Material and Preparation ...... 292
Appendix C - Data ...... 298
Appendix D - Dinocyst Descriptive Manual ...... 317
V i t a e ...... 465
vi LIST OF TABLES
Table Page
1. The microplankton recovered, by section, from Seymour I s l a n d ...... 43
2. Distribution table of microplankton, spores, pollen, macerals, and TOC in Section 3 ...... *
3. Distribution table of microplankton, spores, pollen, macerals, and TOC in Section 12-13 ...... *
4. Distribution table of microplankton, spores, pollen, macerals, and TOC in Sections 15 and 1 6 ...... *
5. Distribution table of microplankton, spores, pollen, macerals, and TOC in Sections 17, 18, and 1 9 ...... *
6. Dinocyst range chart arranged by the stratigraphic top of each species in Section 3 ...... *
7. Dinocyst range chart arranged by the stratigraphic top of each species in Section 1 2 - 1 3 ...... *
8. Dinocyst range chart arranged by the stratigraphic top of each species in Sections 15' and 1 6 ...... *
9. Dinocyst range chart arranged by the stratigraphic top of each species in Sections 17, 18, and 19 ...... *
10. Dinocyst range chart of species arranged by the stratigraphic base of each species in Section 3 ...... _ *
^ " 11. Dinocyst range chart of species arranged by the" stratigraphic base of each species in Section 12-13 ...... *
12. Dinocyst range chart of species arranged by the strati graphic base of each species in Sections 15 and 1 6 ...... *
13. Dinocyst range chart of species arranged by the strati graphic base of each species in Sections 17, 18, and 19 . . . *
14. Reworked palynomorphs recovered from Section 3 ...... 75
15. Reworked palynomorphs recovered from Sections 17, 18, and 1 9 ...... 77
* - This table is contained in the pocket at the rear of Volume II.
vii 16. The stratigraphically significant taxa recovered in Section 3 ...... 101
17. The stratigraphically significant taxa recovered from Sections 17, 18, and 1 9 ...... 110
18. The stratigraphically significant taxa recovered from Section 12-13 ...... 114
19. The stratigraphically significant taxa recovered from Sections 15 and 1 6 ...... 118
20. DinocyBts belonging to the transantarctic flora ...... 134
21. Palynological sample preparation procedure ...... 295
22. Total organic carbon sample preparation procedure ...... 297
23. Summary of the major orientation criteria and the orientation directions which they can be used to determine...... 332
viii LIST OF TEXT FIGURES
Text-figure Page
1. Hap of Antarctica showing the general location of Seymour Island ...... 4
2. Map of the northern Antarctic Peninsula and the James Ross Island Group showing the location of Seymour Island . 5
3. Map of Seymour Island showing the location of geographic features ...... 6
4. Stratigraphic columns of the La Meseta and Cross Valley Formations and a geologic location map ...... 13
5. Generalized depositional model for the major lithologic units on Seymour Island ...... 16
6. Comparison of the stratigraphic unit names and ages assigned to the Lower Tertiary deposits on Seymour I s l a n d ...... 19
7. The compositional continuum of sedimentary rocks based upon relative amounts of organic and inorganic constituents ...... 24
8. The classification of organic matter in sedimentary deposits ...... 24
9. A maceral counting sheet ...... 27
10. A comparison of the kerogen and maceral types depicting the types of hydrocarbons each would generate ...... 30
11. Van Krevelen type diagram depicting the point at which hydrocarbons begin to be generated by the various kerogen types ...... 31
12. Diagram showing the relationships between depth of burial, paleotemperature, vitrinite reflectance level, miospore color, thermal maturation, and hydrocarbon generation...... 33
13. Sediment grain size distribution in Section 3 35
14. Sediment grain size distribution in Section 12-13 .... 37
15. Sediment grain size distribution in Sections 15 and 16 . . 38
ix 16. Sediment grain size distribution in Sections 17, 18, and 1 9 ...... 40
17. Dinocyst species diversity and dominance in Section 3 . . 48
18. Dinocyst species diversity in Section 3 plotted against sediment grain s i z e ...... 49
19. Distribution of dinocyst types in Section 3 51
20. Distribution of spores and pollen in Section 3 ...... 53
21. Distribution of dinocyst types in Section 12-13...... 56
22. Spores and pollen distribution in Section 12-13 58
23. Dinocyst species diversity and dominance in Sections 15 and 1 6 ...... 59
24. Dinocyst species diversity and dominance plotted against sediment grain size for Sections 15 and 16 ...... 61
25. Types of dinocyst species in Sections 15 and 1 6 ...... 62
26. Dinocyst types present in Sections 15 and 16, plotted against sediment grain size ...... 63
27. The distribution of spores and pollen in Sections 15 and 15 ...... 64
28. The distribution of spores and saccate pollen plotted V against sediment grain size for Sections 15 and 16 ... . 65
v 29. Dinocyst species diversity and dominance in Sections 17, 18, and 1 9 ...... 68
30. Dinocyst species diversity and dominance plotted against sediment grain size in Sections 17, 18, and 1 9 ...... 69
31. Dinocyst types present in Sections 17, 18, and 19 . . . . 70
32. Dinocyst types plotted against grain size in Sections 17, 18, and 1 9 ...... 72
33. Spore and pollen distribution in Sections 17, 18, and 19 . . 73
34. Distribution of'macerals in Section 3 ...... 80
35. The distribution of 'inertinite in Section 3 ...... 83
>
X The percent inertinite plotted against sediment grain size in Section 3 ...... 84
Macerals distribution in Section 12-13 ...... 85
Distribution of phytoclasts plotted against sediment grain size in Section 12-13 ...... 86
Percent TOC plotted against sediment grain size in Section 12-13 ...... 88
The distribution of macerals in Sections 15 and 16 . . . . 89
The distribution of phytoclasts and protistoclasts in Sections 15 and 16, plotted against sediment grain size 90
The distribution of inertinite in Sections 15 and 16, plotted against sediment grain size ...... 92
Percent inertinite related to sediment grain size in Sections 15 and 16 ...... 93
The macerals present in Sections 17, 18, and 19 ...... 94
Phytoclasts and protistoclasts plotted against sediment grain size in Sections 17, 18, and 19 ...... 95
Percent All macerals and inertinite plotted against sediment grain size in Sections 17, 18, and 19 ...... 97
The distribution of inertinite in Sections 17, 18, and 19 ...... 98
Percent TOC plotted against sediment grain size in Sections 17, 18, and 1 9 ...... 99
The stratigraphic ranges of the stratigraphically significant taxa in Section 3 ...... 108
The stratigraphic ranges of the stratigraphically significant taxa in Sections 17, 18, and 19 ...... 112
The stratigraphic ranges of the stratigraphically significant taxa in Sections 15 and 16 ...... 121
Geologic map of Seymour Island ...... 123
The distribution of the transantarctic flora in the high southern latitudes ...... 136
Relative age relationships between the sections ...... 142
xi 55. The general depositional environments and depositional energy level represented by the Lower Tertiary sections . 144
56. Generalized map of the northeast corner of Seymour Island showing fault trends, the attitude of bedding planes, and the location of the cross sections depicted in text-figure 5 7 ...... 145
57. Topographic profiles and cross sections through northeast Seymour Island ...... 146
58. Hap depicting the locations of the stratigraphic sections on Seymour Island ...... 293
59. Location of the samples within the s e c t i o n s ...... 294
60. Generalized dinoflagellate illustrating the alphanumeric symbols, names, and relationships of thecal p l a t e s ...... 320
61. Fossil dinocyst exhibiting paraplate symbols, names, and relationships...... 322
62. Generalized peridinioid dinocyst illustrating morphologic features and directional terminology applicable to orientation ...... 326
63. Generalized dinocyst with an apical archeopyle depicting the orientation terminology applicable to this type of d i n o c y s t ...... 327
64. Specimen orientation and depth of focus related to apparent and real morphologic relationships ...... 334
65. Orientation flow chart for d i n o c y s t s ...... 339
xii LIST OF PLATES
Plate(s) Page
1-16. Illustrations of microplankton recovered from Seymour Island ...... 447
17-18. Examples of dinocysts depicting morphologic features useful for orientation ...... 463
xiii ABSTRACT
An investigation of organic-walled microplankton from the only known
outcrops of Lower Tertiary marine sediments on the Antarctic continent
has been completed. Seventy samples collected from seven stratigraphic
sections through the Paleogene Seymour Island deltaic complex were exam
ined. Forty-four dinocyst genera and 75 species were recovered, of which 2 genera and 10 species were new. Specimens attributable to the
Acritarcha, Pterospermatales, and Chlorococcales also were noted.
Dinocyst analysis indicated the sediments of the Cross Valley Formation,
in the Cape Wiman area, were laid down during the early late Paleocene
Epoch. The deposits at the type section in Cross Valley are biostrati-
graphically suspect due to known, but only partially mapped, faults in
the area; these sediments were deposited during the Paleocene-Eocene
epochs. The deposits of the La Meseta Formation were laid down during
the early Eocene and middle to late Eocene epochs.
Deposition occurred within the subenvironments of the various deltas which constitute the Seymour Island deltaic complex. Deposition
occurred within distributary channels, interdistributary bays, lagoons
and, perhaps, prodelta areas.
The dinocyst floras are composed of cosmopolitan and provincial taxa.
The former have been reported from regions as widely separated as Europe
and Australia. The provincial flora, previously named the transan
tarctic flora, was well developed in and around Antarctica by the Eocene
xiv Epoch. The distribution of the transantarctic flora suggests that a strait connecting the southwest Atlantic and southwest Pacific oceans existed during the Eocene Epoch.
Maceral and TOC analyses indicate potential hydrocarbon source rocks exist in the Seymour Island area. However, all of the samples studied are thermally immature or only entering early thermal maturity. More mature source rocks may lie below Seymour Island or in offshore areas.
xv INTRODUCTION
General Statement
Seymour Island lies in the Weddell Sea, near the northern end of the
Antarctic Peninsula. Two-thirds of the island consists of Cretaceous
System sedimentary deposits. The Lower Tertiary System sediments which crop out on the remaining third of Seymour Island constitute the only such exposures known from the Antarctic Continent. Previous palynolo gical studies of Seymour Island sediments indicated that rich Cretaceous
Period to ?Miocene Epoch dinocyst and spore-pollen assemblages were present (Cranwell, 1959, 1969a, b; Hall, 1977).
The uniqueness of the Lower Tertiary System marine deposits, the pres ence of rich palynofloras, and the geographic location of Seymour Island suggest palynological studies will reveal information unavailable any where else. It is expected that such studies will provide critical information about the distribution of Lower Tertiary Period palynomorph floras in the high southern latitudes.
Scope of This Investigation
The scope of this investigation is to:
1. document the dinocysts, acritarchs, macerals, and TOC concentra
tions present in the Lower Tertiary System,
2. establish a biostratigraphic framework for the Lower Tertiary
System of Seymour Island based upon dinocysts,
1 2
3. investigate the maceral and TOC spectra with regard to their
paleoenvironmental implications,
4. compare the dinocyst assemblages to other southern hemisphere
assemblages with regard to their paleogeographic and paleoceanic
implications.
Palynological analyses of the spores and pollen assemblages are being conducted by Dr. Rosemary A. Askins, at the Colorado School of Mines. SEYMOUR ISLAND
Location and Physiography
Seymour Island lies approximately 100 km southeast of the Antarctic Pen insula (text-figure 1) and is located at 64°17'S, 56°45'W, some 25 km east of James Ross Island (text-figure 2). The island is 20.5 km long and 9.6 km across at its widest point. The maximum elevation is approx imately 200 m (Elliot et al. 1975), although most of it is much less.
Even though the island is not covered by permanent ice, vegetative cover is absent due to the frigid climate prevailing in the southern high latitudes.
Seymour Island is separated into two unequal physiographic areas by a northwest-southeast trending valley, Cross Valley (text-figure 3). The terrain southeast of Cross Valley is hummocky, relatively low-lying and has been highly dissected by running water.
The smaller, northeastern portion of the island is dominated by a flat topped undissected meseta, 180-200 m in elevation (Andersson, 1906;
Elliot et al., 1975). To the northeast of the meseta is a small highly dissected area physiographically similar to the southwest portion of the island.
Steep sea-cliffs border the island except where meltwater streams debouch into the sea (Andersson, 1906; Zinsmeister, 1976b). Beach and intertidal morphology at any particular locality is controlled by sea currents and the movement of sea ice (Zinsmeister, 1976b).
3 4
ftlY M O U R ISLAND
ANiTARCTICA] o r
ISO
Text-figure 1. Map of Antarctica showing the general location of Seymour Island. 5
"’Joinville Island
p Erebus and Terror Gulf
Cockbum Island James Ross Island Seymour Island
Snow Hill Island
i 50 km 56°W __ I__
Text-figure 2. Map of the northern Antarctic Peninsula and the James Ross Island Group showing the location of Seymour Island. (After Trautman, 1976.) 6
Cape Wiman SEYMOUR ISLAND
Badman Point Lopez de B a s e / Bentodano Bay Marambio
\T h e Meseta Penguin 7 Bay
Weddell Sea
Penquin Point
Text-figure 3. Hap of Seymour Island showing the location of geo graphic features. 7
History of Exploration
Sir James Ross Clark discovered the James Ross Island group (text- figure 2), which includes Seymour Island, while exploring the north western portion of the Weddell Sea in ZS43. He landed on neighboring
Cockburn Island on January 6 and claimed the entire island group for the
British Crown (Ross, 1847). Although originally named "Cape Seymour"
(after Rear Admiral Sir George Francis Seymour), the insular nature of
Seymour Island was established by subsequent exploration during the early 1890's (Donald, 1893).
There is no record of any landing being made on Seymour Island until
December 4, 1892, when Carl A. Larsen, Captain of the Norwegian whaling ship Jason, explored a portion of the island, collected geologic sam ples, and claimed the whole of it for Norway. Larsen returned to the island during the following whaling season to collect additional fossils. The Larsen collection of fossilized plants and Tertiary Period invertebrates is the earliest Antarctic fossil collection still in exis tence today (Bertrand, 1971).
The Swedish South Polar Expedition (1901-1903) recovered a greater var iety of fossils than did Larsen, including Tertiary Period plants, invertebrates, penguin and whale bones, and Cretaceous invertebrates and plants.
Seymour Island was later visited by a number of expeditions of the
Faulkland Island Dependency Survey during the 1940's and 1950*s. 8
W. N. Croft mapped and collected numerous fossils from the Cretaceous and Tertiary systems during the 1946 field season. He resampled the lower part of the Tertiary System to investigate the gigantic fossil penguins that were known from these beds and recovered well-preserved bones (Harpies, 1953). Standring remapped Seymour Island in 1953 and clearly established the unconformable relationship between the Creta ceous and Tertiary systems (Adie, 1958). He collected Archeocete verte brae in the Tertiary System similar to those previously recovered from
Seymour Island by the Swedish South Polar Expedition.
Argentina established a year-round research station (Base Marambio; text-figure 3) on Seymour Island during the austral summer of 1969.
Extensive field work began during the 1973-74 season by geologists of the Instituto Antarctico Argentine. Happing and sampling were concen trated in the southern two-thirds of the island. At the invitation of the Instituto Antarctico Argentino the geologists of the Institute of
Polar Studies at The Ohio State University, and Northern Illinois Uni versity participated in the 1974-75 field season (Elliot et al., 1975).
The objective of the United States group was a detailed study of the stratigraphy, sedimentary petrology, and paleontology of the north eastern one-third of the island. The Argentine geologists continued their studies of the previous field season, concentrating on the Creta ceous System in the southwestern portion of the island.
Samples were collected for Northern Illinois University (NIU) for micro- paleontological investigations. A preliminary palynological study of 9 these samples revealed abundant palynomorphs, including rich dinocyst floras (Hall, 1977).
Geologic Setting
Tectonic uplift of the northern Antarctic Peninsula, associated with the
Andean Orogeny, created a foreland basin in the James Ross Island area by at least the Middle Cretaceous Period. The Mesozoic Era sediments cropping out in this region consist of coarse conglomeratic beds of the
Turonian Stage or older. The coarse basal units pass upward into sand stones and shales, the uppermost of which may be as young as the Maas- trichtian Age (Elliot, 1982).
An angular unconformity between the Cretaceous and Tertiary systems on
Seymour Island suggests that a phase of the Andean Orogeny led to uplift and erosion following the cessation of deposition of the Cretaceous
System (Trautman, 1976). Subsequently, during the Lower Tertiary
Period, a depositional basin was established over the Seymour Island area and sedimentation commenced anew.
The sediments were carried into the foreland basin by southeastward flowing rivers which drained highlands to the northwest. Petrologic studies indicate the source terrain was an emerging Cordilleran-belt, the remnants of which crop out on the Antarctic Peninsula. Rapid sedi mentation kept up with subsidence and all deposits accumulated under strandline or deltaic conditions (Trautman, 1976). 10
Stratigraphy
Introduction. The sedimentary sequence on Seymour Island originally was divided into the "Older Seymour Island beds" of the Cretaceous System and the "Younger Seymour Island beds" of the Tertiary System (Andersson,
1906). Although Andersson (1906) referred these beds to the "Cretaceous
Series" and the Tertiary "Seymour Island Series," he did not formally name or describe the units.
Recent fieldwork has led to a refined stratigraphic subdivision (Elliot and Trautman, 1982; Rinaldi, 1977, 1982). The Upper Cretaceous Series
(Campanian Stage-?lowermost Paleocene Series) are designated the Mar- ambio Group (Rinaldi, 1977, 1982), and consist of the Lopez de Bertodano and Sobral formations.
Elliot and Trautman (1982) have proposed the Cross Valley and La Meseta formations to include the Lower Tertiary System on the island. Together these formations constitute the Seymour Island Group.
The thin gravel beds capping the meseta in the northern part of the island are no older than the ?late Tertiary-Quaternary periods. They have received little attention beyond the recognition of their existence by Trautman (1976).
The Marambio Group. The Marambio Group is composed of the Lopez de Ber todano and the Sobral formations. The Lopez de Bertodano Formation is the basal unit of the Marambio Group and occupies the majority of the southern two-thirds of the island. The formation is composed of 11 approximately 1100 m of loosely consolidated tan to medium gray inter calated siltstone and concretionary sandstone beds. Samples from this formation were not studied in this investigation.
The type section of the overlying Sobral Formation crops out in a narrow strip along the southeastern coast, between Penguin Point and Cross
Valley. Limited exposures of lithologically similar deposits in the north, around Cape Wiman, are part of the Sobral Formation (Zinsmeister, in press); although Trautman (1976) and Elliot and Trautman (1982) ear lier equated them to the Tertiary Cross Valley Formation.
The Sobral Formation consists of at least 210 m of medium to coarse grained glauconitic brown sandstones. Glauconitic concretionary hori zons are common in the lower portion of the formation and are overlain by some 50 m of well-cemented, resistant sandstone beds. Localized con centrations of molluscs and carbonized plant debris, including logs, occur within the upper 100 m of the formation. The absence of charac teristic Cretaceous Period faunal elements was the reason that
Zinsmeister (in press) assigned the formation to the lowermost Tertiary
System rather than Upper Cretaceous (Maastrichtian?) System (Rinaldi,
1977, 1982; Del Valle et al., 1977).
The Seymour Island Group. Two formations, the Cross Valley and
La Meseta formations, make up the Seymour Island Group. The Cross
Valley Formation was proposed for fault block exposures of essentially nonmarine beds exposed in Cross Valley and at Cape Wiman (Trautman,
1976). 12
The type section is 106 m thick (text-figure 4); whereas 230 m are present in the northernmost part of the island (Trautman, 1976). The overall formation thickness may exceed 230 m because the outcrops in both areas seem to be in fault contact with the adjacent beds (Zins meister, in press). Earlier, Rinaldi et al. (1978) reported that the contact between the Cretaceous-Tertiary Systems in Cross Valley was dis- conformable.
The type section consists of poorly sorted, pebbly coarse sands and sandstones which pass upward into carbonaceous silts and silty-sandstone beds (Trautman, 1976). Large carbonized logs occur in the terrestrial sandstone beds which compose the lower 80 m of the section. Leaf impressions and carbonized plant debris are present in the overlying
20 m of tuffaceous silts and silty sandstones. The uppermost beds are thin, resistant sandstones containing poorly preserved marine molluscs
(Zinsmeister, in press).
Trautman (1976) proposed the Marambio Formation to encompass the Lower
Tertiary System marine deposits on Seymour Island. The name was not adopted because it was proposed in a thesis, rather than a legitimate publication; and because Rinaldi (1977) legitimately established the
Marambio Group for a different group of rocks. Since the name was pre occupied, Elliot and Trautman (1982) proposed the La Meseta Formation for the Lower Tertiary System.
The total outcrop thickness attributed to the La Meseta Formation varies from 370 m to as much as 480 m (Elliot et al., 1975; Trautman, 1976; La Mo iota Formation (A—A1} Unit
rjTtiMaramblo
Pf.v.w:
m m Bodmon m m Point w w Cross Voltoy eymour Formation /// sia m n o - n m m
I S i i l Uppor Tortlow to Oortomorr h H loo* M dopooin 00 too of ONI I Lo M u M POnoollw l« * 3 Pokoto Cnn MMoy POnooHM E23 | ftrtfory Ctotocoooo oodWtwoodotod 0 km 5 1 I « * ' I I. oKtp
Text-figure A. Stratigraphic columns of the La Meseta and Cross Valley Formations and a geologic location map. (After Trautman, 1976, and Welton and Zinsmeister, 1980.) 14
Zinsmeister, 1977; Zinsmeister and Camacho, 1982). The thickness reported by the 1974-1975 American-Argentine expedition was approxi mately 380 m (Elliot et al., 1975); this figure will be used in the present study. The La Meseta Formation has been informally divided into lithologic Units I, II, and III (text-figure 4).
Unit I, the lowermost unit, consists of at least 160 m of poorly conso lidated, dark gray to brown, thinly laminated very fine-grained sand and silty sands (Trautman, 1976; Zinsmeister, in press). Although fossili- ferous concretions occasionally occur, the plant debris characteristic of the Cross Valley Formation and the shell-banks that occur upsection in the La Meseta Formation are absent in Unit I. Unit I deposits crop out along the northwestern coast north of Cross Valley and at the north eastern base of the meseta near Cape Wiman.
The base of the overlying Unit II is marked by the lowermost pebbly sandstone shell bank in the La Meseta Formation. The discontinuous shell banks are cemented by calcium carbonate and contain mollusc shells and shark teeth. Shell banks up to 1.5 m thick and one kilometer in length have been observed (Trautman, 1976; Welton and Zinsmeister,
1980). Intercalated with the shell banks are much thicker deposits of unconsolidated, alternating, thinly laminated, very fine sands and dark silty clays. These laminated beds grade laterally and vertically into bioturbated mottled brownish-gray silty sand beds (Trautman, 1976).
Burrowed tree trunks occur in the laminated sand-clay beds. 15
The uppermost unit, Unit III, consists of unconsolidated, thick bedded and well sorted fine to medium-grained sands occasionally containing thin gummy clay interbeds (Trautman, 1976). Sheetlike pebble deposits and thin cemented medium-grained sandstone shell beds are intercalated with the thick homogeneous sands. Vertebrate fossils, including fossil penguin bones, occur locally in the upper part of Unit III.
Paleoenvironmental Setting
Trautman (1976) postulated a tide-dominated deltaic-complex as a deposi- tional model (text-figure 5) for the Tertiary System.
The Cross Valley Formation was considered to represent nonmarine high energy distributary channel and low energy interdistributary marsh or swamp deposits.
The informal lithologic units established for the La Meseta Formation by
Elliot and Trautman (1977) also represented different depositional envi ronments. The unfossiliferous finely laminated silt and silty-sand beds of Unit I indicate deposition in a low energy environment landward of the region of tidal influence (Trautman, 1976).
The combination of alternating fine sand and silty clay beds, sedimen tary and biogenic structures, and macrofossil accumulations indicated to
Trautman (1976) that Unit II consisted of tidally bedded delta front platform deposits. TIDE-DOMINATED DELTA COMPLEX
WESTERN SOURCE AREA OF HIGH RELIEF
.(FLUVIAL SYSTEM|
Distributary channels DELTA-TOP (NON-TIDAL DELTA-PLAIN) Interdistributary area M Cross Valley Fm. (marshes or swamps) TRANSITION (DELTA-PLAIN)
Tidal-channels La Meseta Fin. Unit 1 (marine mollusks, sharks teeth, etc.) DELTA-FRONT Tidal-flat (TIDAL-PLAIN) Tidal sand bars La Meseta Fm. Unit II Unit III
Delta-front gullies Local strandlines (pebble and bone lags) Low-energy embayments 'OPEN MARINE* (restricted fauna) types)
Text-figure 5. Generalized depositional model for the major lithologic units on Seymour Island. (After Trautman, 1976.) 17
Unit III, on the other hand, was envisioned to have been deposited in a shallow low energy marine environment.
The overall sequence of paleoenvironments according to Trautman (1976) indicates a local marine transgression. The terrestrial to estuarine deposits of the Cross Valley Formation are stratigraphically lower than the delta plain (Unit I), delta-front platform (Unit II), and shallow marine (Unit III) deposits of the La Meseta Formation. Some transi tional paleoenvironments are probably not represented because the con tact between the two formations is not continuous. PALEONTOLOGIC BACKGROUND
Previous Paleontologic Investigations on Seymour Island
The Early Tertiary Period fossils of Seymour Island have attracted the interest of geologists since the early 1890's. Although most of the fossils collected by the 1893 Larsen whaling expedition were considered to be "mostly Jurassic forms" (Donald, 1893), the molluscs were subse quently determined to belong to the Early Tertiary Period (Shaman and
Newton, 1894, 1898; text-figure 6).
The first extensive paleontological investigations were conducted on the large collection of fossils recovered by the 1901-1903 Swedish South
Polar Expedition (Wiman, 1905; Buckman, 1908; Dusen, 1908; Smith-
Woodward, 1908; Wilckens, 1911). Dusen (1908) concluded the age of the fossil leaf assemblage in the collection belonged to the late
Oligocene-early Miocene epochs. Wilckens' (1911) study of the molluscs from the Larsen and the Swedish expeditions led him to assign them to the Oligocene-Miocene Epoch. Smith-Woodward (1908) had only a few fish vertebral centra to study, but concluded they were from the early part of the Tertiary Period. Penguin bones collected by a field party of the
Faulkland Island Dependencies Survey were studied by Marples (1953).
Palynological study of a rock sample collected by the Swedish Expedition shed little light on the age of the Seymour Island deposits. Cranwell
(1959) noted the presence of reworked Cretaceous Period miospores and stated "For the younger component an Upper Tertiary limit cannot as yet
18 SYSTEM CUaDUOH DUSEN. HLCXENS. CRRNHELL SIMPSON. ELLIOT e t TRHUTMflN ZINSMEISTER ELLIOT I I 1908 1911 ( PflL YN0MORPHS) 1971 a i.1 9 7 5 1976 (MOLLUSCS. PflLYMO- TRAUTMAN NEKTON. (PLAIT (VERT (N0U1ECS. MOLLUSCS NORPHS) 1982 NE6R- EBRATE PREVIOUS HL1W- (PA.no- MOLLUSCS. F0SS1LS) 1 9 5 9 1 9 6 9 a 1 9 6 9 b[MOLLUSCS] FOSSILS) REPORTS) HDRPHS) MORPHS) PHLYNO- PERIODEPOCH 1 9 7 6 a )
MIDDLE SEYMOUR IS. BEDS 4 A . SEYMOUR Carly ISUMB SERIES
MIDDLE
Early e a r ly
Ttxt-flgure 6. Comparison of the strati graphic unit nones and ages assigned to the Lower Tertiary deposits on Seymour Island. The fossil groupls) upon which the age determinations were made are shown beneath each reference. 20 be hazarded: it contains types represented in early Tertiary deposits elsewhere in the southern hemisphere and seems to lack others, such as grasses, sedges, and composites, which are usually present by the Mio cene. " This noncommital statement was subsequently interpreted to indi cate an Early Tertiary Epoch age (Hall, .1977) and, more precisely, the
Paleocene Epoch (Elliot et al., 1975; Zinsmeister, 1976a, 1977, 1979, in press). Both interpretations are proven erroneous by Cranwell's own words. On page 3, Cranwell (1959) reports that Harrington had informed her that the Cretaceous System was separated from probable early Miocene
Series deposits by an angular unconformity. She then states "This clears up the longstanding confusion and makes it clear that no early
Tertiary deposits have been discovered."
Cranwell (1969a) subsequently suggested an age equivalent to the early
Tertiary Period (mainly Eocene Epoch) as well as to the Maastrichtian
Age to Paleocene Epoch (Cranwell, 1969b) "for the younger Seymour Island material." The latter age determination also was erroneously reported to be simply the Paleocene Epoch (Zinsmeister, 1976, 1979; Zinsmeister and Camacho, 1982).
The deposits also were assigned to the middle Eocene to early Oligocene
Epoch on the basis of an assemblage of large fossil penguins (Simpson,
1971). Simpson recognized that the penguin fossils were derived from a very limited part of the section and he accepted Cranwell's (1969b) determination that some of the deposits belonged to the Paleocene
Series. 21
Elliot et al. (1975) made the first systematic, stratigraphically
oriented fossil collections from Seymour Island. An age as young as the
Early Tertiary Period (in part Eocene Epoch) was considered probable for
the deposits.
Trautman (1976) considered the Cross Valley Formation and the Marambio
Formation (i.e., La Meseta Formation) to belong to the Paleocene and
Eocene series, respectively.
Investigation of the mollusc assemblage in the Elliot collection indi
cated to Zinsmeister (1976a) they were from the late Eocene-early
Oligocene Series. Palynomorphs indicated Paleocene Series, as well as
late Eocene-early Oligocene Series, deposits were present on Seymour
Island (Hall, 1977). Zinsmeister (1977) agreed with Hall's findings.
The confusion and the divergence of opinion regarding age determinations
is due to the nature of the sample material studied. All studies con
ducted prior to 1975 were based upon grab samples, often collected from
scree slopes, whose precise stratigraphic and geographic location were
unknown. It is hoped the collection of Elliot et al. (1975) will rec
tify the problem of sample quality.
In addition, macrofossils are not widely distributed throughout the Ter
tiary System of Seymour Island. Shell banks and localized concentra
tions are more typical of their distribution. Hopefully, the numerous
and widely distributed palynomorphs will provide a more complete chro-
nostratigraphic framework for the post-Cretaceous bedB. 22
Finally, the grab samples studied by earlier workers represented a variety of lithologies from different areas of the island. Conse quently, all of the geologic ages reported in the literature could well be represented by deposits somewhere on Seymour Island.
Paleogene Period Palynological Studies Pertinent to Seymour Island
The most relevant papers to the study of the Lower Tertiary System microplankton on Seymour Island are reports of other southern hemisphere investigations. The many papers of Cookson or Cookson and Eisenack (see references) reported on some of the first southern hemisphere dinocyst studies and were quite useful. Wilson's (1967a) paper on the dinocyst flora from the McMurdo Sound area was particularly important. Deep Sea
Drilling Project reports (Haskell and Wilson, 1975; Kemp, 1975) from the southern oceans provided important data concerning the paleogeographic and stratigraphic distribution of taxa. Lower Tertiary Period studies from southern South America are few in number but proved to be quite useful (Archangelsky, 1969a,b; Cookson and Cranwell, 1967; Menendez,
1965; Pothe de Baldis, 1966).
Lower Tertiary Period phytoplankton studies from Europe were useful, particularly those by Davey, Downie, Sarjeant and Williams (1966), Eaton
(1971, 1976), Benedek (1972), Bujak (1980), and Bujak, Downie, Eaton and
Williams (1980).
In addition to the aforementioned biostratigraphic and taxonomic papers, the indices to fossil dinocysts of Lentin and Williams (1977b, 1981) and 23
the analyses of organic walled dinoflagellates by Stover and Evitt
(1978) were indispensable. Although available to me only during the
final stages of this study, the catalog to organic-walled fossils pre
pared by Wilson and Clowes (1980) also is to be recommended.
Maceral Analysis
The routine study of palynomorphs provide a basis for age and gross paleoenvironmental determinations. However, the total assemblage of particulate organic debris extractable from sedimentary deposits
(macerals) can provide additional information to supplement that derived
from classical palynomorphs.
Sedimentary deposits are a mixture of inorganic and organic constitu
ents. Mineral grains, rock fragments, cements, and mineral skeletal parts (i.e., shell, bone, teeth, etc.) comprise the former. The organic
constituent is composed of organic molecules in monomeric and polymeric
form derived from organisms (Tissot and Welte, 1978).
The lithologic character of a particular deposit is determined by the
relative percentages of the inorganic and organic constituents (text-
figure 7). At one end of the compositional continuum are organic rich
rocks, such as peats and coals. At the other end, are organic poor
lithologies, such as quartz sandstone. Gradational lithologies, charac
terized by varying percentages of organic and inorganic components exist
between the end members. 2k
100% ORGANIC MATTER
Text-figure 7. The compositional continuum of sedimentary rocks based upon relative amounts of organic and inorganic constituents. Organic rich lithologies are to the left; organic poor lithologies to the right.
BIT UMEN KEROGEN
NONPARTICULATE KEROGEN
PARTIC U L AT E KEROGEN
Text-figure 8. The classification of organic matter in sedimentary deposits. 25
Sedimentary organic matter can be classified as either bitumen or ker- ogen (text-figure 8). Bitumen is the organic fraction extractable from the rock with organic solvents, whereas kerogen is the fraction insol uble in either aqueous alkaline or common organic solvents (Tissot and
Welte, 1978). Palynological studies are primarily concerned with the kerogen fraction.
The majority of kerogen occurs as finely dispersed, amorphous or partic ulate debris. Discrete organic clasts (such as spores, pollen, dino cysts, and plant tissues) constitute a relatively minor part of the total kerogen content in most sedimentary deposits; usually no more than a few percent (Tissot and Welte, 1978). It is this minor component of kerogen which is of primary interest to palynologists. These clasts generally must be larger than 1|J to be identified by standard techniques of light microscopy. Such clasts are referred to herein as "macerals".
Macerals. The Glossary of Geology (Gary et al., 1972) defines maceral as "organic units that comprise the coal mass; all petrologic units seen
in microscope thin sections of coal. Macerals are to coal as minerals are to rocks."
On the other hand, Hart (pers. comm., 1977) reasons that coal is the organic-rich, inorganic-poor end member on the compositional continuum, as noted above (text-figure 7). This suggests the less abundant organic clasts observed in organic poor shales and sandstones are basically the same as those reported from organic rich coals. Therefore, the defini tion of maceral is broadened to include all acid-resistant particulate organic debris dispersed in sedimentary deposits. 26
Maceral analysis is the characterization of the acid-resistant, particu late organic debris. Such analyses determine the maceral spectrum of each sample. This includes the (1) types of macerals present,
(2) relative percentages of maceral types, (3) degree of degradation, and (4) presence and degree of thermal alteration (Wrenn and Beckman,
1981).
Maceral slides were microscopically analyzed through transmitted light.
The macerals were counted and classified according to type, color, and preservation. Counts of 50 macerals per sample were made and tabulated on a counting sheet, as illustrated in text-figure 9.
Four major categories of macerals are recognized: (l) phytoclast (plant cuticles, tracheids, miospores, etc.), (2) protistoclast (clear unstruc tured membranes, microforaminifera, acritarchs, dinocysts),
(3) scleratoclasts (fungal hyphae and spores), and (4) amorphous infested indeterminate (All). This is organic matter so completely altered or degraded as to be unassignable to any other maceral category.
All macerals may result from: (1) intense biodegradation of phytoclasts or protistoclasts, (2) agglutination of dissolved humic and comminuted substances, and (3) fecal pellet degradation (Hart, in preparation).
Total Organic Carbon and Maceral Analysis. The combined application of total organic carbon (TOC) and maceral analyses is a powerful tool for palynologists. Maceral analysis provides a qualitative assessment of the particulate organic debris present in a sedimentary deposit. TOC analysis is a quantitative measure of the organic carbon concentration MIOSPORES SCIIRATOCLAST PROT1STOCIAST PHVTOCLAST Text-figure 9. A Maceral counting sheet. counting Maceral A 9. Text-figure aiiiitii i i i i i l ■ ■■■■■■■■■■•■•■a ill W IliiillE H B i t i l l B B H H R H M | B R R « R R R I B R B l R B t B B I E R R I « B POOR ii:;iiii;:ii..ic i i i i i i i i i i n i i iic .3 INFESTED E ■■■■■■■■ ■RalRIRR ssttic:: ■■Dktiii AMORPHOUS
76 « a i i i i a i i S R E I I « i i i R i | i i a B i D l i l R B I S l i a i D I I R R I I R I R AMORPHOUS INFESTED LD # SLIDE AT 1*71 HART, "Nj N> 28
in sedimentary deposits. It measures the noncatabolized organic matter,
exclusive of carbonate material.
The combined maceral and TOC analytical approach provides a qualitative
and quantitative assessment of the entire organic debris spectrum.
Detailed maceral analysis promises to provide more refined paleoenviron- mental interpretations as shown in recent studies of the Mississippi
River deltaic complex (Hart, pers. comm.), and in differentiating modern freshwater and saltwater marsh deposits from splay deposits (Beckman, in preparation).
This technique was applied in the present study to elucidate strati- graphic trends and paleoenvironmental data in the Seymour Island Lower
Tertiary sequence.
Maceral and TOC Analyses Related to Source Rock Analysis
Source rock quality is defined in terms of the abundance, type, and
thermal maturity of the organic matter present. Whether a potential
source rock can generate oil, gas, or a combination thereof may be determined only after these characteristics are known.
Total organic carbon (TOC) analysis can determine the abundance of organic matter in a rock sample. Minimum TOC percentages for source
rocks of different lithologies have been established by empirical studies (Ronov, 1958; Schrayer and Zarrella, 1963; Hunt, 1967), and gen erally, TOC content increases as sediment grain size decreases (Ronov, 29
1958; Gehman, 1962). The minimum level for shales is 0.5% TOC (Tissot and Welte, 1978) whereas hydrocarbon generation may occur from fine grained carbonate source rocks whose TOC content is as low as 0.3%
(Hunt, 1967). Minimum values of 1.0-1.5% TOC are recommended by some geochemists because the recycled organic matter, which is present in most rocks, is carbonized and cannot generate hydrocarbons (Hunt, 1979).
This is particularly true of clastic deposits.
The types of organic matter in a sample can be differentiated by com paring the atomic ratios of hydrogen to carbon (H/C) and oxygen to carbon (0/C). Three major types of organic matter ("kerogen" in geochemical terminology; Tissot and Welte, 1978) are differentiable
(text-figure 10).
Type-I kerogen consists primarily of amorphous and algal material (dino cysts, Botryococcus, Tasmanites, etc.). Type-II kerogen consists of a mixture of types I and III kerogen. Type-XII kerogen consists of humic, opaque and coaly material; some amorphous material may be present
(Tissot and Welte, 1978).
Thermal maturity and the H/C and 0/C ratios determine when and what type of hydrocarbons are produced. All three kerogen types may generate liquid and/or gaseous hydrocarbons, although the point at which genera tion begins varies between types (text-figure 11).
The type and thermal maturity of organic matter can be determined and generally related to the atomic ratios of H/C and O/C by maceral 30
Kerogen Pr i nc i paI Hydrocarbons Type Maceral Generated Types
Prot istocI asts Oi I I All
Prot i stocI asts All Oil and Gas II Phytoe I asts (Uet Gas) Sc I eratoelasts
Phytoe Iasts Gas III Sc I eratoe Iasts (Dry Gas)
Text-figure 10. A comparison of the Kerogen ana maceral types depicting the types of hydrocarbons each uould generate under ideal conditions. » ATOMIC O/C
Text-figure 11. Van Krevelen type diagram depicting the point at which hydrocarbons begin to be generated by the various kerogen types. 32 analysis. Protistoclasts and All macerals are the same as the chemi cally determined type-X kerogen whereas phytoclasts, scleratoclasts, and inertinite equate to type-ill kerogen. The generalized relationships between macerals, kerogen types, and the hydrocarbons generated as shown in text-figure 10.
The thermal maturity of the maceral spectrum can be determined optically because miospore coloration darkens as thermal maturity increases. A miospore color index (MCI) and its relationship to thermal maturity, paleotemperature, depth of burial, and sequence of hydrocarbon genera tion is shown in text-figure 12.
MCI values were recorded in this study for specimens of Nothofagadites spp., whenever possible, in order to facilitate the comparison of thermal maturity between samples. This restricted the effect on mio spore color due to the varying rates of thermal maturity for different types of spore and pollen grains as reported by Gutjar (1966). SUBSIDENCE VITRINITE MAXIMUM MIOSPORE THERMAL HYDROCARBON DEPTH REFLECT ENCE PALEOTEMP- COLOR MATURATION M %Re ERATURE °C INDEX GENERATION I IMMATURE 0.5 6 0 •
INITIAL 0.7 80 -
MATURITY 0.9 100-
1.1 120 - ■
1.5 MO- M AT U R E Ol L 2.0 160- WET 2.5 180* G AS
POST 1 0 MATURITY 4.5
Text-figure 12. Diagram showing the relationships between depth of burial, paleotemperature, vitrinite reflectance level, miospore color, thermal maturation, and hydrocarbon generation. RESPITS OF THE GENERAL LITHOLOGIC EXAMINATION
Sediment Grain Size Distribution in Section 3 . Most samples in Sec tion 3 were composed of very fine and fine sands, either lithified or unlithified (text-figure 13). Two samples were muds, two were silt- stones, one was a medium sand and one was a pebblestone. Three samples overlapped adjacent grain size groups.
Two major shifts in sediment grain size are evident from the base to the top of the section (text-figure 13). The very coarse pebblestone sample
(sample 8459) and the medium sandstone (sample 8454) represent two per iods of relatively coarse grained sedimentation. Conversely, samples
8477 and 8479 represent periods of very fine grained sedimentation.
Sediment Grain Size Distribution in Section 12-13. Sediment grain size ranged from mud to very coarse sand with granules. Coarse grained sedi ments were confined to the lower two-thirds of the section (text- figure 14). The uppermost samples were composed of mud to fine grained sand sediments.
Sediment Grain Size Distribution in Sections 15 and 16. Sediment grain size ranged from fine to coarse sand in the combined Sections 15 and 16.
Fine to medium sized sand predominated and the overall grain size dis tribution increased from the base of the section to the top (text- figure 15).
Sediment Grain Size Distribution in Sections 17, 18, and 19. Sample sediment grain size ranged from very fine sand to coarse sand size; most
34 35
SEDIMENT GRAIN SIZE
s n n r L t NUMBER VERY FINE FINE MEDIUM PEBBLE MUD S1LTST0NE SflND SRNDST ONE SANDSTONE STONE
_ 4*4***4t»4 8456 1440444444
8455
8479 V.V.V.W.’. ■
8454 - 444«4«(*4(
| ■ 4 4 4 8478 •X*»!
8477 -
44«4*4>*4I 8453 - M * 4 4 4 4 4 4 4
4444444441 8451 - 1(444 4 4 4 4 4
8452
8450 »!*»»!*»]
4444 4 44444 - • V 4 % \ \ W * V 8448 . v . w v ^ w v
8449 1(4*44(4*4
8447 _ ; * > w v ; v ; v
8476
r;v.v.v*v«v - 8475 .
P*VM * « « « • 4 |(44«4440«4 - |4 444444444 8474 1 4 4 • • 4,4 4 4 * 1
14 4 4 4 14 1*4 /.•.V.'.V.'.S' - 144444*44*1 6446 .•.V.V.»4*4*4V-
'(■(■(■4*4’ 4T4't’ 4’4
8444 - W.V.V.V.'.
I44***4**44 8445 - T*xt-flgur* 13. S*dim*nt grain Biz* distribution in Section 3. 36
SEDIMENT GRAIN SIZE SAMPLE NUMBER VERY FINE FINE MEDIUM PEBBl E MUD SILTSTONE SflND SANDSTONE SANDSTONE STONE
8473 WOOD
8472 [ 1 t 1 i V l t 1 t
* • • • • • « »«•••< 8443 ■•V.--
i r m r r r n ; 8469 -
8470 -
8471 - WOOD
8467 - L2JU
8468 -
8466 -
8465 -
8464 -
8463 -
8462 - » « 4 4 4 <
8461 -
8459 -
i m i n ' i , r < 8460 - 4 *4 % V r nmmn
8458 -
8457 -
Text-figure 13 (CONT'D). Sediment groin size distribution in Section 3. SEDIMENT GRAIN SIZE SILTSTONE MEDIUM TO TO FINE TO MEDIUM TO VERY COARSE SAMPLE VERY FINE MEDIUM VERY COARSE SAND KITH NUMBER MUD SANDSTONE SBNO SAND GRANULES 8494
8493
8492
8490
8491 BONE FRAGMENT
8489
8488
8487
8485
> ft 4 4 ft ft • • 848B 4 ft • ft 4 4 «
ft ft 4 ft ft < ft • • 8483 Tft’ft4*4*_*ft*ft ft ft 4
• ftft«ft*«ft*i 8484 **44*4 •» f
ft ft 4 ft ft ft ft 4 ft i >•*•••*v► ft * ft « * 4 v ft .v ft *ft ft 8482 ft 4 ♦ ♦ 4 .4 . j_ q
8481 "I 4441144IJ \V*V.\V.V, 8480 E
Text-figure 14* Sediment grain size distribution in Section IE-13. 38
SEDIMENT GRAIN SIZE
FINE MEDIUM TO TO SAMPLE MEDIUM MEDIUM COARSE SECTION NUMBER SAND SAND SAND
8499
1 6
«««•***** 144*44«»*« 8498 44**444»*««444*V4«4* - - * * «-» * - * «
4 4 4 4 ft 4 4 4 4 8497 «444*Y444*
15 8496
44444444*4 8495 * 4 4 4 4 4 4 4 4 ■4^^ f 4 ~44 f 4 4
Text-figure 15 Sediment grain size distribution in Sections 15 and 16. 39 samples were either very fine or fine sand or sandstone (text- figure 16). In general, sediment grain size increased from the base to the top of the composite section, with three recognizable cycles of fine to coarse sediments. 40
Z o SEDIMENT GRAIN SIZE SAMPLE S'TTT FINE "MEDIUM o NUMBER TO TO TO UJ VERY FINE FINE MEDIUM MEDIUM MEDIUM COARSE LD SAND SAND SAND SAND SAND SAND i l l i U i U I 8512 • * 4 < 4 4 4 4 4 4 »** «*■*»*4*4*4*4V
8511
8510
19 8509
’4 % V « W . V i • * * * * 4 4 < 8508 I * 4 M 4 4 4 4
7 7 7 7 7 ^ 7 7 8507 . t 4 « 4 « 4 4 « « I 4 4 4 4 « 4 4 t 4 ♦
8508
8505 4 4 4-44 44 * 4
18 8504
8503 I 4 4 * 4 4 * I W J W . W . ' l 8502 44444-4444
17 8501
8500 Text-figure 16. Sediment grain size distribution in Sections 17. IB and 19. RESULTS OF THE PALYNOLOGICAL INVESTIGATION
General Statement
The seventy samples studied in this investigation were collected from
seven outcrop sections located in the northeastern one-third of Seymour
Island (See Appendix B).
Samples of Sections 12-13, 15, and 16 were collected from the Cross
Valley Formation, whereas those from Sections 3 and 17-19 came from the
La Meseta Formation.
The sample processing procedures for palynological, maceral, and TOC
analyses are outlined in Appendix C. All slides are housed in the
Botanical Micropaleontology Laboratory, Department of Geology, Louisiana
State University, Baton Rouge, Louisiana.
Fifty microplankton were identified and counted on each of six slides per sample. This yielded a total count of 300 individuals. However, microplankton assemblages in some sample preparations were so sparse,
the total count fell short of 300.
Spores and pollen were counted and identified to the infra-turma level
contemporaneously with microplankton data collection. No specific number of spores and pollen were counted; rather tabulation continued only until the microplankton count for each sample was completed.
Detailed work was confined to the microplankton groups. Sixty-seven
samples yielded microplankton and of these concentrations were good to
41 42 excellent in forty-nine samples. Microplankton were poorly represented in the remaining 18 samples. Spores and pollen were present in all but one sample.
The microplankton were more abundant than spores and pollen in all sam ples of Sections 16, 17 and 18, and in most samples of Sections 3, 15 and 19. Pollen and spores were much more abundant than microplankton in all samples of Section 12-13.
Reworked dinocyst and/or pollen floras were common in most samples of
Sections 3, 17, 18 and 19. Reworked dinocysts accounted for from 13 to
31 percent of the total dinocyst floras in the la Meseta Formation.
Sections 15 and 16 do not contain any reworked dinocysts. Determination of reworking in Section 12-13 is precluded by the structural complexity of the sampling area. (See the discussion of Section 12-13 below, under
"Age Determinations".)
Forty-four dinocyst genera containing 75 species and five subspecies were recovered, of which two genera and 10 species are new. These new taxa are not officially established herein, although they are described in detail. Six genera and five species of acritarchs, two genera of
Pterospermatales, and two genera and three species belonging to the
Chlorococcales were recovered.
Table 1 shows the microplankton species recovered from each section.
Tables 2, 3, 4 and 5 record the stratigraphic distribution and frequency of each microplankton species, spores, pollen, macerals, and TOC in 43
Table 1. The microplankton species present in the Seymour Island sec tions .
Section Species 3 12-13 15 16 17 18 19
Achomosphaera sp. X X X Aiora fenestrata sensu Wilson, 1967 X Alisocysta circumtabulata X X X Alterbia sp. A. X Aptea securigera X Aptea sp. X Areosphaeridium diktyoplokus X X X X Baltisphaeridium ligospinosum X X X X Botryococcus sp. X Ceratiopsis boloniensis X Ceratiopsis dartmooria X X Ceratiopsis speciosa X X Ceratiopsis striata X Ceratiopsis sp. X Cerebrocysta bartonensis X Chytroeisphaeridia explanata Cleistosphaeridium anchoriferum X Comasphaeridium cometes X X X Cometodinium cf. whitei X X X Cribroperidinium edwardsii Cribroperidinium muderongense X Cribroperidinium sp. X X Cyclonephelium distinctum X X Cyclopsiella elliptica X Cyclopsiella trematophora X X Cymatiosphaera sp. X X Deflandrea antarctica Type I X X X Deflandrea antarctica Type II X X X Deflandrea cygniformis X Deflandrea oebisfeldensis sensu X Cookson & Cranwell, 1967 Deflandrea cf. phosphoritica X Deflandrea sp. A. X Deflandrea sp. X X X Diconodinium cristatum X Diconodinium multispinum X X Dinogymnium cf. curvatum X Eyrea nebulosa X X X X X Forma-A X Forma-B X X Hystrichosphaeridium cf. astartes X Hystrichosphaeridium parvum X XXX
Hystrichosphaeridium salpingophorum X X XX XX XXXX XX XXX X XXX X XXX XX 44
Table 1 (continued)
Section ______Species______3 12-13 15 16 17 18 19
Hystrichosphaeridium tubiferum X X XX subsp. brevispinium Hystrichosphaeridium sp. A. X XX Hystrichosphaeridium sp. X Impagidinium dispertitum X Impagidinium maculatum XX X Impagidinium victorianum X Impagidinium sp. X Impletosphaeridium sp. A. X X X XXX X Impletosphaeridium sp. B. X XX Impletosphaeridium sp. C. XXX XXXX Isabelidinium druggii X Isabelidinium pellucidum X X Kallosphaeridium cf. capulatum XX X Leiofusa jurassica X X lejeunecysta fallax X Lejeunecysta hyalina X X Lejeunecysta sp. X X X Micrhystridium sp. A. X X Odontochitina cf. operculata X Oligosphaeridium complex X XX Oligosphaeridium pulcherrimum X Oligosphaeridium sp. X X Operculodinium bergmannii X X XX Ophiobolus lapidaris X XX XX Palaeocystodinium australinum X X Palaeocystodinium golzowense XXX X Palaeocystodinium granulatum X Palaeocystodinium sp. X X Palaeoperidinium pyrophorum X XXX X X Palambages Forma B. (of Manum and X Cookson, 1964) Palambages morulosa XX X X Palambages Type I X X X Paralecaniella indentata X X XX XX X Pareodinia sp. X Phelodinium sp. A X X XX X Pterospermella australiensis X Phthanoperidinium echinatum XX X X Selenopemphix nephroides X Senegalinium asymmetricum X X X Spinidinium densispinatum XXX X X Spinidinium essoi X X X X X Spinidinium lanternum X X Spinidinium macmurdoense X X X X Spinidinium sp. A. X X X X Spinidinium sp. X X XXX X 45
Table 1 (continued)
Section Species 3 12-13 15 16 17 18 19
Spiniferites cf. cornutus X Spiniferites ramosus XXX Spiniferites ramosus subsp. X X granomemb rana ceus Spiniferites ramosus subsp. granosus X Spiniferites ramosus subsp. X X multibrevis Spiniferites ramosus subsp. XX XX X reticulatus Spiniferites sp. X XX X Tanyosphaeridium xanthiopyxides X Thalassiphora pelagica X X Thalassiphora velata X Trigonopyxidia ginella X Turbiosphaera filosa X Veryhachiura sp. X X Vozzhennikovia apertura X X X Vozzhennikovia rotunda X X X XX Xylochoarion cf. hacknessense X 46
Sections 3, 12-13, 15 and 16, and 17 through 19, respectively. The local stratigraphic range for each microplankton species in Sections 3,
12-13, 15 and 16, and 17 through 19, are shown in Tables 6, 7, 8 and 9
(by stratigraphic tops) and Tables 10, 11, 12 and 13 (by stratigraphic bases), respectively.
Tables 6 through 13 show that some species have a locally restricted stratigraphic range; this suggests that the establishment of a micro plankton zonation is possible. However, the nascency of microplankton and stratigraphic studies on Seymour Island, the presence of many long- ranging taxa and the wide sampling interval of the samples studied indi cate any attempt at such a zonation is premature.
Rare specimens of diatoms, silicoflagellates and scolecodonts were observed in some samples. Fungal debris occurred in many samples, occa sionally in great abundance.
Nineteen samples were processed for nannofossil examination; all were barren (Robert W. Fierce, pers. comm.).
General Palynology of the Sections
Section 3 . Thirty-seven samples from Section 3 were studied, of which
25 were highly productive, 12 were poorly productive and three were essentially barren. Fifty-three dinocyst species and six acritarch spe cies were recorded (Table 2). Two genera and two species of the Chloro- coccales also were recovered. Thirty-two percent (17 species) of the dinocysts and 17 percent (1 species) of the acritarchs were reworked forms. 47
Dinocyst species diversity (text-figure 17) was slightly higher in the bottom half (X=11.5) of Section 3 than it was in the upper half
(X=9.1). Species diversity variability decreased slightly from the base to the top of the section. Species diversity decreased as grain size increased, but only markedly in medium sand sized sediments or larger (text-figure 18).
Goodman (1979), who studied species dominance and diversity in dinocyst communities of the Nanjemoy Formation of Maryland, U.S.A., defined domi nance as:
N 1 + N2 Dominance = — ---- t where Nj is the frequency of the most abundant species, is the fre quency of the second most abundant species, and is the total number specimens in the sample. Species diversity was shown to increase in an offshore direction, whereas species dominance decreased in the same direction (Goodman, 1979).
Species dominance in Section 3 ranged from 17% to 94% (X=59.3%) and was slightly more prevalent in the upper half (X=6l.2%) of Section 3 than in the lower half (X=57.5%). Overall, species dominance did not show any strong trends, either stratigraphically or in relation to sediment grain size. This is due, in part, to the relative uniformity of sedi ment grain size within the samples studied. Most samples were either very fine or fine sands and sandstones. The mud, siltstone, or pebble stone saoqiles were too rare to establish the presence of any trends. SAMPLE PERCENT SPECIES DOMINANCE SPECIES DIVERSITY NUMBER 25 SO 75 100 0 10 15 20 25 -J------1______» L_ 8456 - _L 8455 - 8479 - 8454 B478 8477 - 8453 - 8451 B452 8450 8448 - 8449 - 8447 -i 8476 - 8475 - 8474 - 8446 - 8444 8445 8473 - 8472 - 8443 - 8469 - 8470 8471 8467 - 8468 - 8466 8465 - 8464 8463 - 8462 - 8461 - 8459 - 8460 - 8458 - 8457 -
inure 17. Di nocyst species diversity and dominance in Section 3. <7> m <\i
(0
o . CM
CO 0£
Q Ifl. (A >- U O z *—I Q Lfl - O -J T ~T 1 I I F T 1 I I I I 1 I I I FT FT FT plotted against sediment grain size. mo: I I I I I I I I I I -I 111 Da cmCrtO(fi(»)N«o(nhco Lnin(M CO I CO < o CO 1 li. co (A co CO c o Text-figure Text-figure IB. Dlnocgst species diversity Ssctlon In 50 Chorate dinocysts species were recovered from all but three samples (text-figure 19). Chorate species abundances ranged from 12% to 100% (X=28.7%) and were more common in the lower half (X=33.2%) than in the upper half (X=24.2%) of Section 3. The distribution of chorate dino cyst species was not related to sediment grain size. Cavate dinocyst species occurred in all but two samples of Section 3 (text-figure 19). Cavate species abundance ranged from 8% to 67% (X=29.8%) and were almost three times as abundant in the upper half (X=43.7%) of Section 3 than in the lower half (X=15.9%). The abun dance of cavate dinocysts increased slightly as sediment grain size increased. Proximate dinocyst species were present in all but two samples of Sec tion 3. Proximate dinocyst abundances ranged from 33% to 72% (X=44.2%) and were slightly lower in the upper half (X=43.2%) of the section than in the lower half (X=44.2%). Proximate dinocyst species did not appear to be related to sediment grain size. Spores and pollen were generally well represented, although three sam ples were essentially barren. Saccate pollen were recovered from all samples except samples 8459 and 8461 (text-figure 20). Abundances of saccate pollen ranged from 3% to 54% (X=28.3%) and concentrations were essentially the same in both the upper (X=27.7%) and lower (X=28.7%) halves of Section 3. Sediment grain size was not generally related to the abundance of saccate pollen in the samples of Section 3. PERCENT SAMPLE NUMBER 0 25 50 75 100 i I I I | " T i I—r | 1 i i r | l l i i | 8456 , v*v.\v.v.v.v.v.v.v*v '///X **• '!• *•********#*♦****•* «.« '♦***• ********** »•» 8455 ?»• t’ T* *r« *.?•• »•*?• 'i • i************* ’ 4 4 * * 4 • 4 4 4 1 * f r-.v.v.v.v.v.v.w 8479 • I****t444«**i«4l V7/7lilSaB *44»**«44*4*t«4 8454 y y y y ■,* ,■ .»• 4*4*4*******»*#***44 y y y y v******************* 8478 r X X X 4 4* 4* 4 444 ** 44 ** •*•••« **V*V**.V*V*V4V4V*\V*V 8477 • **» . • *•**•**•*** *.* • • • * * * /// • ■ i* * t » 4 4 l»»«*4«444 4*44*4 .'.•.’.'.'.'.’.•.V.V.-.V.- ftt4ft*4*«***4«4 *4*l*»*(4***44** 8453 '///I 4*t44444*ll*4*44 **•*•4**4 »>* ««44«4t»» 4444lt**4t«4tt**f**44«t»f*»44****«*t(4|** 8451 4*l*4*«**«4(*(****4*t vzmtim *f*t4«»4»»4*«»* 4 ♦ • * • i^rrrmTT 8452 zzzsEEMmam 4*l**4*f**44**4*4* 444444t*4*4***444 4*4**4****444 44444 8450 *4*4***4****«44** V// 44 4444*4 *44* 4 4 44* 4 i * * * • 4 * * * * * * * * • ►•,»»*•>**■> *♦»♦*•••*•*** • *?. * >*•••***»***** 8448 ■ #**♦*****•*** 7ZZ/ZZZ • * 44*4*44 *•**«* . **444***»*44*«** *44**4*44*44444444 4444 9 **** *44*4 *4 ’ ,*44444444444444** 8449 ZZZZ/ZM * *4*4 •♦••••**♦♦ 44 *4***444**«4***44*»* ,.'4 ***#44*4* 1 4*4*4 ***4 * ,»• * • *4*4 * **•«*#♦****•* 8447 ■ <4 4 *44 4 44*4 4444* *4*44 * VJ77Z71 ****«4**»**«**4 t**t* I’N’It*'.'".*' •■.** 1 4 *4#444444* *444444441 ‘ l* • • 'Ii' *4******* *.* * * * 4*44*4 8478 •‘ .i ’ .' . • 'i**.* *r« * 44444*44441 4444444444 V//,* .'!.** 444*444444*444**4444 X X X X y JT- * »‘i.» !• #***4****4*4**4*44*4*| y X X X X / *• *• • *»«*4*44l 44 4,4 4.4 • 4 ' X X X X X . *4**4 4444444444 *4*444 x x x x x **•***•*♦**#***•*•*• 8475 X X X X X 44444444444444444444* *444** ********* 44 • 4*44**«4«**4***4* 8474 • *••»**«***♦** 44* V7/Z7fPil *_•. *. 4_ *. •^4^4m*.*.*.*»»X. / / / *:^***; : : • ; : .’ / / i v / I v A V / . v / z i / / / *V.V,V,V.V.*.**V*V. 8446 X X . ‘ 4444*44444444444 4444444V************ ,•*44*4*444* l44***4**4t .• •******«**4444*4***4 8444 , 4^*4444444 4 444*4***** z^siisa **4*******«44444**44 8445 BARREN LEGEND: CHORATE f H CAVATE F!?3 PROXIMATE Text-figure IS. Distribution of dlnocyst types, by percent, in Section 3. PERCENT SAMPLE NUMER 0 25 50 75 100 | 1 1 II | I I I I | I I 1 1 | I II 1 | ' // / / / / / / eee^eeeeseeese* 4 8473 / / / / !••:!«:» 44*4444444t*44« j 4 8472 V/////Ammms- 4 X X X X J *4***T*T*ee*4*e * 8443 ^ XX XX XX XX 4 8469 Xr /X , ••V;**;**'. *eeeee«<*ee^4ie*eee»444444444444444*44 4 X X X X '/?■ * eeeseeee****** 8470 X X X X • / X *44444444444**444 « 8471 XX XX X •♦«♦*«♦#•*«♦♦**«♦.W**V,*WW*.V*X-*XX., 4 8467 V////y 4 4 8468 '//////mm- 4 X X 41 *’ 8466 XX ^ 'J« ' • *444*44444444444444444 4 x X X X X we’e'e^e’e 4 8465 ' XX XX XX XX XJ 4*444*4*4144 Tee********* 4 X x it*************** 8464 XXXX X ♦ *4*44*41*1444414♦*•♦*«**«♦«**♦♦« 4 X X X X y 4 8463 rX XX XX XX XX ^t********* eeeeesee*** 4 X X X X X » 444441444144 8462 X X X X X *. ♦♦444*eeeee4e 4 X X XX X '••J*1: *44^44^444444 4 8461 XX XX X X XX XX > *eeee*e*«*e44 iii********** 4 8459 V/////////////.✓ V y / / J >i****Mli44444 8460 1 8458 ///////. 8 * * 8457 J LEGEND: E3 CHORATE EU CAVATE PROXIMATE Text-figure 10 CCont'd). Distribution o-f dlnocyst types, by percent, in Section 3. 53 PERCENT SAMPLE NUMBER 0 25 50 75 100 [ i' r i i ■|"T' i i-1 | n rr i "f i r ' i 1 6456 (///ArnmMWMiMimiMm 6455 yyyyy. 6479 vz/MmmiiiMrnimm 8454 6478 6477 vyyy/Tmmmmrn B453 8451 6452 '/yyymmmmss 8450 VAimmmvrnismm 8448 ////yMmmmsasim 8449 8447 6476 X/7'/yi&$@&6&8l88SMSfa$6$i 6475 yyyyyy/7mmmm 6474 6446 6444 \yy^&gmMm®ig$M& 6445 lymimmiiiammmm LEGENDt E J SACCATE E H OTHER EI51 SPORITES POLLEN Text-figure SO. Distribution of spores and pollen, by percent in Section 3. PERCENT SAMPLE NUMBER 0 25 50 75 100 I " n i"T | i r"i i | i i i i | i i ' n | 8473 8472 8443 8469 8470 8471 8467 \Z//sSMMiimml 8l 0i s * t t 8468 ////ismmmmmmm 8466 t'A/ymimmmmmiMt 8466 8464 8463 8462 {////AMMiitiMsitmiMlM 8461 8459 BARREN 8460 F7777//MmiimmMk 8456 rs/Z/MsmmemMmm 8457 LECEND: E 3 SACCATE e u 0THER S 3 SP0R1TES Tsxt-flflurs SO (CONT'D). Distrl button of sports and poflsn. bu psrcent. Jn Soctlon 3, 55 Spores were recovered from all samples, except 8454, 8445, and 8459. Spore abundances ranged from 1% to 23% (X-7.9%). Spores were approxi mately 50% more abundant in tbe upper half (X=9.4%) of Section 3 than in the lower half (X=6.3%). As with the saccate pollen grains, spore distribution was not generally related to sediment grain size. Microplankton were more abundant than spores and pollen in most samples. However, the spores and pollen were much more abundant than the micro plankton in samples 8447, 8451, 8462, 8475, and 8479. Section 12-13. Fifteen samples from Section 12-13 were studied (Table 3). Dinocysts were present in 66% of the samples in Sec tion 12-13; however, abundances were exceedingly low in all samples except the four uppermost samples. Fifteen species of dinocysts, two species of acritarchs, and two species belonging to the Chlorophyceae were recovered. Proximate species were the most abundant type of dino cysts in all samples except 8493 (text-figure 21) and ranged in abun dance from 12% to 50% (X=27%) in the upper four samples. Cavate spe cies were the dominant type only in sanqple 8493 whereas chorate species were dominant only in sample 8493. Chorate species were the least abun dant dinocyst type in Section 12-13. The abundances for this group ranged from 17% to 38% (X=25%) in the upper four samples. The dino cysts were most abundant in the finer grained sediments at tbe top of the section. Spores and pollen were well represented throughout Section 12-13, although concentrations were generally higher in the four uppermost SAMPLE PERCENT NUMBER 25 50 75 100 ] I I I 1 j f I I l"f I I I l"|~ I II T ~] 8494 '***%%*• ************ CZZ2 ♦y***y»y*y*y*-* »«»*•****••••UIIMMIMI 8493 v/mmii t 11 n it r i t ,t t r 8492 VZZZI 8490 »****••< YV7//M I ■> I t M lii»*••««» ** * < 8491 BARREN 8489 BARREN 8488 Z ^ Z Z 8487 BARREN 8485 8486 8483 8484 BARREN * + **»*****«««*»*1 »•*«••*•••**« • * • • * * * * ' • • « • # • * ♦ *«*•••••« **y*y» y **«y*y*y* * *y* * /» 8482 '.v .v .y .w .v /.’.v.’, y/*y«**y*y.y.y,y*y*y*y 8481 8480 LEGEND: X77 CHORATE ( ^ C A V A T E E 3 PROXIMATE Text-figure Ei. Distribution of dinocyst types, by percent, in Section 15-13, 57 samples. Moderate to high concentrations of spores and pollen were reached in three of the lower eleven samples; the remaining eight sam ples were less productive. Saccate pollen ranged in abundance from 39% to 80% (X=55.7%). Their distribution was relatively constant throughout the section (text- figure 22) and was not related to sediment grain size. Spores occurred in abundances ranging from 43% to 77% (X=57.5%) and their distribution was relatively constant; their abundances were not related to sediment grain size. Spores and pollen were much more abun dant than microplankton in all of the samples. Sections 15 and 16. All three samples studied from Section 15 yielded abundant microplankton (Table 4). Twenty-four species of dinocysts and three species of acritarchs were recovered. One species belonging to the Chlorococcaceae was recovered. Spores and pollen were more abundant than microplankton in the uppermost and lowermost samples; microplankton were more abundant than spores and pollen in the middle sample. The two samples studied from Section 16 contained abundant microplankton (Table 4), consisting of nineteen species of dinocysts and two species of acritarchs. Spores and pollen were much less abundant than in Sec tion 15; microplankton were much more abundant than spores and pollen in both samples. Dinocyst species diversity in Sections 15 and 16 ranged from 10 to 19 species per sample (X=l4; text-figure 23) and did not PERCENT SAMPLE NUMBER 25 50 75 100 | l"1 I "I | I I 'T~l J III I I p T I'T | 8494 8493 8492 Y//77 ?1 8490 Y7V77\ 8491 8489 W / S m 8488 8487 v z m m 1T I 1 I H H H » '»T .V.V.WW.V.W 8485 « . . . _ t 4 « « H 4 4 . «l 8486 Y ///m 8483 Z 7 7 Z 8484I IZZZZ22 4 4 4 I 4,1 8482 ////A* 8481 r 7 Z / 7 7 E 8480 TZ777. LEGEND: YZA SACCATE H OTHER E3SP0RITES POLLEN Text-flgure 32. Spores and pollen distri bution, by percent. In Section 12-13. SAMPLE A DINOCYST SPECIES DIVERSITY SECTION NUMBER 20 8499 - 8498 - 8497 - 8496 - 2550 75 1 0 0 • PERCENT DOMINANCE Text— figure 53. Dinocyst species diversity and dominance, expressed as percent, in Sections 15 and 16. 60 appear to be related to sediment grain size (text-figure 24). Species dominance ranged from 35% to 87% (X=65%) and decreased slightly as sed iment grain size increased. Proximate species were the dominant dinocyst type in Sections 15 and 16, except in Sample 8499 (text-figure 25), in which chorate dinocysts domi nate. The abundance of proximate dinocyst species ranged from 42% to 55% (X=48%) and was not related to sediment grain size (text- figure 26). Chorate species were generally the second most abundant dinocyst type in Sections 15 and 16 (text-figure 25). Chorate species abundance ranged from 10% to 50% (X=29%) and increased as sediment grain size increased (text-figure 26). Cavate species were the least abundant type of dinocysts in all samples except 8498, in which they constituted 40% of all dinocyst species. The abundance of cavate species ranged from 8% to 40% (X=29%) and decreased as sediment grain size increased (text-figure 26). Saccate pollen dominated the miospore spectra in all samples except 8499 (text-figure 27) and ranged in abundance from 37% to 57% (X=49%). Sac cate pollen decreased in abundance as sediment grain size increased (text-figure 28). SEDIMENT A DINOCYST SPECIES DIVERSITY GRAIN feAMPLE 20 15 10 5 0 SIZE NUMBER i i i i i MEDIUM TO COARSE SAND 8499 8497 MEDIUM SAND 8496 FINE 8498 TO MEDIUM 8495 SAND 1 i i 1 I 0 25 50 75 100 SECTIONS 15 AND 16 • PERCENT DOMINANCE Text-figure 24. Dinocyst species diversity and dominace plotted against sediment grain size for Sections IS and 15. PERCENT SAMPLE SECTION NUMBER 0 25 50 75 100 1 i i i i I i i i i | ~i r i t |‘ r i t i i y y / / / / / •*♦•♦**«•••*• 8499 / / / / y y y a .* «*r- «•?*♦.* •«*•*****••*• 16 8498 y *•.*%*;-?.•*!*-•!* « •!« '!* • **«••*«*•••••♦••**♦*• .* » 4 4 4 * * 4 444444C4444444 »* f«444«4444<**44f9444 .•»44444444*9«*«4449<49 . 44*444*44444444*«444 8497 • »444t*444»444«4*44«44 9444«9944*4«44«4»44444 4«444444t44«4»44t4t44 IB 8496 4«4»44*4444«444444444 yy/> iS iS i; V.V.'.V.V.VAV.VA!.VV*! •**,• , * , • • 4' 4««»*44«*444l»»«* 8495 if*444**44««ff44f*4 V///. «4«t444*444444444 LEGEND: VA CHORATE F51 CAVATE Eg3 PROXI MATE Text-figure 25. Types of dinocyst species in Sections 15 and IB, by percent. SEDIMENT PERCENT GRAIN SAMPLE 0 20 40 60 SIZE NUMBER 1 i i i MEDIUM TO CORRSE SRND 8499 MEDIUM 8497 SRND 8496 FINE TO 8498 x > MEDIUM SRND 8495 LEGEND: SECTIONS ▲ X CHORATE DINOCYST SPECIES 15 AND 16 • •/. CAVATE DINOCYST SPECIES □ X PROXIMATE DINOCYST SPECIES Text-figure 2G. Di nocyst types present in Sections 15 and 16, by percent, plotted against sediment grain size. U) PERCENT SAMPLE SECTION NUMBER 0 25 50 75 100 i i i i i 1 i i i I-"] i i '"i i | n r r y 8499 / / / / / / >>> 16 8498 //////// iiiiftill ** 8497 V/////77m ^M■ $ 1 5 8496 ’////Z /z^^^m m 8495 'ZZZZZZZ/ i l i i i l LEGEND: X7A SACCATE POLLEN H OTHER E71 SPORITES Text-figure S7. The distribution of spores and pollen. by percent, in Sections 15 and 16. SEDIMENT PERCENT GRAIN SAMPLE SIZE NUMBER 0 25 50 75 100 MEDIUM TO 1 1 1 1 1 COARSE 01 8499 8497 MEDIUM SAND 8496 FINE 8498 TO MEDIUM 8495 * < SAND SECTIONS 15 AND 16 • SACCATE POLLEN A SPORITES Text-figure 28. The distribution of spores and saccate pollen, by percent, plotted against sediment grain size for Sections 15 66 Spores accounted for from 5% to 20% (X=ll%) of the miospores counted in Sections 15 and 16 (text-figure 27). Spores, like saccate pollen, decreased in abundance as sediment grain size increased (text- figure 28). Sections 17. 18, and 19. Three samples from Section 17 were studied, all of which contained abundant microplankton (Table 5). Twenty-three species of dinocysts, one species of acritarchs and one species belonging to the Chlorococcaceae were recorded. Thirteen percent (3 species) of the dinocysts and all of the acritarchs are reworked. low to moderate concentrations of spores and pollen were recovered from all three samples and their abundances increased from the base to the top of the section. Microplankton were much more abundant than spores and pollen in all samples. The three samples from Section 18 were all productive, two more so than the third (Table 5). Twenty species of dinocysts and two species of acritarchs were recorded. Twenty percent (4 species) of the dinocysts and fifty percent of the acritarchs were reworked. Spores and pollen were present in concentrations ranging from good to poor and their abundance decreased from the base to the top of the sec tion. Microplankton were more abundant than spores and pollen in all samples. Seven samples from Section 19 were studied, all of which contained microplankton (Table 5). Five samples were highly productive; two only 67 moderately so. Thirty-three species of dinocysts, four species of acri tarchs and three species belonging to the Chlorococcales were recorded. Twenty-one percent (7 species) of the dinocysts and twenty-five percent (1 species) of the acritarchs were reworked. Spores and pollen were present in all samples. Microplankton were more abundant than spores and pollen in all but two samples in which spores and pollen were much more plentiful. Maceral analysis indicates that a composite section composed of Sec tions 17, IS, and 19 can be divided into an upper (Unit U) and a lower unit (Unit L). Unit L consists of samples S500 through 8503 and Unit U includes samples 8504-8512. Dinocyst species diversity was 40% higher in Unit L (X=15) than in Unit U (X=ll). The variability of species diversity was much lower in Unit L than in Unit U (text-figure 29). Species diversity decreased as grain size increased (text-figure 30). Species dominance was essentially the same in Unit L (X=6l.4) and Unit U (X=60.3%) of the composite section. However, dominance vari ability was much lower in Unit L than Unit U (text-figure 29). Species dominance increased as sediment grain size increased (text-figure 30). The distribution of dinocyst species types in Section 17, 18 and 19 is shown in text-figure 31. Chorate dinocyst species were much more abun dant, on the average, in Unit L (X=45%) than in Unit U (X=27%). Cho rate dinocysts also were the most frequently counted specimen in Unit L (68%). 68 SECT SAMPLE A PERCENT DOMINANCE UNIT ION 4UHBER 0 10 20 30 40 50 60 70 80 90 100 1 i i i i i i i i i i 8512 8511 8510 U 19 8509 8508 8507 8506 8505 18 8504 8503 L 8502 17 8501 8500 1 1 i > i SECTIONS 5 10 15 20 25 17, 16 AND .19 • SPECIES DIVER1STY Text-figure SB. Dlnocyst species diversity and dominance in Sections 17, IB and 19. SEDIMENT BRAIN SAMPLE A DINOCYST SPECIES DIVERSITY SIZE NUMBER 10 15 20 25 _J__ i I _I_ 85 TO 8505- COARSE SAND 02 8512- SAND FINE TO 8509- I MEDIUM SAND S1LTY FINE 8508- I TO NED SAND 8511- FINE 8504- SRND 8500' 8510- VERT 8507- 8506 FINE 8503- SAND 8502- 8501- I I — r~ -1— 40 60 80 100 SECTIONS 20 17# 18 AND 19 • PERCENT DOMINANCE Text-figure 30. Dinocyst species diversity and dominance plotted against sediment grain size in Sections 17, IB and 19. o\ vo PERCENT SECT SAMPLE ION NUMBER 0 25 50 75 100 J -1 I I I ] T I I I | I r I I "p I T I j «*4*«44»4■ v.v*v. 8512 rZZX WWW 8511 8510 Y77//y)M$m * 4 4 * 4 4 4 4*# *% I « 4 4 • • 4 II 19 «•«««»»*' 8509 44*»t*44»< www\ 8508 WWWi /////,mrnmm 4 4 4 4 *^4^*1 v / i ’ , % ' r 8507 /v /y /m s m M **♦'***#%%*• 8506 y/y/ym m m m ***•*»**■*•*»*• l\ % * » 8505 //rnemmmmm» »-*■«■«« ». 18 8504 v ///p m ® m m XvX*X 8503 '/z ///m z m m V-V.X'.’ 8502 s/Z/Z/y 17 8501 //////z/mwm *4*4*#4#*4*4* 8500 4 #***•• 4 4 4 4 4 4 //////m trnm 4 4 4 4 4 4 • LEGEND: ^ CHORATE O H CAVATE E 3 PROXI MATE Text-figure 31. Dinocyst types present in Sections 17, 18 and IB, by percent. 71 Cavate and proximate dinocyst species are more common in Unit U (X=27% and 46%, respectively) than in Unit L (X-17% and 39%, respectively). The percentage of chorate dinocyst species decreased markedly as sedi ment grain size increased (text-figure 32). Conversely, the percentage of cavate and proximate dinocyst species increased as sediment grain size increased. The saccate pollen were slightly more abundant (text-figure 33) in Unit U (X=32%) than in Unit L (X=26%). The variation in the concen tration of saccate pollen followed the fluctuations of phytoclast in Unit L, but not in Unit U. There was no relationship between sediment grain size and the percent abundance of saccate pollen grains. Spores were more abundant in Unit U (X=17%) than in Unit L (X=9%). Spore distribution was not related to grain size. The Distribution of Reworked Palynomorph General Statement. Reworked palynomorphs occur throughout Sections 3, 17, 18, and 19, which were collected from the La Meseta Formation. Reworked palynomorphs were very rare or totally absent in Section 12-13, 15, and 16 of the Cross Valley Formation. Permo-Triassic Period Stria- titi pollen occur in all sections except Sections 15 and 16. Reworked microplankton, ranging in age from the Middle Jurassic Period (Callovian Age) to the early Eocene Epoch, were recorded from samples of Sec tions 3, 17, 18, and 19. SEDINENT • PERCENT CAVATE DINOCYSTS PERCENT CHORATE DINOCYSTS A PERCENT PROXIMATE DINOCYSTS 6RAIN SAMPLE 0 10 20 30 40 50 60 SIZE NUMBER 0 10 20 30 40 50 60 1____ 1____I____ I____I____I____ I 02 TO 8 5 0 5 - COARSE SRND 88 8 5 1 2 - SRND FINE TO 8 5 0 9 - MEDIUM SRND SILTY FINE 8 5 0 8 - TO NED SRND 8 5 1 1 - FINE 8 5 0 4 - SRND 8 5 0 0 - 8 5 1 0 - VERY 8 5 0 7 - 8 5 0 6 - FINE 8 5 0 3 - SRND 8 5 0 2 - 8 5 0 1 - Text-figure 32. Dinocyst types, by percent. plotted against grain size in Sections 17. IB and 19. 73 PERCENT SECT SAMPLE ION NUMBER 0 25 50 75 100 [■ i i i i i" i t i i | i i i i | r i r i j 8512 //////mmmmm 8511 8510 ^ / / / -V:-'V-'-:-V:V-'-i'X’MvX'X 19 8509 '/////mmmmm 8508 ////mmmmmm 8507 x / / . * J , ♦*.- • • * * * * 8506 ////////M m m m m z 8505 ///mmmmmmmmm IB 8504 '/////m m sm m m m m 8503 8502 '///swmm mmmwm t 17 8501 /~ y ~ / ~j 8500 /////mmmmmm LEGEND: P22 SACCATE H OTHER C^lSPORITES POLLEN Text-figure 33. Spores and pollan distribution, by percent, in Sections 17, IB and IB. 74 Section 3 . Fourteen genera, 17 species, and one subspecies of reworked dinocysts were recovered from Section 3 (Table 14). One acritarch genus and species, as well as specimens of Striatiti were recorded. Fewer than ten specimens were counted in most samples although one sample con tained over 60 specimens. The reworked assemblages above and below the middle sample (sample 8444) of Section 3 differ from each other with regard to the species present, relative species abundance, and ages of the dominant species. The reworked microplankton assemblage in the lower half of Section 3 is dominated by the late Senonian Age-Paleocene Epoch species Palaeoperidi- nium pyrophorum, Spinidinium densispinatum and the ?Albian Age-Paleocene Epoch acritarch Ophiobolus lapidaris. Reworked accessory species occur ring in low frequencies include Aptea securigera. Aptea sp,, Cribroperi- diniuro muderongenBe, Cribroperidinium sp., Cyclonephelium distinctum, Diconodinium cristatum, D. multispinum, Isabelidinium druggii, Palaeo- cystodinium granulatum, Spinidinium lanternum, Spiniferites ramosus subsp. reticulatus and Xylochoarion cf. hacknessense. Specimens of Permo-Triassic Period Striatiti are common in the two low ermost samples, but they are very rare or absent in the remainder of the samples in the lower half of Section 3. The reworked palynomorph assemblage above sample 8444 is dominated by specimens of Striatiti, Aptea securigera, Diconodinium multispinium, D. cristatum, Isabelidinium druggii and Ophiobolus lapidaris. The 75 Table 14. Reworked palynomorphs recovered from Section 3. The age range is shown to the right of each taxa. Taxa ______Age Range______ Aptea securigera Early Aptian Aptea sp. Berriasian-Santonian Cleistosphaeridium anchoriferum Aptian-Cenomanian Cribroperidinium muderongense Berriasian-Aptian Cribroperidinium sp. Portlandian-Campanian Cyclonephelium distineturn Berriasian-Early Maastrichtian Diconodinium cristatum Albian-Cenomanian Diconodinium multispinum Albian-Santonian Dinogymnium cf. curvatum Senonian Isabelidinium druggii Early-Middle Paleocene Isabelidinium pellucidum Paleocene-Early Eocene Odontochitina cf. operculata Hauterivian-Campanian Oligosphaeridium pulcherrium Portlandian-Campanian Ophiobolus lapidaris ?Albian-Paleocene Palaeocystodinium granulatum Late Campanian-Maastrichtian Palaeoperidinium pyrophorum Maastrichtian-L/2 Late Paleocene Spinidinium densispinatum Late Campanian-Paleocene Spinidinium lanternum Senonian Spiniferites ramosus subsp. Barremian-Santonian reticulatus Striatiti Permian-Triassic Xylochoarion cf. hacknessense Callovian 76 ranges of these taxa are totally pre-Campanian Stage except for 1. druggii and 0. lapidaris, which range into the Paleocene Series. Very rare accessory species include Aptea sp., Cleistosphaeridium anchoriferuro, Cribroperidinium sp., Cyclonephelium distinction, Dinogym- niuro cf. curvatum, Isabelidinium pellucidum, Odontochitina cf. opercu- lata, Oligosphaeridium pulcherrium, Palaeoperidinium pyrophorum, Spini dinium lanternum, Spiniferites ramosus subsp. reticulatus. Sections 17, 18, and 19. These three sections are considered together because they were collected above one another on the north side of the Meseta. Nine genera, eight species, and one subspecies of microplankton and specimens of Striatiti were recorded in the three sections (Table 15). Of the microplankton, only Ophiobolus lapidaris, Paleoperi- diniuro pyrophorum and Spinidinium densispinatum range up into the Paleo cene Series. The rest are taxa from the Jurassic-Upper Cretaceous sys tems . The reworked palynomorphs in Sections 17 and 18 include Cyclonephelium distinctum, Diconodinium multispinum, Ophiobolus lapidaris, Palaeoperi dinium pyrophorum, Spiniferites ramosus subsp. reticulatus and Striatiti pollen from the Permo-Triassic Period. Specimens of Ophiobolus lapi daris were the most abundant forms present. Reworked palynomorphs are slightly more abundant in Section 19 than in the other two sections. The oldest taxa occur in Section 19, although forms characteristic of the late Senonian Age-Paleocene Series are also 77 Table 15. Reworked palynomorphs recovered from Sections 17, 18, and 19. The age range is shown to the right of each taxa. Taxa ______Age Range______ Aptea securigera Early Aptian Cribroperidinium edwardsi Early Valanginian-Late Campanian Cribroperidinium sp. Portlandian-Campanian Cyclonephelium distinctum Berriasian-Early Maastrichtian Diconodinium cristatum Albian-Cenomanian Diconodinium multispinum Albian-Santonian Ophiobolus lapidaris ?Albian-Paleocene Palaeoperidinium pyrophorum Maastrichtian-L/2 Late Paleocene Pareodinia sp. Bajocian-Albian Spinidinium densispinatum Late Campanian-Paleocene Spiniferites ramosus subsp. Berriasian-Santonian reticulatus Striatiti Permian-Triassic 78 present. A major increase in abundance of Permo-Triassic Period Stria titi also occurs in Section 19. RESULTS OF THE MACERAL AND TOC ANALYSES General Statement. Macerals were recovered from 69 samples. Fhytoclasts were the dominant macerals, and the protistoclasts were the second most abundant, in all samples except one. Protistoclast were more plentiful in the latter sample. Amorphous infested indeterminate (All) macerals were generally only a minor component of the maceral spectra in which they occurred. In rare instances, they accounted for 25-30% of the total maceral con tent. Scleratoclasts consistently were a relatively minor constituent of the maceral spectra. General Maceral and TOC Analyses of the Sections. Section 3 . Phytoclasts were the dominant macerals in Section 3 (text- figure 34) and varied in abundance from 54% to 100% (X=87%). They were less abundant in the upper half of the section (X=8 l%) than in the lower half (X=89%). Phytoclast distribution was not generally related to sediment grain size. Protistoclasts were the second most common maceral type (text-figure 34) in Section 3 and ranged in abundance from 2% to 25% (X=7.9%). Their concentrations were lower in the upper (X=7.1%) half than in the lower (X=10.4%) half of Section 3. Protistoclast distribution and abundance was not related to sediment grain size. 79 PERCENT SAMPLE NUMBER 0 25 50 75 100 | "i i r i | i t i i"| i ) i i | t i r i j 8456 \//7/////7//mma 8455 V / / / / / / 7 A ^ : - l = — rl 8479 yyyyy//yyy//m 8454' Y//////////7A7* 8478 v/y/y/y/yyzzzm 8477 7/y7777/z//mm 8453 /y/yyy/y/zmm B451 7777/7777771mm 8452 \//t/./7/?/y/7wm 8450 Y/7//777Z/yyym 8448 y 7/y7.7777777m 8449 v//7///7/y/7/m 8447 77/7777/77/7777$ 8476 \77/7/777/777m». 8475 \/77777///7777m 8474 Y//////////7/77k 8446 BARREN 8444 V7/7///7/7777M 8445 1/y/777/Ab/iEE==M LEGENDi EZI PHYTOCLASTS E3 SCLERATOCLASTS H I PROTISTOCLASTS B d l l MACERALS Text-figure 34. Distribution of inaceroib , by percent, in Section 3. e u o n o e s ui ’>ueojed Bq ‘siojbsow >o uo( -;nq|j^8ia S1V833VH IIV S SISVIOOiSIiOV stswiaoivvaias E3 sisvisoiahd Z771 0N3331 mmv///;/777 VA i.sve W////////7/7 /A asva m/////////zz/A oava m//////7 ///zz/. 6SV8 m//////z////Z7. lavs '////////////-/A 29V8 W 777777777777 A E9V8 mm//7 //////77 ?i *9*8 A/777 //7 //77 /A S9*8 /'//V//7 /777 Z/\ 99*8 Y7777777 T77777 , 89*8 ’7 /77 /77777 .7727. Z.9 *8 7777777777777 A ti.*8 V777777 /7777 A Qi.*8 77777777777777 A 69*8 \y///////7 Z77 Z7 , E**8 7^ ’V77 /777 /777 \ 2i.*8 W7777777777777 . EZ.V8 1 i i ii 1 i i i » 1 i i i i 1 t i i i 1 OOI Si. OS S Z 0 aaawriN aidwws iN30d3d 18 82 Scleratoclasts were noted in nine samples of Section 3 and ranged in abundance from 2% to 13% (X=4.8%). The distribution of scleratoclasts was essentially the same in the upper (X=4.3%) and lower (X=5.2%) parts of the section. Scleratoclast distribution was not related to sediment grain size. All macerals were present in approximately one-half of all samples, and ranged in abundance from 2% to 31% (X=9.7%). All macerals were more common in the upper half (X=10.1%) than in the lower half (X=8 .8%) of Section 3. As was the case with most other maceral types in Section 3, the abundance and distribution of All macerals displayed no relationship to sediment grain size. Inertinite was recorded in all but six samples of Section 3 (text- figure 35) and ranged in abundance, relative to total macerals, from 2% to 30% (X-8.0%). Concentrations were higher in the upper half (X=10.6%) than in the lower half (X=6.0%) of the section. Inertinite concentrations were slightly higher in fine grained sediments (text- figure 36). Total organic carbon (TOC) percentages varied from 0.071 to 10.304% (X=0.705%). TOC percentages were not related to sediment grain size. Section 12-13. Phytoclasts were the dominant maceral type in all sam ples (text-figure 37) ranging in abundance from 72% to 100% (X=93%). Phytoclast abundance increased as sediment grain size increased (text- figure 38). PERCENT INERTINITE SAMPLE NUMBER 8456- 8479- 8454- 8478- 8471 - 8453- 8451 - 8452- 8450- 8448 - B449 - 8447 B47B - 8474 - B446- 8444 - 8473- 8469- 8470- 8471 - 8468- 8466- 8464 - 8459- 8460- 8458- Tsxt-flgurs 3B. Ths distribution of Insrtlnits, by psrcsnt. In Boctlon 3. 84 SEDIMENT PERCENT 1NERTINITE GRAIN SAMPLE SIZE NUMBER 10 20 30 _I_ _l_ i ■ PEBBLESTONE 8 4 5 9 - HLU.SHNUiilUf t 8454 - :INE TO NED. B 4? 8- SANDSTONE 8462 - 8464 - 8461 - FINE 8 4 6 0 - 8 4 5 6 - SAND 8 4 5 3 - 8 4 5 2 - AND 8451 - 8 4 5 0 - SANDSTONE 8 4 4 9 - 8 4 4 7 - 8444 - 8 4 7 0 - 84&5 - 8 4 7 5 - VERY 8 4 7 2 - 8 4 6 9 - FINE 8 4 6 8 - 8 4 6 7 - SAND 8 4 6 6 - 8 4 6 5 - AND 8 4 6 3 - 8 4 5 8 - 8 4 4 8 - SANDSTONE 8 4 4 6 - 8 4 4 5 - 8 4 4 3 - 84^4 - SILTSTONE 8 4 7 6 - 8 4 7 9 - HUD 8 4 7 7 - FOSSIL ~ "5*73"- MOOD 8471 - Text-figure 3B. The percent inertlnlte plotted against sediment grain size In Section 3. 85 PERCENT SAMPLE NUMBER 0 25 50 75 100 |' 1 l"T 1 | 1 1 1 1 | 1 1 1 1 j 1 1 1 1 | 8494 V/////////7/77, 8493 '7/777/77/77777' 8492 ^77777777777Mm 8490 '7777777777Z77.Z 8491 /ZZZZZZZZZZZZZZX 8489 1 / 7 7 7 7 7 7 7 7 7 8488 77777/777777777 8487 ZZZZZZZZZZZZZZS 8485 VZZZZZZZZZZZmm 848G 7/7777/7/7777A 8483 /77777777Z7777'± 8484 zzzzzzzzzzzzzzz 8482 7777/777/77777 .1 8481 '777777777777m 8480 '7/77/777/77777, LEGEND: [22 pHYTOCLASTS E S SCLERATOCLASTS H PR0T1ST0CLASTS B All Text-flgure 37. MaceraL distribution in Section 13-13. 86 SEDIMENT PERCENT PHYTOCLASTS BRAIN SAMPLE 25 50 75 100 SIZE NUMBER i MEDIUM 8467 TO VERY 6466 CORRSE SRND WITH 8483 6RRNULES 8482 MEDIUM 8484 TO VERY 6488 CORRSE 8480 SRND 8481 FINE TO MED.SRND 8492 SILT- 8493 STONE TO 8494 VERY 8485 FINE SRND 8490 MUD 8489 Text-flgure 3B. Distribution of pngtoclasts plotted against sediment groin size in Section 32-13. 87 Protistoclasts occurred in only 33% of the samples in Section 12-13 and ranged in abundance from 1% to 13% (X-4.2%). They were most abundant in the upper third of the Bection. Scleratoclasts occurred in 33% of the samples and ranged in abundance from 2% to 13% (X=4.8%). Their distribution was not related to sedi ment grain size. Amorphous infested indeterminate (All) macerals ranged in abundance from 2% to 15% (X=6 .8%) and occurred in 50% of the Section 12-13 samples. All maceral distribution was not related to sediment grain size. Total organic carbon (TOC) ranged in abundance from 0.14% to 6.96% (X=1.24%). Exceedingly high TOC values were obtained from sediments containing carbonized wood clasts (text-figure 39). TOC abundance was not related to sediment grain size. Sections 15 and 16. Phytoclasts were the most abundant macerals in all samples except Sample 8498 (text-figure 40), in which protistoclasts dominated. Phytoclast abundances ranged from 30% to 8 8 % (X=64%) and were more abundant in coarser grained sediments (text-figure 41). Protistoclasts, the second most abundant maceral type, ranged from 12% to 70% (X=34) in abundance (text-figure 40). Protistoclasts abundance decreased as sediment grain size increased (text-figure 41). Sclerato clasts were present only in Sample 8495 and accounted for 6% of the maceral spectrum (text-figure 40). Amorphous infested indeterminate (All) macerals were present in only two samples (text-figure 40), accounting for 20 % of the total macerals in each sample. 88 SEDIMENT PERCENT TOC GRAIN SAMPLE SIZE NUMBER 0.5 1.5 2.0 2.5 3.0 7.0 MEDIUM VERY 848G COARSE SAND 8483 HI TH SRANULES MEDIUM 8484 8488 VERY CORRSE 8480 SAND 8481 SILT- STONE VERY FINE SAND HUD 8489 Text-l1gure 39. Percent TOC plotted ogainst sediment grain size in Section 12-13. PERCENT SAMPLE SECTION NUMBER 0 25 50 75 100 I I 1 I I | l l 1 l | I l ! I | I 1 I i 8499 16 //////z/z////. m 8498 z z z z zmrnmmmmmrn 8497 zzzzzzz/zzwmm 15 8496 ///////////. mm = 8495 '//////// iiiliiiiiiiil 4 ... ______LEGEND: ^ PHYTOCLASTS [ H PROTISTOCLASTS S SCLERATOCLASTS Text-figure 40. The distribution of macerals in Sections 15 and 15, expressed as percents. SEDIMENT PERCENT GRAIN SAMPLE SIZE NUMBER 0 25 50 75 100 1 1 1 1 1 f“T 1 1..1 | 1 1 1 1 | I 1 1 1 | NEDIUN TO COARSE SAND 8499 8497 HEDIUH SAND 8496 FINE 8498 TO MEDIUM 8495 SAND SECTIONS A PERCENT PHYTOCLASTS IS AND 16 • PERCENT PROTISTOCLASTS Text-figure 41. The distribution of phgtoclasts and protistoclasts, in Sections 15 and 16, expressed as a percent and plotted against sediment grain size. 91 Inertinite was particularly abundant in Sections 15 and 16 (text- figure 42). Its abundance, relative to total macerals, ranged from 7% to 123% (X=52%) and increased as sediment grain size increased (text- figure 43). TOC concentrations ranged from 0.13% to 1.49% (X=0.62%). TOC abundance was not related to sediment grain size. Sections 17. 18, and 19. Maceral analysis indicates that the composite section can be divided into an upper (Unit U) and a lower unit (Unit I). Unit L consists of samples 8500 through 8503 and Unit U includes samples 8504-8512. The frequency distribution of the maceral types is shown on Table 5 and the percent distribution is shown on text-figure 44. Phytoclasts were the most abundant maceral type in all samples, accounting for between 59% and 91% of the macerals in each sample. They were more abundant in Unit U (X=69%) and increased in abundance as sedi ment grain size increased (text-figure 45). Protistoclasts were the second most abundant macerals in all samples, constituting between 5% and 37% of each maceral spectra (text-figure 44). They were much more abundant in Unit I (X=29%) than in Unit U (X=l4%), with two exceptions. Protistoclasts accounted for 25% and 23% of the macerals in Samples 8509 and 8511, respectively. Protistoclasts were more abundant, generally, in finer grained sediments (text-figure 45). Scleratoclasts were present in less than half of all samples and never constituted more than 2% of any one maceral spectrum (text-figure 44). Frequencies of seleratoclasts were too low to determine whether their distribution was related to sediment grain size. PERCENT INERTINITE SAMPLE SECTION NUMBER 0 25 50 75 100 125 150 _L _L_ i _I_ I__ 8499 IB 8498 8497 15 8496 8495 Text— figure 42. The distribution of inert inite in Sections 15 and 16, expressed as a percentage with reference to the total maceral assemblage. SEDIMENT PERCENT INERTINITE GRAIN SAMPLE SIZE NUMBER 25 50 75 100 125 150 _L ± __I MEDIUM TO 8499 - CORRSE SRND MEDIUM 8497 SRND 8496 8498 FINE SRND 8495 Text-figure 43. The distribution of inertlnite in Sections IS and 16, expressed as a percentage of the total maceral assemblage and plotted against sediment grain size. PERCENT SECT SAMPLE ION NUMBER 0 25 50 75 100 ~| I I I I [ I I I I "|" I I I I | 1 I I M~{ 8512 8511 8510 m 19 8509 8508 8507 850G ZZ2 8505 18 8504 z z 8503 FZZZ1 8502 [ZZZA 17 8501 U7//A 8500 V 7 7 2 LEGEND: PHYTOCLASTS E H SCLERATOCLASTS PROTISTOCLASTS 153 A ll Text-figure 44, The macerals present in Sections 17, IB and IQ, by percent. SEDIMENT 6RAIN SAMPLE • PERCENT PHYTOCLASTS A PERCENT PROTISTOCLASTS SIZE NUMBER 20 40 60 80 100 i i i i i MEDIUM TO 8 5 0 5 - CORRSE SRND MEDIUM 8 5 1 2 - SRND FINE TO 8 5 0 9 - MEDIUM SRND SILTY FINE 8 5 0 8 - TO MED SRND 8511 - FINE 850 4 - SRND 8 5 0 0 - 8 5 1 0 - VERY 8 5 0 7 - 8 5 0 6 - FINE 8 5 0 3 - SRND 8 5 0 2 - 8 5 0 1 - Text-figure 45. Percent phgtoclasts and protistoclasts plotted against sediment grain size in Sections 17. 18 and 19. VO LTI 96 Amorphous infested indeterminate (All) macerals were generally a minor component of the maceral spectrum in which they occurred (text- figure 44). All macerals were almost twice as abundant in Unit U (X=5.6%) than they were in Unit L (X=3%). The highest concentration of A H macerals occurred in Sample 8511 (17%) of Unit U. The abundance of All macerals was not related to sediment grain size (text-figure 46). Inertinite abundances ranged from 0 to 48%, although most values were less than 10% (text-figure 47). High concentrations occurred in Sam ples 8503 (43%) and 8510 (48%). Inertinite was more abundant in Unit L (X=15%) than in Unit U (X=11.0) and in finer grained sediments (text- figure 46). Total organic carbon (TOC) percentages decreased from 0.116% to 1.167% (Table 5) and were higher in Unit L (X=0.63%) than in Unit U (X=0.4l%). TOC percentages varied inversely with grain size (text- figure 48). PERCENT SEDIMENT f il l MRCERnLS PERCENT INERTINITE 6RR1N SAMPLE SIZE NUMBER 10 20 10 20 30 40 50 MEDIUM TO 8505- COURSE SAND MEDIUH 8512- SRND FINE TO 8509- 62 SAND SILTY FINE 8508- TO MED SAND 8511 - FINE 8504- SRND 8500- 8510- VERT 8507- 8506- FINE 8503- SAND 8502- 8501 - Text-figure 46. Percent All macerals and inertinite plotted against sediment grain size in Sections 17. 18 and 19. 98 PERCENT INERTINITE SECT SAMPLE UNIT ION NUMBER 0 10 20 30 40 50 60 70 80 90 100 1 I i i i : i I i i i 8512 8511 8510 U 19 8509 8508 8507 8506 8505 18 8504 8503 8502 L 17 8501 8500 Text-figure 47. The distribution of Inertinite, by percent, in Sections 17, 18 ond 19. SEDIMENT PERCENT TOC 6RRIN SRMPLE NUMBER 0.2 0.4 0.6 0.8 1.0 1.2 SIZE J I 1 I I I I I I I I I 64 TO 8 5 0 5 - ICORRSE SRND FINE TO MEDIUM SAND SILTY FINE TO MED SRND FINE 8504 SRND 8500 8 5 1 0 - VERY 8 5 0 7 - 8 5 0 6 - FINE 8 5 0 3 - SRND 8 5 0 2 - 8501 - Text-figure 48. Percent TOC plotted against sediment grain size in Sections 17, 18 and 19. to VO INTERPRETATIONS Age Determinations La Meseta Formation. Sections 3, 17, 18 and 19 were collected from the La Meseta Formation (see Appendix B). The stratigraphic ranges of the dinocysts recovered from Section 3 are shown in Tables 6 and 10, whereas Tables 9 and 13 show the dinocyst ranges in Sections 17, 18 and 19. Section 3. The stratigraphically significant taxa in Section 3 (Table 16) are Eocene Epoch or younger in age. The stratigraphic ranges of these taxa are discussed below. Aiora fenestrata sensu Wilson, 1967a, was first reported from an Eocene Epoch assemblage recovered from erratics collected in the McMurdo Sound area (McIntyre and Wilson, 1966; Wilson, 1967a). Archangelsky (1969a) found A. fenestrata in the Eocene Rio Turbio Formation of Argentina and Pothe de Baldis (1966) noted its occurrence in the Lower Tertiary beds of Tierra del Fuego. Occurrences in the middle to upper Eocene Series were reported from DSDP 280 and 281 (Haskell and Wilson, 1975). Kemp (1975) described a sparse dinocyst assemblage from DSDP 270 which included Aiora fenestrata, Areosphaeridium diktyoplokus, Senegalinium asymmetricum and Spinidiniuro macmurdoense. The calcareous greensand from which the dinocysts were recovered yielded a potassium-argon age determination of 26 m.y. (Kemp, 1975). Kemp assigned the dinocyst assemblage to the Oligocene or late Oligocene Epoch (Figure 2, Kemp, 1975) based upon the radiometric age data and the presence in the 100 101 Table 1 6 . The stratigraphically significant taxa recovered from Sec tion 3. The age range is shown to the right of each taxa. Taxa Axe Range Aiora fenestrata sensu Wilson, 1967a Eocene Areosphaeridium diktyoplokus Eocene-Early Oligocene Deflandrea antarctica Eocene Deflandrea cygniformis Middle-Late Eocene Lejeunecysta fallax Middle Eocene to Middle Miocene Phthanoperidinium echinatum Eocene Selenopemphix nephroides Late Middle Eocene to Oligocene Spinidinium macmurdoense Eocene Vozzhennikovia apertura Eocene Vozzhennikovia rotunda Eocene 102 assemblage of Selenopemphix nephroides. This species was formerly con sidered to have a stratigraphic range restricted to the middle to late Oligocene Epoch. S. nephroides has since been reported from the late Eocene Barton Beds of southern England (Bujak, 1980). Williams (pers. comm., 1982) considers these beds, and the base of S. nephroides1 stra tigraphic range to be as old as the late-middle Eocene Epoch. Thus Kemp's (1975) extension of the stratigraphic ranges of the taxa noted above are no longer necessary and probably untenable. Kemp (1975) also reported Aiora fenestrata, Areosphaeridium diktyo plokus . Vozzhennikovia apertura and Senegalinium asymmetricum from Unit 4 of DSDP 274. Firm, diatom-based age determinations indicated that the unit belonged to the Oligocene Series, lack of evidence indi cating reworking and the excellent preservation of the dinocysts taxa were cited as reasons for extending the stratigraphic ranges of the dinocysts noted above. Specimens of Vozzhennikovia apertura and Spinidinium macmurdoense were reported from the overlying Miocene Series, Unit 3. These specimens, however, were considered to be reworked and not indicative of a longer stratigraphic range for V. apertura and S. macmurdoense. The source of these reworked taxa was thought to be the rich Eocene Series dinocyst assemblages encountered in Unit 5 (i.e., the unit underlying Unit 4) of DSDP 274. The presence of a rich Eocene Series dinocyst assemblage below Unit 4 and a reworked assemblage in Unit 3 above Unit 4, suggests reworking during the time of deposition of Unit 4 is certainly possible, if not probable. 103 The presence of reworked, delicate specimens, in varying states of pres ervation, is a widespread phenomenon in and around Antarctica (McIntyre and Wilson, 1966; Wilson, 1967a; Kemp, 1972; Wrenn and Beckman, 1982). The excellent preservational state of Kemp's (1975) specimens does not necessarily preclude reworking in Unit 4. These facts suggest reworking cannot be entirely discounted. The evidence against reworking and in favor of extending the stratigraphic ranges is neither compelling nor conclusive. Hall (1977) assigned the Seymour Island deposits containing A. fenestrata to the Eocene-Oligocene series apparently on the basis of the range extensions proposed by Kemp (1975). Hall's age determination also is considered to be untenable. Considering all of the reported occurrences of A. fenestrata, the evi dence indicates a stratigraphic range restricted to the Eocene Series. Deflandrea antarctica has been reported from McMurdo Sound erratics (McIntyre and Wilson, 1966, as D. aff. bakeri; Wilson, 1967a), DSDP 280 and 283 (Haskell and Wilson, 1975) and from the West Ice Shelf area of Antarctica (Kemp, 1972). In every instance, an Eocene Epoch age was considered probable. Deflandrea cygniformis, first described from the Lower Tertiary Series of Tierra del Fuego (Pothe de Baldis, 1966) was recovered from middle to late Eocene Series strata of DSDP 283 (Haskell and Wilson, 1975). The evidence indicates a middle to late Eocene Epoch age for D. cygniformis. 104 Spinidinimn macmurdoense was first described from the McMurdo Sound area (McIntyre and Wilson, 1966; Wilson, 1967a) and later reported from the Rio Turbio Formation of Argentina (Archangelsky and Fasola, 1971), the West Ice Shelf area, Antarctica (Kemp, 1972), DSDP 280, 282 and 283 and the Nanjemoy Formation of Maryland, USA (Goodman, 1975). All of the reported age assignments fall within the Eocene Epoch, except that in DSDP 282, where a questionable assignment to the Oligocene Epoch was cited. S. macmurdoense was one of the taxa whose range was extended by Kemp (1975; see the discussion above concerning Aiora fenestrata). Hall (1977), apparently accepted Kemp's range extension and assigned the Seymour Island occurrences of S. macmurdoense to the upper Eocene or lower Oligocene Series. As noted above, these range extensions are no longer tenable. Vozzhennikovia apertura and V. rotunda were originally described from the McMurdo Sound erratics (Wilson, 1967a). Occurrences of both species were subsequently reported in cores from the middle to upper Eocene Series of DSDP 280 and 281 (Haskell and Wilson, 1975). Specimens of V. apertura observed in DSDP 283 were considered to belong to the Eocene Series (Haskell and Wilson, 1975), as were reworked specimens from the West Ice Shelf area (Kemp, 1972). Reported occurrences of V. apertura in the Oligocene Series of DSDP 270 and DSDP 274 (Kemp, 1975) are here considered to be reworked. The assignment to the Oligocene Epoch for the Seymour Island specimens of 105 V. apertura (Hall, 1977) is considered to be erroneous (see the discus sion of range extensions with regard to Aiora fenestrata, above). V. rotunda was recovered from the Rio Turbio Formation of the Eocene Series in Argentina and the Loreta Formation in southern Chile (Archan gelsky and Fasola, 1971). The latter formation was considered to be younger than the Rio Turbio Formation, "possibly Oligocene". The age assignment is equivocal. Consideration of the available evidence indicates V. apertura and V. rotunda have a stratigraphic range restricted to the Eocene Series. Areosphaeridium diktyoplokus appears to have attained a worldwide geo graphic distribution during the late Eocene Epoch (Eaton, 1971). Although Haskell and Wilson (1975) reported A. diktyoplokus from the middle Paleocene Series in DSDP 283, Eaton (1971) and Williams (1977) consider this species to have first appeared during the early Eocene Epoch. A. diktyoplokus has been recovered from widely separated localities, including the Eocene Series of Germany (Morgenroth, 1966a), southern England (Eaton, 1971; Bujak, 1976), the Scotian Shelf - Grand Banks (Williams and Brideaux, 1975), Argentina (Archangelsky, 1969b), southern Chile (Cookson and Cranwell, 1967), southeast Australia (Cookson and Eisenack, 1965a), McMurdo Sound (Cranwell, 1964; McIntyre and Wilson, 1966; Wilson, 1967a), DSDP 270 and 274 (Kemp, 1975), DSDP 270 and 274 (Kemp, 1975), the West Ice Shelf area (Kemp, 1972) and DSDP 280-283 (Haskell and Wilson, 1975). 106 A. diktyoplokus has been reported from the lower Oligocene Series of Europe (Maier, 1959) and the northwestern European continental shelf and adjacent areas (Caro, 1977). The evidence indicates that the strati graphic distribution of A. diktyoplokus ranges from the Eocene to lower Oligocene series. Lejeunecysta fallax was originally described from the middle Oligocene Series of Europe (Morgenroth, 1966b). Williams and Bujak (1977) recov ered L. fallax from the Oligocene-middle Miocene Series of the Scotian Shelf and the Grand banks. Williams (1978) assigned specimens recovered from DSDP 370 to the middle Eocene to middle Oligocene Series, The evi dence indicates the stratigraphic distribution of I. fallax ranges from the middle Eocene to middle Miocene Series. Phthanoperidinium echinaturn was described from the Eocene Series Brack- lesham Beds of southern England (Eaton, 1976). Williams (1978) reported P. echinatum from a core in the upper Eocene Series of DSDP 370, whereas Caro (1977) indicates a stratigraphic range from the lower to upper Eocene Series for this species on the northwestern European continental shelf and adjacent areas. P. echinatum has a recognized stratigraphic range confined to the Eocene Series. Selenopemphix nephroides, discussed in conjunction with Aiora fenestrata sensu Wilson 1967a, has a stratigraphic range from the upper middle Eocene Series to the Oligocene Series. 107 Section 3 can be divided into a lower interval (Interval A) between and including Samples 8458 and 8453, and an upper interval (Interval B) including all samples above 8453 (text-figure 49). The base of the stratigraphic ranges of Aiora fenestrata sensu Wilson 1967a, Deflandrea antarctica, Spinidinium macmurdoense, Vozzhennikovia rotunda, V. apertura, Phthanoperidinium echinatum and Areosphaeridium diktyo plokus indicate that Interval A is Eocene Epoch or younger (text- figure 49). Le.jeunecysta fallax, Deflandrea cygniformis and Selenopem- phix nephroides are absent from Interval A, but they are present in the overlying Interval B. The absence of these middle Eocene Epoch or younger taxa suggest that Interval A is older than the middle Eocene Epoch. The combined evidence indicates an age for Interval A equivalent to the early Eocene Epoch. However, a middle or even late Eocene Epoch age cannot be ruled out entirely because environmental, rather than biostratigraphic, factors may account for the absence from Interval A of L. fallax, D. cygniformis and S. nephroides. The presence of Le.jeunecysta fallax and Deflandrea cygniformis indicates the middle Eocene Epoch is the maximum age assignable to Interval B. The presence in Interval B of Selenopemphix nephroides restricts the maximum age to the late-middle Eocene Epoch or younger (text-figure 49). The minimum age for Interval B, the late Eocene Epoch, is established by the top of the stratigraphic ranges of Spinidinium macmurdoense, Voz zhennikovia apertura, V. rotunda and Phthanoperidinium echinatum. The combined ranges of all these taxa indicate a late middle to late Eocene Epoch age for Interval B. m o um um echinatum *1 x a x rotunda “O m Lejeunecysta fallax phthanoper i din din i phthanoper Deflandrea cygniformis Deflandrea antarctlca vozzhennikooia apertura SeIenopemphix nephroides SPtnidinium macmurdoense Aiora fenestrata sensu Uit son Aiora fenestrata sensu Uit AreosphoerJdlum dlktyoplokus ZD m m o Text-flgure 49. The stratigraphic ranges of the etratJgraphically significant taxa in Section 3. 109 The lowermost sample, 8457, is assignable to the Holocene Epoch because it was collected on a modern tidal flat at the base of Section 3. Sample 8457 contains a reworked assemblage derived from coastal outcrops of the upper Senonian (Maastrichtian Stage) to Eocene series. Sections 17, 18 and 19. The stratigraphically significant taxa (Table 17) are no younger than the early Oligocene Epoch. The ranges of most of the stratigraphically significant taxa in Sections 17, 18 and 19 were discussed in conjunction with taxa ranges in Section 3. Spiniferites ramosus subsp. multibrevis was described from the Eocene London Clay of southern England (Davey and Williams, 1966a). Although originally described from the Eocene Series, the species has been reported from the Hauterivian Stage to the Ypresian Stage in England and the Aptian Stage of Germany (Davey and Williams, 1966a). The total stratigraphic distribution ranges from the Lower Cretaceous System (Hau terivian Stage) to middle Eocene Series (Williams and Kidson, 1975). Senegalinium asymmetricum was described from glacial erratics in the McMurdo Sound area of Antarctica (Wilson, 1967a) and an Eocene Epoch age was considered likely for the recovered microplankton flora. Eocene Series occurrences of S. asymmetricum are common in the high southern latitudes, having been reported from Argentina (Archangelsky, 1969), the West Ice Shelf area of Antarctica (Kemp, 1972) and DSDP sites 270, 274, 281 and 283 (Kemp, 1975; Haskell and Wilson, 1975). (The occurrences of specimens of this species in the Oligocene Series reported by Kemp (1975) were considered in conjunction with the stratigraphic ranges of n o Table 17. The stratigraphically significant taxa recovered from Sec tions 17, 18 and 19. The age range is shown to the right of each taxa. Taxa Age Range Aiora fenestrata sensu Wilson, 1967a Eocene Areosphaeridium diktyoplokus Eocene-early Oligocene Deflandrea antarctica Eocene Deflandrea cygniformis Middle-Late Eocene Phthanoperidinium echinatum Eocene Senegalinimn asymmetricum Early Maastrichtian-Eocene Spinidinium macmurdoense Eocene Spiniferites ramosus subsp. multibrevis Late Hauterivian-Middle Eocene Vozzhennikovia apertura Eocene Vozzhennikovia rotunda Eocene Ill taxa in Section 3.) S. asymmetricum has been recovered from the Maas- trichtian Stage on the Grand Banks (Williams and Brideaux, 1975). The total stratigraphic range for S. asymmetricum is from the lower Maas- trichtian Stage to the Eocene Series (Williams and Kidson, 1975). A lower interval (Interval A) and an upper interval (Interval B) can be recognized. Interval A consists of samples 8500 to and including 8507. The base of the stratigraphic ranges of Aiora fenestrata, Deflandrea antarctica, Phthanoperidinium echinaturn, Spinidinium macmurdoenset Voz zhennikovia apertura, V. rotunda and Areosphaeridium diktyoplokus indi cate Interval A is no older than the Eocene Epoch (text-figure 50). The presence of Spiniferites ramosus subsp. multibrevis indicates that Interval A is no younger than the middle Eocene Epoch. Interval A is assigned an age equivalent to the early to middle Eocene Epoch. Interval B consists of samples 8508 through 8512. The presence of Phthanoperidinium echinatum, Spinidinium macmurdoense, Vozzhennikovia apertura and V. rotunda indicates Interval B is no younger than the Eocene Epoch. The presence of Deflandrea cygniformis indicates the age of Interval B is no older than the middle Eocene Epoch and no younger than the late Eocene Epoch. The age assigned to Interval B is equiva lent to the middle to late Eocene Epoch. The Cross Valley Formation. Section 12-13 was collected in Cross Valley, the type locality of the Cross Valley Formation (see Appendix B). The structural complexity, active mass wasting on the valley slopes and the lack of detailed geologic mapping renders biostra- tigraphic interpretation of the Cross Valley samples tenuous at best. 112 SECTIONS i l , 18 & 19 / osyinineir j osyinineir iuiii T a x a mu 11 i breui s breui i 11 mu O x / > / ° "D "D / m Deflandrea cygniformis Areosphaeridium diktyoplokus Deflandrea antarctica Phthanoperidinium echinatum seneyui HI HI seneyui Spinidinium macmurdoense V. rotunda Aiora fenestrata Vozzhennikovia apertura Spiniferites ramosus subsp. y r * OLIGOCENE EARLY ----- > » » * > > > LATE ------r EOCENE MIDDLE ---- X — EARLY ------X X X x x X x LATE PALEOCENE MIDDLE Text-figure SO. The stratigraphic ranges of the stratigraphically significant taxa in Sections 17. 18 and 19. 113 The stratigraphically significant taxa are shown in Table 18. Areos- phaeridium diktyoplokus and Vozzhennikovia rotunda are restricted to the Eocene to lower Oligocene series and Eocene Series, respectively. (See discussion of their stratigraphic range under Section 3, above). Alisocysta circumtabulata was described from the Danian Stage of Cali fornia (Drugg, 1967) and has been subsequently reported on a worldwide basis. It has been noted in the early and middle Paleocene Series on the Scotian Shelf (Williams, 1977; Williams and Bujak, 1977), the Paleo cene Series of the northwestern European continental shelf (Caro, 1977) and the Thanetian Stage of Paris Basin (Gruas-Cavagnetto, 1976). The total stratigraphic range of A. circumtabulata is from the Danian Stage to lower Oligocene Series (Williams and Kidson, 1975). Palaeoperidiniuro pyrophorum was described from the Upper Cretaceous System flints of Saxony (Ehrenberg, 1838). P. pyrophorum has been reported from the Upper Cretaceous System-lower Paleocene Series of Europe and the northwest European continental shelf (Caro, 1977), the Danian Stage of California (Drugg, 1967; as P. basilum), the Paleocene Series of DSDP 283 (Haskell and Wilson, 1975) offshore of Australia and New Zealand, the Danian Stage of Alabama (Drugg, 1970; as P. basilum) and the Paleocene Series of Siberia (Vozzhennikovia, 1967; as Pentagonum marginatum and P. sibericum). The total reported stratigraphic range is from the Maastrichtian Stage to the lower half of the upper Paleocene Series (Williams, 1977). 114 Table 18. The stratigraphically significant taxa recovered from Sec tion 12-13. The age range is shown to the right of each taxa. Taxa ______Age Range______ Alisocysta circumtabulata Danian - Early Oligocene Areosphaeridium diktyoplokus Eocene - Early Oligocene Palaeoperidinium pyrophorum Haastrichtian-I/2 Late Paleocene Paralecaniella indentata Late Cretaceous - Miocene Spinidinium densispinatum Late Campanian - Paleocene Spinidinium essoi Late Cretaceous - Late Oligocene Vozzhennikovia rotunda Eocene 115 Paralecaniella indentata. first described from the Paleocene to Miocene epochs of Australia (Deflandre and Cookson, 1955), attained a cosmopol itan distribution, especially during the Paleogene Period. P. indentata has been reported from the Paleocene Series Aquia Formation in Maryland, U.S.A. (McLean, 1971), the middle Paleocene Series of DSDP 214 (Harris, 1974), the upper Eocene to upper Miocene series of the Grand Banks and the Scotia Shelf (Williams and Bujak, 1977), the ?Paleocene Series of Seymour Island (Hall, 1977), and the Tertiary System of the Gulf of Alaska (Elsik, 1977). Clark and Verdier (1967) noted the presence of P. indentata in the Upper Cretaceous System (Cenomanian Stage-lower Senonian Series) of southern England and McLean (1971) reported this species from the Cretaceous System near Friendly, Maryland, U.S.A. The total stratigraphic range of P. indentata is from the Upper Cretaceous System to upper Miocene Series. Spinidinium densispinatum was described from the Paleocene Series of South Dakota (Stanley, 1965). Williams and Kidson (1975) recognized a late campanian Age to Paleocene Epoch range for this species. Spinidinium essoi was originally reported from the Paleocene Series of Tasmania (Cookson and Eisenack, 1967a). McLean (1971) noted the occur rence of S. essoi in the Upper Cretaceous System of Maryland, whereas Goodman (1975) reported it from the Nanjemoy Formation (lower Eocene Series) of Maryland, U.S.A. Williams (1977) reported that the strati graphic range of S. essoi was from the middle Eocene Series to the lower 116 Oligocene Series. The total reported range is from the Upper Cretaceous System to the lower Oligocene Series. The overlapping ranges of Palaeoperidiniuro pyrophorum, Spinidinium den sispinatum, Alisocysta circumtabulata, S. essoi and P. indentata indi cate a post-Maastrichtian Age, pre-latest Paleocene Epoch age for Sec tion 12-13. However, the presence of Areosphaeridium diktyoplokus and Vozzhennikovia rotunda suggests an age equivalent to the Eocene Epoch or younger. There are two possible interpretations of these data, without proposing (insupportable stratigraphic range extensions of one or more taxa. Sec tion 12-13 samples may in fact belong to the Eocene Series and simply contain many reworked, pre-Eocene Epoch, taxa. An alternative explanation is based upon the presence of numerous fault slivers in Cross Valley (Trautman, 1976). It is possible that the sam ples studied may have been collected unwittingly from a number of fault blocks in the Paleocene Series and the Eocene Series. Thus, Paleocene and Eocene epochs age determinations would be correct, but for the indi vidual samples, rather than for the section as a whole. In the latter scenario, samples 8480-8484 and 8485-8491 would be assigned to the Eocene Series, whereas samples 8483 and 8492-8494 would belong to the Paleocene Series. Insufficient evidence is available to determine which interpretation is correct. 117 7Cross Valley Formation. The samples of Sections 15 and 16 were col lected from the Cape Wiman area, at the north end of Seymour Island (text-figure 3). Trautman (1976) and Elliot and Trautman (1982) included the Cape Wiman deposits in the Cross Valley Formation, whereas Zinsmeister (in press) assigned them to the Sobral Formation. The inclusion of the Cape Wiman deposits in the Cross Valley Formation is provisionally accepted here until additional field and laboratory work can resolve the issue. The stratigraphically significant taxa recovered from Sections 15 and 16 are shown in Table 19. The stratigraphic ranges of Palaeoperidinium pyrophorum, Paralecaniella indentata, Spinidinium densispinatum and Ali- socysta circumtabulata have been discussed with regard to their occur rence in Section 12-13. Ceratiopsis boloniensis was described from the Campo de Gibraltar sec tion in the Upper Cretaceous System of southern Spain (Riegei, 1974). Williams and Kidson (1975) consider the stratigraphic range for C. boloniensis to be from the upper Senonian Series to the Paleocene Series. Ceratiopsis dartmooria was originally described from the Dartmoor Forma tion of Australia (Cookson and Eisenack, 1965b). The formation was con sidered to belong to the Paleocene Series. A subsequent study of type locality material led Stover (1974) to assign an age to the Dartmoor Formation equivalent to the early Eocene Epoch. 118 Table 19. The stratigraphically significant taxa recovered from Sec tions 15 and 16. The age range is shown to the right of each taxa. Section 15: Taxa ______Age Range______ Alisocysta circumtabulata Danian-Early Oligocene Ceratiopsis boloniensis Late Senonian-Paleocene C. dartmooria Late Paleocene-L/2 Early Eocene C. speciosa Paleocene-Early Eocene Palaeocystodinium australinum Early Maastrichtian-Paleocene Palaeoperidinium pyrophorum Maastrichtian-L/2 Late Paleocene Spinidinium densispinatum Late campanian-Paleocene Section 16: Taxa ______Age Range______ Alisocysta circumtabulata Danian-Early Oligocene Ceratiopsis boloniensis Late Senonian-Paleocene Palaeocystodinium australinum Early Maastrichtian-Paleocene Palaeoperidinium pyrophorum Maastrichtian-L/2 Late Paleocene Spinidinium .densispinatum Late campanian-Paleocene 119 Haskell and Wilson (1975) recovered specimens similar to C. dartmooria (reported as Deflandrea cf. D. dartmooria) from DSDP 282 core. A Paleo cene Epoch age was tentatively accepted for Core 282-18. The overall stratigraphic range of C. dartmooria is from the upper Paleocene Series to the lower half of the lower Eocene Series (Stover and Williams, 1977). Ceratiopsis speciosa was first recovered from the upper Paleocene Series of Germany (Alberti, 1959). Subsequent reports of C. speciosa are worldwide in distribution, including the Danian Stage of California, U.S.A. (Drugg, 1967), the lower (?) to middle Paleocene Series of northern Spain (Caro, 1973), the upper Paleocene Series of the north western European continental shelf and adjacent areas (Caro, 1977) and the Paleocene Series Cannonball Member of South Dakota (Stanley, 1965). Gocht (1969) recovered specimens of this species from the lower Eocene Series in the McKelfeld well from northwestern Germany. C. aff. C. speciosa (as Deflandrea aff. speciosa) was reported from DSDP 214 in the Indian Ocean by Harris (1974). The total stratigraphic range of C. speciosa is from the Paleocene Series to the lower Eocene Series. Palaeocystodinium australinum was described from the Paleocene Series Pebble Point Formation of southwest Victoria, Australia (Cookson, 1965). Subsequent planktonic foraminiferal studies indicated a middle Paleocene Epoch age for the Pebble Point Formation (McGowan, 1965, 1968). In addition to occurrences reported from Australia (Cookson, 1965; Deflandre and Cookson, 1955), Haskell and Wilson (1975) recovered 120 P. australinum from OSDP 283 cores dated as being equivalent to the Paleocene Epoch. Harris (1974) reported this species from the middle Paleocene Series at DSDP site 214, in the Indian Ocean. P. aff. australinum has been recovered from the Upper Cretaceous System on Campbell Island, south of New Zealand (Wilson, 1967b) and cores from DSDP 275 on the Campbell Plateau (Wilson, 1975). The reported occur rences indicate that P. australinum was widely distributed in the high southern latitudes during the Maastrichtian Age and the Paleocene Epoch. Further afield, Malloy (1972) found P. australinum to be an important component of Maastrichtian Series assemblages recovered from offshore Gabon, West Africa. Stover and Williams (1977) report the stratigraphic range of P. australinum is limited to the upper Paleocene Series, whereas Wil liams and Kidson (1975) and Williams (1977) consider the stratigraphic range to be from the lower Maastrichtian Stage to the Paleocene Series. The latter range is supported by the studies previously noted. Sections 15 and 16 are assigned to the early late Paleocene Epoch. This is based upon the top of the Btratigraphic ranges of Spinidinium densis- pinatum, Ceratiopsis baloniensis, Palaeocystodinium australinum and Palaeoperidinium pyrophorum and upon the bottom of the ranges of Aliso cysta circumtabulata, Ceratiopsis speciosa, and Ceratiopsis dartmooria (text-figure 51). 121 E 3 SECTIONS E C 3 15 & 16 L. E —* o O 3 O ■p r -p to D a 0 ■p O o c in in 3 L. c 3 o £ > L 3) a 41 O in O o a in — • o -P o |*H CE — EE E 01 o 3 u 3 -P 3 c — 1 — 41 U 1*4 4) o c a L. 0 C T> £ — in ■M ■D ■O u T> E (0 o in in 3 ■p o t. (0 (!) in ■p in 4) c a 3) a in a a o U o 31 o o V O — o — 41 CL m O CL O OLIGOCENE EARLY LATE EOCENE MIDDLE EARLY LATE PALEOCENE MIDDLE _SVL Text-figure 51 Thfe stratigraphic ranges of the .stratigraphical ly significant taxa i n Sections 15 and 16. The distribution of the various aged deposits on Seymour Island is shown in text-figure 52. Reworked Palynomorph Distribution Related to the Regional Geology. Section 3. The important trends to note in the distribution of reworked palynomorphs is a decrease from the base to the top of Section 3 in the abundance of late Senonian Age-Paleocene Epoch taxa and a concomitant increase in the abundance of pre-Campanian Age taxa. Consideration of only the most abundant reworked taxa indicates Sec tion 3 is an example of inverted stratigraphy, where an older reworked palynomorph assemblage overlies a younger reworked assemblage. However, the presence in both assemblages of reworked accessory taxa, repre senting a wide range of geologic ages, indicates a simple inverted stra tigraphy model cannot completely explain the distribution of the reworked palynomorph assemblages. The relatively great abundance of reworked late Senonian Age to Paleo cene Epoch microplankton in the lower part of Section 3 suggests they were directly derived from deposits of the upper Senonian Stage- Paleocene Series. The relative scarcity of pre-Santonian Age micro plankton indicates that either their source beds were poorly exposed at the time the lower beds in Section 3 were deposited or that the relative concentration of the older taxa had been diluted previously by cycling through the Upper Cretaceous System. The sparsity of reworked taxa in the Seymour Island Paleocene Series indicates recycling of pre-Campanian Age taxa did not occur during the Paleocene Epoch. 123 CAPE LEGEND 56°45'W WIMAN EZ3 POST-EOCENE □ EARLY TO LATE EOCENE 16 I EARLY-LATE PALEOCENE I ® UNDIFFERENTIATED PALEOCENE AND EOCENE VM UPPER CRETACEOUS VALLEY ■64°15'S Seymour WEDDELL SEA 56°45’W Text-figure 52. Geologic u p of Seymour Island. i 124 The increase in reworked pre-Campanian Age microplankton from the base to the top of Section 3 indicates better exposures existed in the source area during later periods of erosion and redeposition. Exposures of the late Senonian Stage-early Eocene Series are indicated by the presence of Isabelidinium druggii and I. pellucidum in the upper half of Section 3. The marked increase of Striatiti in the upper part of Section 3 (Unit III of the La Meseta Formation, Elliot and Trautman, 1982) was first noted by Askin and Elliot (in press). The increase was attributed to a change in provenance, erosional exposure of Striatiti-bearing rocks or an increased rate of erosion (Askin and Elliot, in press). Two scenarios can explain the reworked palynofloras. Firstly, older rocks were continually exposed and contributed relatively more reworked palynomorphs while the contribution of younger deposits was decreased. Or, secondly, the provenance of the reworked palynomorphs shifted from exposures of the late Senonian Stage-Paleocene Series to a pre-Campanian Stage source area. Recycling occurred in the Seymour Island area during the early Eocene Epoch and became most active during the middle to late Eocene Epoch. Recycling during the Late Cretaceous Period may have occurred but cannot be substantiated at this time. Sections 17, 18. and 19. The only clear trends noted in these sections were a decrease in the abundance of Ophiobolus lapidaris and a major increase in Striatiti from the base to the top of the sections. The 125 striking increase in the abundance of Striatiti in Section 19 is analo gous to that reported from the upper La Meseta Formation by Askin and Elliot (in press) and confirmed by my observation in Section 3. The influx of Striatiti is widespread in the upper La Meseta Formation. The slightly higher concentration of reworked palynomorphs in Section 19 and the changes upsection in the age of the dominant palynomorphs reflect shifts in provenance or increasing exposure of older rocks due to erosion. Paleoenvironmental Analysis. General Statement. Paleoenvironmental analysis is based upon the results of detailed palynological, maceral, and TOC analyses integrated with a general lithologic examination (Appendix B). Sections 17, 18, and 19. The paleoenvironments of Sections 17, 18, and 19 will be discussed first because the palynological trends noted within these sections provide a base of comparison for the other sections. These sections can be considered to be a stacked composite section for paleoenvironmental analysis. The relatively high protistoclast and low phytoclast concentrations indicate a strong marine influence at the time Unit L sediments were deposited. The high dinocyst species diversity and the low spore and pollen densities noted in the lower unit suggest deposition occurred in an offshore environment. The finer grained sediments and higher TOC 126 concentrations of Unit L indicate a relatively low energy depositional environment. Scott and Kidson (1977) have shown that chorate dinocyst are more com monly associated with low energy depositional environments, whereas cavate dinocyst are more abundant in high energy environments. If sedi ment grain size is considered to be an index of energy in the deposi tional environment, then chorate dinocysts and dinocyst species should be most abundant in finer grained sediments. The predominance of cho rate dinocysts in the finer grained sediments of Unit L support this conclusion. The combined data of the present study suggest that deposition occurred in a low energy offshore marine environment, such as a large bay associ ated with the Seymour Island deltaic complex. Elliot and Trautman (1982) regarded the lowermost beds of the La Meseta Formation (lower part of Section 17) to be prodelta deposits; this interpretation is also possible. Unit U sediments were deposited under more variable and generally much shallower conditions. The higher overall abundance of phytoclasts, the decrease in protistoclasts, the increase in reworked palynomorphs, and the increase in spores and pollen indicate a closer proximity to the source of terrestrial macerals and strandline conditions. The overall increase in sediment grain size and the percentage of cavate and proximate dinocysts suggests shoaling occurred in Unit U. This 127 interpretation is supported by an accompanying decrease in dinocyst spe cies diversity. The overall similarity in species dominance between Units L and U suggest additional factors to proximity of shoreline are involved. The increase in terrestrial influence from the base to the top of the section is punctuated by three events of increased marine influence, represented by Samples 8506 to 8507, 8509 and 8511. These are inter preted as being local transgressions within the deltaic complex. Elliot and Trautman (1982) have interpreted their Units II and III as being tide-dominated delta top and possibly lagoonal deposits. The combined maceral palynological and sedimentological data indicate that Unit U is a shoaling sequence punctuated by minor local transgres sions. This agrees with the interpretations of Elliot and Trautman (1982). Section 3 . The dominance of phytoclasts in all samples of Section 3 indicates a close proximity to a terrestrial source. The marked increase in the abundance of spores from the base to the top of the sec tion indicates that the overall terrestrial influence increased in the same direction. A concomitant decrease in protistoclast abundance, dinocyst species diversity, and chorate species abundance indicates an increasing proximity to shore. Overall shoaling of the depositional environment from the base to the top of the section is further indicated by an increase in the abundance 128 of cavate dinocyst species, reworked palynomorphs, sediment grain size and grain size variabilities. The sedimentary trends suggest a high energy nearshore area, but also an area which was subjected to wide fluctuations in the depositional energy level. Near the base of the section a high energy event occurred which led to the deposition of the pebblestone bed (sample 8459). Palynomorphs were essentially absent (Table 5) from the pebblestone bed, although phytoclasts were present. The energy level was apparently high enough to sweep the less dense palynomorphs through the depositional environment whereas the denser phytoclasts remained. The combined maceral, palynological, and sedimentological data suggest that the lower portion of Section 3 was deposited in a moderate energy marine environment associated with the distal reaches of a delta. Sample 8459, near the base of the section, is a high energy channel deposit, suggesting relatively shallow deposition. Elliot and Trautman (1982) have interpreted comparable beds (their Unit II deposits) as being tide-dominated delta top deposits. The upper portion of the section is interpreted as being lagoonal or back island deposits, where low energy deposition could occur with per iodic interruptions of higher energy storm or splay sedimentation. Elliot and Trautman (1982) considered the upper portion of Section 3 (their Unit III) to be lagoonal beds modified by stream runoff and storm deposits. Palynological and maceral analysis support their conclusions. 129 Section 12-13. The inherent problems encountered with Section 12-13 data relate to the poor sampling control and to the possibility that the samples may be in a mixed chronological order due to faulting in Cross Valley. Although the sequence of deposition may be erroneous, the indi vidual depositional environments still may be elucidated. The high dominance of phytoclasts, relatively low miospore concentra tions, scarcity of microplankton, and the coarse nature of the sediments indicates a nonmarine high energy depositional environment for all but the upper four samples of the section. Elliot and Trautman (1982) interpreted the lower portion of the Cross Valley formation as being distributary channel fill deposits. Palynological and particularly maceral analysis support their interpretations. Although the upper four samples were characterized by high phytoclast concentrations, protistoclasts are more abundant in the lower part of the section. Sporomorphs were much more abundant in the upper four sam ples (X=712) than in the remainder of the samples (X=128) and dino cysts are common. The above data indicate a very near shore, low energy, marine environment subject to a strong terrestrial influence. Deposition within an interdistributary area, as suggested by Elliot and Trautman (1982), seems reasonable. Sections 15 and 16. The abundance of phytoclasts indicates a strong terrestrial influence at the time of deposition. 130 The high abundance of phytoclasts, low abundance of protistoclasts, and the larger sediment grain size in Samples 8496, 8497, and 8499 indicate a higher energy depositional environment than that indicated by the same types of criteria for Samples 8495 and 8498. None of the samples, how ever, are indicative of very high energy deposits (e.g., beach or bar rier island deposits). The overall decrease in abundance of miospores upsection and with sedi ment grain size suggests that the depositional environment was increas ingly isolated from the sporomorph provenance or that the miospores were flushed through the depositional environment. The dominant dinocyst specimens in Samples 8495 through 8498 are two proximate species, Palaeoperidinium pyrophorum and Spinidinium sp. A., which are considered to be inshore forms. Together, these species account for from 34% to 87% of the specimens counted in the four sam ples. The dominant dinocyst species in Sample 8499 also is a proximate form, Spinidinium lanternuro. Other dinocyst species generally occur in very low frequencies suggesting that extraneous taxa are being carried into the near shore depositional environment. The trends in the relationships between dinocyst morphologic type, depo sitional energy, and the implied proximity to the ancient shoreline are just the opposite to those observed in Sections 17-19 and reported by Scott and Kidson (1977) and Goodman (1979). These reverse trends indi cate that the interpretation of these relationships is not always simple or straightforward. Mixing of inshore and offshore dinocyst assemblages 131 by storm action or tidal activity are possibilities which must be con sidered, and perhaps elucidated by maceral analysis. Stratigraphic and sedimentologic data led Elliot and Trautman (1982) to conclude Section 15 sediments were deposited in an interdistributary bay; this study supports their conclusion. Section 16 was interpreted as having been deposited in a high energy delta channel (Elliot and Trautman, 1982). The samples studied herein from Section 16 indicate deposition occurred in a very near shore marine environment but not directly within a distributary channel. An inter distributary bay, into which splay deposits or local channel deposits were introduced may have been the depositional environment. In conclusion, it should be noted that the various depositional environ ments discussed above were not components on one delta. Rather, these deposits probably represent many different periods of deltaic develop ment, as the Seymour Island depocenter shifted along the strike of the paleoshoreline. The resulting deposits form the Seymour Island deltaic complex. Comparison of the Seymour Island and High Southern Latitude Floras The Cross Valley Formation. The in-situ Paleocene Series dinocysts recovered from Sections 15 and 16 (Table 4) are primarily cosmopolitan taxa. Operculodinium bergmannii is the only exception, having been reported previously only from southern South America (Archangelsky, 1969a). Reports of this taxa are too few in number to determine its actual geographic distribution. 132 The dinocyst flora recovered from Section 12-13 also consists predomi nantly of cosmopolitan taxa. The one exception is Vozzhennikovia aper tura , which is encountered rarely in only four samples. The strati graphic and structural complexities of Section 12-13 have been alluded to previously and they must be borne in mind when interpretations are made. The cosmopolitan nature of the early late Paleocene Epoch dinocyst flora indicates that there must have been a contemporaneous marine pathway connecting the Seymour Island area with Europe and North America on the one hand and Australia-New Zealand area on the other hand. A distinct high southern latitude flora did not develop until the Eocene Epoch. La Meseta Formation. The in-situ dinocyst flora of the La Meseta Forma tion can be divided into two groups. The first consists of taxa previ ously reported from widely separated areas of the world. This cosmopol itan group constitutes the bulk of in-situ species recorded from the La Meseta Formation. The second group of dinocysts constitutes a flora whose distribution is limited entirely or primarily to the high southern latitudes. The exis tence of this flora was first recognized by Haskell and Wilson (1975) and by Kemp (1975). The flora has been named the transantarctic flora because of its wide distribution in and around Antarctica (Wrenn and Beckman, 1982). 133 Components of the transantarctic flora (Table 20) have been reported from the Rio Turbio Formation of southern South America (Archangelsky, 1969b), Seymour Island (Hall, 1977), the Ross Ice Shelf Project Site J-9 (Wrenn and Beckman, 1982; Wrenn, in press), the McMurdo Sound area (McIntyre and Wilson, 1966; Wilson, 1967a; Truswell, in press), the northern Ross Sea (Wilson, 1968), Deep Sea Drilling Project (DSDP) sites 270, 274, and 280 to 283 (Kemp, 1975; Haskell and Wilson, 1975), and the West Ice Shelf area (Kemp, 1972). Occurrences outside of the southern high latitudes of components belonging to the transantarctic flora are very rare. Spinidinium mac- murdoense and Vozzhennikovia rotunda have been reported from the lower Eocene Series of Maryland, U.S.A. (Goodman, 1975), the former was very rare and the latter was sparse to abundant. Goodman has since expressed some reservations concerning the correctness of these identifications (pers. comm., 1982). The restricted distribution of the transantarctic flora indicates that the biologic endemism that would characterize Antarctic floras and faunas during later geologic ages was becoming established during the Eocene Epoch. Whether geographic or oceanographic isolation initiated this endemism cannot be determined at this time. The distribution also indicates that there was a seaway connecting the Seymour Island area with the southwest Pacific during the time the La Meseta Formation was deposited. During the Eocene Epoch the transan tarctic flora extended from southernmost South America across West 134 Table 20. The dinocyst species composing the transantarctic flora. Those present on Seymour Island are indicated to the right by an "X". Species Present on Seymour Island Aiora fenestrata sensu Wilson, 1967a X Alterbia Tdistincta Deflandrea antarctica X Deflandrea cygniformis X Deflandrea granulata Deflandrea oebisfeldensis sensu Cookson and Cranwell, 1967 X Spinidinium macmurdoense X Vozzhennikovia apertura X Vozzhennikovia rotunda X Wilsonidinium echinosuturatum 135 Antarctica into the Ross Sea, westward between Australia and Antarctica, and into the West Ice Shelf area (text-figure 53). This distribution supportB the existence of a transantarctic strait connecting the Ross and Weddell seas prior to the opening of the Drake Passage during the late Oligocene-early Miocene Epochs, as suggested by Webb (1978, 1979). Such a strait would have facilitated the dispersal of microplankton, perhaps by means of a circum-East Antarctic current. Source Rock Analysis General Statement. Six samples contained sufficient protistoclasts and phytoclasts (i.e., type-IX kerogen) and TOC to be potential hydrocarbon generators. All six samples were at a very early stage of thermal matu ration and have probably generated very little, if any, oil; certainly no wet or dry gas has been evolved. Nineteen additional samples contained enough Type-II and Type-III ker ogen and TOC to be potential source rocks. All these samples, however, were thermally immature. Section 3 . Sample 8465 was a very fine sand with a TOC content of 0.68%. A miospore color index (MCI) of three indicates the Type-II ker ogen was at or approaching very early thermal maturity. Some liquid hydrocarbons may have been generated. Sample 8476 was a siltstone which yielded 1.17% TOC and contained abun dant Type-II kerogen. A very early thermal maturity was indicated for the organic matter by an MCI of three. 136 RioTurbio Formation * 7 Soymour 170 East ' A n tarctica vV \ McMurdo ifioundAwaf T?H^MSSTS 1 MO Text-figure S3. Hap shoving the location of sites from which components of the transantarctic flora have been reported. The relative positions of the continents are those of the late Eocene according to Firstbrook et al. (1979). Deep Sea Drilling Project localities include sites 270, 274, and 280 through 283 (Kemp, 1975; Haskell and Wilson, 1975). The letters A, B, C, and D represent Wilson's (1968) grab sample stations A452, A459, A461, and A466, respectively. The McMurdo Sound Sediment and Tectonic Studies number one corehole is indicated by the letters MSSTS (Truswell, in press). The trend of the hypothesized transan tarctic strait is shown by the dashed lines. 137 Eleven additional potential source rocks were identified in Section 3, including Samples 8443, 8445, 8455, 8462, 8463, 8467, 8468, 8470, 8475, 8477, and 8479. All samples contained Type-II kerogen except Samples 8445 and 8462, which contained Type-Ill kerogen. All samples were at a pregeneration stage of thermal maturity. Section 12-13. Six samples yielded TOC percentages greater than the source rock minimum of 0.5%. Two samples contained Type-II kerogen and four samples consisted of Type-III kerogen. All samples, however, were thermally immature and hydrocarbon generation had not occurred. Section 16. Sample 8498 was a fine to medium sand with a TOC content of 0.64%. Although the macerals equate to Type-II kerogen, microplankton were the dominant autochthonous organic clasts present. This suggests predominantly liquid, rather than gaseous, hydrocarbons would be gener ated. However, the very early thermal maturity of the organic matter suggests little hydrocarbon generation has actually occurred. Sample 8499 was a medium to very coarse sand with a TOC content of 1.49%. The Type-II kerogen which it contained was slightly mature, as indicated by an MCI of three. Section 17. Sample 8502 was a very fine sand with a TOC content of 0.77%. An MCI of four indicates that the Type-II kerogen in the sample has entered early thermal maturity. Microplankton were relatively abun dant in this sample, suggesting liquid hydrocarbon generation may have been generated. 138 Samples 8500 and 8501 are potential source rocks, but their Type-II kerogen content is thermally immature. Section 18. Sample 8504 is a potential source rock; however, its Type-II kerogen content is at a pregeneration stage of thermal maturity. Section 19. Sample 8506 was a very fine sand with a TOC content of 1.05%. An MCI of three indicates that the Type-II kerogen is slightly mature. Samples 8507 and 8509 are potential source rocks at a pregeneration stage of thermal maturity. Both samples contain Type-II kerogen. Location of Mature Source Rocks. The potential source rocks identified here indicate that the types of organic matter necessary for hydrocarbon generation were deposited in the Seymour Island area during the early to middle Paleogene Period. However, only six of the 70 samples studied were thermally mature enough to generate hydrocarbons. More mature source beds can be anticipated to occur deeper and along depositional dip. The Seymour Island Paleogene deltaic complex pro graded southeastward from the Antarctic Peninsula into the northwestern corner of the proto-Weddell Sea. Mature source beds may occur in the Late Cretaceous or early Paleocene marine deposits over which the del taic complex prograded. Such beds may be found under Seymour Island and in the surrounding offshore areas. Submarine localities would most likely fall along a northwest-southeast trending line through the island. 139 The abundance of icebergs in the Weddell Sea would make drilling from offshore platforms in the Seymour Island area exceedingly costly and hazardous. However, ice free Seymour Island is an ideal drilling plat form for onshore and offshore hydrocarbon exploration. CONCLUSIONS An investigation of the organic-walled microplankton (dinocysts and acritarchs) of the only known outcrops of Lower Tertiary System marine sediments from the Antarctic continent has been completed. Seventy sam ples collected from seven stratigraphic sections through the Paleogene System deltaic complex on Seymour Island, Antarctic Peninsula, were examined. Forty-four dinocyst genera, 75 species, and 5 subspecies were recovered, of which two genera and 10 species are new. Six genera and five species of acritarchs, two genera of Pterospermatales, and two genera and three species belonging to the Chlorococcales also were noted. Maceral, TOC and general lithologic analyses were conducted to obtain additional data applicable to paleoenvironmental interpretations. The dinocyst analysis indicates that the samples studied from the La Meseta Formation are assignable to Eocene Series. Unit A of Sec tion 3 is assigned to the lower Eocene Series (although it may be as young as the late Eocene Epoch). The upper interval (Unit B) is assigned to the upper middle to upper Eocene Series. The samples from Sections 17, 18, and 19 also were collected from the La Meseta Formation and are assignable to the Eocene Series. Two inter vals, Units A and B, were recognized within the composited Sections 17, 18, and 19. The lower Unit A was assigned to the lower to middle Eocene Series whereas the overlying Unit B represents the middle to upper Eocene Series. 140 141 The samples collected from the Cross Valley Formation type section are biostratigraphically unreliable due to known, but unmapped, structural complexities and faulting within the collection area. Therefore, Sec tion 12-13 is assigned to undifferentiated deposits of the Paleocene- Eocene Series. ?Cross Valley Formation outcrops in the Cape Wiman area are represented by Section 15 and 16 samples. The recovered dinocyst floras indicate deposition of the sections occurred during the early late Paleocene Epoch. The relative age relationships between the various sections is shown in text-figure 54. Reworked palynomorphs were widespread in Eocene Series samples. The ages and distribution of the reworked palynomorphs indicated an inverted stratigraphy had been created by the exposure, erosion and subsequent redeposition of continually older deposits. The resulting stratigraphic distribution of reworked specimens is characterized by a primarily post-late Senonian Epoch dinocyst flora overlain by a pre-Campanian Age dinocyst flora. Permo-Triassic Period Striatiti pollen are locally present in the lower part of the sections, but are many times more abun dant in the upper part of the Eocene Series. Combined palynologic, maceral, TOC and sedimentologic data indicate that the Cape Wiman beds of the lower upper Paleocene Series were deposited within an interdistributary bay. 142 t-H LlI EPOCH LATE EOCENE MIDDLE EARLY LATE PALEOCENE MIDDLE Text-figure 54. Relative age relationships between the Lower Tertiary sections. 143 The upper four samples of Section 12-13 from the Cross Valley Formation also were deposited in an interdistributary area. The remainder of the Section 12-13 samples were deposited in a distributary channel. The depositional environments of the La Meseta Formation Section 3 and Sections 17, 18, and 19 display the same overall trend of shoaling from the base to the top of the section. The lower portion of these sections was deposited in a moderate energy delta top environment whereas the overlying beds represent lagoonal and storm or splay deposition on the margins of the deltaic complex. The paleoenvironments represented by the various stratigraphic sections are shown in text-figure 55. The map in text-figure 56 shows the location of the Seymour Island topo graphic profiles and cross-sections shown in text-figure 57. The approximate portions of the island covered by the stratigraphic sections from which study samples were collected are also indicated. (Compare text-figures 56 and 57 with the location map (text-figure 58) of the stratigraphic sections.) The dinocyst floras are composed of cosmopolitan and provincial taxa. The early late Paleocene Epoch dinocyst floras recovered from the ?Cross Valley Formation are primarily cosmopolitan taxa. The dinocyst floras recovered from the La Meseta Formation are charac terized by taxa of the provincial transantarctic flora, including Aiora fenestrata, Deflandrea antarctica, D. cygniformis, D. eobisfeldensis GENERAL DEPOSITIONflL ENVIRONMENT INTER- TIDE DEPOSIT- SECTION DISTR1BUT- DOMINATED IONAL "LUVIAL RRY BACK DELTA LARGE PRO ENERGY CHANNEL BAY ISLAND LR0 O O N A L TOP BAY DELTA LEVEL 17. 18 AND 19 (UNIT L) LON MODERATE 17. 18 AND 19 (UNIT U) 10 HIOH MODERATE 3 (LOVER PORTION) TO HIOH LOv 3 (UPPER PORTION) (OCCASIONALLY HIOH) I M S (TOP 4 SAffl.ES) LON 12*13 (LONER SAMPLES) HIOH IS LON LON 16 [OCCASIONALLY '//A _ HIGH) ... Text-figure SS. The general depositional environments and depositlonal energy level represented by the Lower Tertiary sections. 145 LEGEND SEYMOUR ISLAND CROSS SECTIONS M U LT TRACE SUSPECTED FAULT CADI WIMAN Dl P AND STRIKE HORIZONTAL STRATA ✓ CROSS VALLKY K Hi Text-figure 56. Generalized sap of the northeast corner .of Seynour Island showing fault trends, the attitude of bedding planes, end the location of the cross sections depicted in text-figure 57. (Adapted from Rinaldi et el., 1978.) Scol* 0 100 200 m FAULT SECTION II I— — ____ i ‘1 x , i I ------N I f i -I------FAULT FAULTS J_?__ . •___ 17 - ' •— 11__ . 13, SECTIONS M Text-figure 57. Topographic profiles and cross sections through northeast Seymour Island. The bedding attitude is Indicated by straight solid or dashed lines. Cross section E-F was extrapolated from data and a photograph; it is approximate in all respects. (Adapted from Rinaldi et al., 1978.) 9VI 147 sensu Cookson and Cranwell, 1967, Spinidinium macmurdoense, Vozzhenni kovia apertuna, and V. rotunda. During the Eocene Epoch, the transan tarctic flora extended from southernmost South America and Seymour Island across West Antarctica through the Ross Sea and westward between East Antarctica and Australia to the West Ice Shelf area. The distribu tion of this flora supports the existence of a transantarctic strait between East and West Antarctica during the late Paleogene Period. Twenty-five potential source rocks have been identified by maceral and TOC analyses; most are immature. Six contain Type-II kerogen at a very early stage of thermal maturity. More mature source rocks are to be expected at depth below Seymour Island and offshore along a northwest- southeast trending line running through the island. Sub-Tertiary System deposits may prove to be more mature and richer hydrocarbon source beds. It is concluded that the Seymour Island deposits studied represent the lower upper Paleocene and Eocene Series and that deposition occurred within a deltaic complex. Deltaic development occurred adjacent to a rising cordilleran area which shed increasingly older sediments south eastward into the Seymour Island area. The Seymour Island deltaic com plex developed on the West Antarctic margin of a marine strait which connected the Weddell and Ross Seas during the Eocene Epoch. INDEX OF MICROPLANKTON Species Plate, Figure(s) Page 1. Achomosphaera sp. — -- 174 2. Aiora fenestrata sensu Wilson, 1967 11 11-15 174 3. Alisocysta circumtabulata 14 12-15 177 4. Alterbia sp. A. 7 10, 16-20 178 5. Aptea securigera 8 12-14 181 6. Aptea sp. -- — 182 7. Areosphaeridium diktyoplokus 13 1-13 182 8. Baltisphaeridium ligospinosum 12 9,10 281 9. Botryococcus sp. 16 15 291 10. Ceratiopsis boloniensis 1 1,2 184 11. Ceratiopsis dartmooria 1 5,10 185 12. Ceratiopsis speciosa 1 6,11 186 13. Ceratiopsis striata 1 3,7 187 14. Ceratiopsis sp. -- — 187 15. Cerebrocysta bartonensis 7 13-15 168 16. Chytroeispbaeridia explanata 16 13 189 17. Cleistosphaeridium anchoriferum — — 190 18. Comasphaeridium cometes 9 4,5 282 19. Cometodinium cf. whitei 14 4 191 20. Cribroperidinium edwardsii 8 5-7 192 21. Cribroperidinium muderogense 8 8-10 193 22. Cribroperidinium sp. — — 194 23. Cyclonephelium distinctum 8 11 194 24. Cyclopsiella elliptica 7 5 195 148 149 Species Plate, Figure(s) Page 25. Cyclopsiella trematophora 7 9 196 26. Cymatiosphaera sp. 16 7-9 286 27. Deflandrea antarctica Type I 2 5-11,14 197 28. Deflandrea antarctica Type II 2 12,13,15-17 199 3 1-5 29. Deflandrea cygniformis 4 1-12 201 30. Deflandrea oebisfeldensis sensu 3 10 204 Cookson & Cranwell, 1967 31. Deflandrea cf. phosphoritica 3 6-9 205 32. Deflandrea sp. A. 3 11-19 207 33. Deflandrea sp. 210 34. Diconodinium cristatum 8 1,2 210 35. Diconodinium multispiniun 8 3,4 211 36. Dinogymnium cf. curvatum 6 2 213 37. Cyrea nebulosa 16 14 214 38. Forma-A 6 10-16 215 39. Forma-B 11 7-10 218 40. Hystrichosphaeridium cf. astartes 14 1-3 220 41. Hystrichosphaeridium parvum 9 14 221 42. Hystrichosphaeridium salpingophorum 10 12,13 222 43. Hystrichosphaeridium tubiferum 10 1-3 223 subsp. brevispinium 44. Hystrichosphaeridium sp. A. 10 4-6,10,11 224 45. Hystrichosphaeridium sp. 226 46. Impagidinium dispertitum 227 150 Species Plate, Figure(s) P a g e 47. Impagidinium maculatum 15 2,3,5,6 228 48. Impagidinium victorianum 15 8,9,11,12 229 49. Impagidinium sp. 229 50. Impletosphaeridium sp. A. 9 1-3 230 51. Impletosphaeridium sp. B. 12 4-8 232 52. Impletosphaeridium sp. C. 9 6,7 234 53. Isabelidinium druggii 1 12 236 54. Isabelidinium pellucidum 1 13,14 237 55. Kallosphaeridium cf. capulatum 7 11,12 238 56. Leiofusa jurassica 16 12 283 57. Lejeunecysta fallax 5 3 239 58. Lejeunecysta hyalina 5 4,6 240 59. Lejeunecysta sp. -- — 241 60. Micrhystridium sp. A. 9 10,11 284 61. Odontochitina cf. opreculata 14 10,11 241 62. Oligosphaeridium complex 12 11,12 242 63. Oligosphaeridium pulcherrimum 9 15,16 243 64. Oligosphaeridium sp. — — 244 65. Operculodinium bergmannii 10 7-9 244 14 5-7 66. Ophiobolus lapidaris 16 10 284 67. Palaeocystodinium australinum 6 4,5,7 246 68. Palaeocystodinium golzowense 6 8 247 69. Palaeocystodinium granulatum 6 3,9 248 70. Palaeocystodinium sp. — — 249 151 Species Plate, Figure(s) Page 71. Palaeoperidinium pyrophorum 5 7,8 250 72. Palambages Forma B. (of Manum 16 1,2 289 and Cookson, 1964) 73. Palambages morulosa 16 3 287 74. Palambages Type I 16 4-6 290 75. Paralecaniella indentata 14 9 * 251 76. Pareodinia sp. 6 6 252 77. Phelodinium sp. A 5 1,2 253 78. Pterospermella australiensis 16 11 286 79. Phthanoperidinium echinaturn 2 1-4 255 80. Selenopemphix nephroides 5 5 256 81. Senegalinium asymmetricum 1 4,8,9 257 82. Spinidinium densispinatum 5 12 258 83. Spinidinium essoi 5 14 259 84. Spinidinium lanternum 5 15,16 260 85. Spinidinium macmurdoense 5 13 261 86. Spinidinium sp. A. 5 9-11 262 87. Spinidinium sp. 265 88. Spiniferites cf. cornutus 11 4 266 89. Spiniferites ramosus 12 13-15 267 90. Spiniferites ramosus subsp. 14 8 267 granomembranaceus 91. Spiniferites ramosus subsp. 11 1-3 268 granosus 152 Species Plate. Figure(s) Page 92. Spiniferites ramosus subsp. 12 1-3 269 multibrevis 11 5,6 93. Spiniferites ramosus subsp. 6 1 270 reticulatus 94. Spiniferites sp. 271 95. Tanyosphaeridium xanthiopyxides 9 8,9 271 96. Thalassiphora pelagica 15 10 272 97. Thalassiphora velata 15 1,4,7 274 98. Trigonopyxidia ginella 16 16 275 99. Turbiosphaera filosa 12 16-18 276 100. Veryhachium sp. 285 101. Vozzhennikovia apertura 7 1-4 276 102. Vozzhennikovia rotunda 7 6-8 279 103. Xylochoarion cf. hacknessense 9 12,13 280 REFERENCES Adie, R. J. 1958: Geological investigations in the Falkland Islands Dependen cies since 1940; The Polar Record, v. 9, no. 58, p. 3-17. 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L. and Downie, C. 1966c: Further dinoflagellate cysts from the London Clay; in Davey, R. J . , Downie, C., Sarjeant, W.A.S., and Williams, G. L., Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bul letin of the British Museum (Natural History) Geology, Sup plement 3, p. 215-235. Williams, G. L. and Kidson, E. J. 1975: Biostratigraphy and paleoecology of marine Mesozoic-Cenozoic dinoflagellate cysts; Short course notes, Louisiana State University, May 17-21, 1976, Baton Rouge, Louisiana. Wilson, G. J. 1967a: Some new speices of Lower Tertiary dinoflagellates from McMurdo Sound, Antarctica; New Zealand Journal of Botany, v. 5, p. 57-83. 1967b; Microplankton from the Garden Cove Formation, Campbell Island; New Zealand Journal of Botany, v. 5, p. 223-2A0. 1968: Palynology of some Lower Tertiary coal measures in the Waihao District, south Canterbury, New Zealand; New Zealand Journal of Botany; v. 6, p. 56-62. 1975: Palynology of deep-sea cores from DSDP Site 275, southeast Campbell Plateau; in S. M. White (ed.), Initial Reports of the Deep Sea Drilling Project, 29, p. 1031-1035, 1 pi. 1978: Kaiwaradinium, a new dinoflagellate genus from the Lat Jurassic of North Canterbury, New Zealand; New Zealand Journal of Geology and Geophysics, v. 21, p. 81-84. Wilson, G. J. and Clowes, C. D. 1980: A concise catalogue of organic-walled fossil dinoflagellate genera; Department of Scientific and Industrial Research, Report N.Z.G.S. 92, Lower Hatt, New Zealand, p. 1-199. Wiman, C. 1905: Uber die alttertiaaren Vertebraten der Seymourinsel; Wissenschaftliche Ergebnisse de Schwedischen Sudpolar-Expedition 1901-1903, Stockholm, Bd. 3, Lief. 1, p. 1-37, 8 pis. Wrenn, J. H. In Press: Preliminary palynology of the RISP Site J-9, Ross Sea, Antarctica; Antarctic Journal of the United States. Wrenn, J. H. and Beckman, S. W. 1981: Maceral and total organic carbon analyses of DVDP drill core 11; in L. D. McGinnis (ed.), The Dry Valley Drilling Project, American Geophysical Union, Antarctic Research Series, v. 33, p. 391-402, 1 pi. 171 1982: Maceral, total organic carbon and palynological analyses of Ross Ice Shelf Project Site J9 cores; Science, v. 216, p. 187-189. Zinsmeister, W. J. 1976a: A new genus and species of the gastropod family Struthio loriidae, Antarctodarwinella ellioti, from Seymour Island, Antarctica, Ohio Journal of Science, v. 76, no. 3, p. 111-114. 1976b: Intertidal region and molluscan fauna of Seymour Island, Antarctic Peninsula; Antarctic Journal of the United States, v. 11, no. 4, p. 222-225. 1977: Note on a new occurrence of the Southern Hemisphere apor- rhaid gastropod Struthioptera, Finlay and Marwick on Seymour Island, Antarctica, Journal of Paleontology, v. 51, no. 2, p. 399-404. In Press: Review of the Upper Cretaceous-Lower Tertiary sequence on Seymour Island, Antarctica; Institute of Polar Studies, The Ohio State University, Contribution no. 434, Journal of the Geological Society, London. Zinsmeister, tf. J. and Camacho, H. H. 1982: Late Eocene (to Possibly Earliest Oligocene) Molluscan Fauna of the La Meseta Formation of Seymour Island, Antarctic Pen insula; in C. Craddock (ed.), Antarctic Geoscience, Univer sity of Wisconsin Press, Madison, p. 299-304. Dinocyst Biostratigraphy of Seymour Island, Palmer Peninsula, Antarctica Volume II A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Geology by John Harry Wrenn A.S. William Rainey Harper College, 1972 B.S. Northern Illinois University, 1974 M.S. Northern Illinois University, 1977 August, 1982 APPENDIX A - SYSTEMATIC DESCRIPTIONS Introduction, The life cycle of many dinoflagellates is characterized by alternating vegetative (motile thecae) and encysted (nonmotile dinocyst) stages (Wall and Dale, 1968). Placing fossil dinocysts into classifications based upon living dinoflagellates has proven to be difficult. This is because the morphologies of the theca and the dinocyst are often quite different and because some dinoflagellate species produce two or more morphologically different dinocysts. Also, palynologists generally work only with the encysted stage, whereas neontologists rarely consider the dinocyst in their classifications. Therefore, in this work dinocysts are treated as form taxa and classi fied only to the generic level. Specimen frequencies are noted in each paragraph labeled "Stratigraphic Occurrence." The frequencies are expressed in the following general terms: Abundant - greater than 25 percent Common - between 15 and 25 percent Sparse - between 5 and 15 percent Rare - between 1 and 5 percent Very rare - less than 1 percent 173 174 Division PYRRHOPHYTA Class DINOPHYCEA Fritsch Order PERIDINIALES Haeckel Genus Achomosphaera Evitt, 1963 Achomosphaera sp. Comments.- Specimens of Achomosphaera sp. were encountered very infre quently and in a mediocre state of preservation. The numerous processes are stout, hollow and distally trifurcate. Generally, each primary fur cation is bifurcate itself. All of the processes are trifurcate, sug gesting they are gonal processes. The surface of the central body could not be seen in detail, however, there did not appear to be any parasu- tural markings between the processes. An archeopyle was not observed on any of the specimens studied. Stratigraphic occurrence.- La Meseta Formation; Section 3, very rare in sample 8479; Section 15, very rare in samples 8496 and 8497; Section 16, very rare in sample 8499. Genus Aiora Deflandre and Cookson sensu Wilson, 1967a Aiora fenestrata sensu Wilson, 1967a Plate 11, Figures 11-15 Aiora fenestrata (Deflandre & Cookson) Cookson and Eisenack 1960a, sensu Wilson, 1967a. Comments.- Deflandre and Cookson (1955) established Cannosphaeropsis fenestrata based upon a single dinocyst recovered from the Lower 175 Greensand at Molecap Hill, Gingin, Vest Australia. The type specimen is characterized by a central body which gives rise to numerous solid pro cesses connected distally by flattened and perforated trabeculae (see Deflandre and Cookson, 1955, Plate 3, Figure 2). No mention was made of any type of opening in the central body. Cookson and Eisenack (1960a) designated C. fenestrata Deflandre and Cookson 1955 as the type species of their new genus Aiora. Aiora was differentiated from Cannosphaeropsis because the central body of the former "is not enclosed by an external network" (of trabeculae) as is that of Cannosphaeropsis. Two additional specimens, included within their concept of A. fenestrata, were illustrated by Cookson and Eisenack (1960a, Plate 2, Figures 17-18) and one was designated a hypotype. These specimens were from the Gearle siltstone in the Rough Range South No. 1 bore, Carrovan Basin, West Australia. The central body supports processes which are united distally by flat, perforated expansions of the process shafts. Wilson (1967a) assigned morphologically similar specimens from McMurdo Sound, Antarctica, to Aiora fenestrata (Deflandre and Cookson) Cookson and Eisenack. The presence of an archeopyle in this species was noted for the first time. Wilson (1967a) also drew attention to two diametri cally opposed, free processes arising from "the network of intercon nected processes." Stover and Evitt (1978) pointed out the distinct morphologic difference between the type specimen of Aiora fenestrata from the Lower Greensand 176 at Gingin and the hypotype forms from the Gearle siltstone in the Rough Range South No. 1 bore. These authors restricted A. fenestrata to the morphology of the type specimen from the Lower Greensand and established Balteocysta rotula Stover and Evitt 1978 for the Gearle siltstone speci mens. Presumably, the specimens of Aiora fenestrata described by Wilson (1967a) would fall within B. rotula Stover and Evitt 1978. I believe Aiora fenestrata sensu Wilson 1967a represents yet another genus and species. If the archeopyle is apical in position, the process bases are attached to the central body precingularly not equatorially as in B. rotula. The presence of a characteristic opening and the nature of the ribbon-like processes on Aiora fenestrata sensu Wilson differen tiate it from B. rotula and Aiora fenestrata (Deflandre and Cookson 1955) Cookson and Eisenack 1960a emended Stover and Evitt 1978. The Seymour Island specimens are identical to the illustrations of Aiora fenestrata sensu Wilson 1967a from the McMurdo Sound area, except some specimens clearly exhibit a large, hollow antapical projection. Such a structure is hinted at in the specimen shown in Wilson's (1967a) Figure 37. Other specimens only have the slightest hint of an antapical projection in the form of a small hollow bump. The surface of the distal ribbons are often shogreenate to striate. Dimensions.- Observed range (seven specimens): endocyst length 45-87M (mean 59.4p); endocyst width 38-48|j (mean 42.5}0; trabeculae length 66-108p (mean 82p); trabeculae width 57-110|j (mean 87.4p); endophragm thickness Stratigraphic occurrence.- Section 3, very rare in samples 8443, 8458, 8465, 8467, 8468, and 8469; Section 17, very rare in samples 8500 and 8501. Genus Alisocysta Stover and Evitt, 1978 Alisocysta circumtabulata (Drugg, 1967) Stover and Evitt, 1978 Plate 14, Figures 12-15 EiBenackia circumtabulata Drugg, 1967, Palaeontographica, Abt. B, Vol. 120, p. 15, pi. 1, fig. 12-13. Alisocysta circumtabulata (Drugg, 1967) Stover and Evitt, 1978, Stanford University Publications, Geological Sciences, Vol. 15, p. 16. Comments.- The Seymour Island specimens compare closely with the illus trations of the type specimens described by Drugg (1967). The shape is subrounded to ellipsoidal, usually compressed in an approximately dorsal-ventral orientation. The punctate endophragm is 2-3|J thick. A paratabulation formulae of 4', 6'*, 6c, 5s, IP, 6 1*', I''’' is clearly expressed by low (<10p) membraneous outgrowths of the periphragm. The presence of preapical plates could not be ascertained because free or in place apical operculae were not observed. Dimensions.- Observed range (2 specimens): pericyst length 46-48p (mean 47|J); pericyst width 48-49p (mean 48.5p); endocyst length 37-39p (mean 38|j); endocyst width 4l-43|J (mean 42y). 178 Stratigraphic occurrence.- Section 3, very rare in sample 8464; Sec tion 12-13, very rare in sample 8492; Section 15, very rare in sample 8496, sparse in sample 8497; Section 16, very rare in sample 8498, very rare in sample 8499. Genus Alterbia Lentin and Williams, 1976 Alterbia sp. A. Plate 7, Figures 10, 16-20 Description.- SHAPE Pericyst: Ambitus pentagonal to subelliptical. The epicyst is terminated by a short, truncated horn which is usually concave dis tally. The left antapical horn is always longer than the right horn, which may not be evident at all. The shape of the antapical horns range from a distinct spike to a subrounded, posterior protuberance of the pericyst. The pericyst is broadest in the paracingular area. The ambital outline is distinctly serrate. Endocyst: Ambitus round to subelliptical and characteristically separated from the pericyst. 179 PKRAGMA Periphragm: Smooth to scabbrate or granular and approximately 0.5p thick. Endophragm: Shagreenate to scabbrate. Approximately 1|J thick. PARATABULATION Pericyst: Paratabulation suggested by alignment of short, rounded spines or, more commonly, by denticulate to serrate crests. The paracingular and parasulcal areas are delimited by parallel, ser rate crests. The only definite tabulation is provided by the intercalary archeopyle (2a). Endocyst: Paratabulation clearly indicated only by the 2a interca lary archeopyle. PARACINGULUM The slightly laevoratatory paracingulum is bordered by two parallel denticulate to serrate crests. The offset of the two ends is rarely more than 1/4 the width of the paracingulum. The para cingulum divides the pericyst into the hypocyst and the epicyst. The latter is often twice as high as the hypocyst. The para cingulum is not expressed on the endocyst. 180 PARASULCUS The parasulcus is delimited by parallel denticulate to serrate crests. The crests are less well developed and less continuous than those bordering the paracingulum. The parasulcus is broadest posteriorly and tapers anteriorly, where it runs well up on the epicyst. The parasulcus is not expressed on endocysts. ARCHEOPYLE Both the periarcheopyle and the endoarcheopyle are intercalary. The attenuated 2a operculum is characteristically attached along parasuture H4. Dimensions.- Observed range (10 specimens): pericyst length 51-87M (mean 63.9]j); pericyst width 46-76p(mean 6 1 .Ip); endocyst length 45-66p (mean 51.7m); endocyst width 42-56p (mean 55.5m); archeopyle dimensions (6 specimens): length 16-32m (mean 20.4p); width 16-21M (mean 18.9p); periphragm approximately 0.5p thick; endophragm 0.7 5 -1 .Op thick. Discussion.- Numerous, well preserved specimens of this distinctive spe cies were recovered. The endocyst varies widely in shape and size, which affects the observed relationship between the archeopyle and the epipericoel. The epipericoel is in communication with the exterior through the intercalary archeopyle when the endocyst is circular. Com munication is restricted or totally blocked when the endocyst becomes elongated or when it mimics the outline of the pericyst. 181 The presence of two parallel denticulate to serrate transapical crests is distinctive. The middle of each crest occurs at the apex of the apical horn, where it forms a crescent shaped depression in the overall cyst outline. Comparison with similar species.- The parallel transapical crests dis tinguish this species from all other dinocysts. Stratigraphic occurrence.- Section 3, abundant in samples 8452 and 8478, sparse in samples 8454 and 8477, rare in sample 8451; Section 18, very rare in sample 8503; Section 19, rare in samples 8507 and 8508. Genus Aptea Eisenack (1958) emend. Davey and Verdier, 1974 emend. Dorhofer and Davies, 1980 Aptea securigera Davey and Verdier, 1974 Plate 8, Figures 12-14 Aptea securigera Davey and Verdier, 1974, Palaeontology, v. 17, p. 642-643, pi. 91, figs. 2-3. Comments.- Specimens almost identical to illustration of the type material were encountered in the upper half of the X.a Meseta Formation. The main differences are the greater number of processes located in the central mid-dorsal and mid-ventral areas and the perforations present in some processes. Reworked from Early Cretaceous (Early Aptian) deposits. 182 Dimensions.- (One undamaged specimen): Length 79.7|J; width 91.8p; process length up to 17|J; archeopyle width 68p. Stratigraphic occurrence.- Section 3, sparse in sample 8451, very rare in samples 8447, 8452, 8455, and 8472; Section 19, very rare in sample 8509. Aptea sp. Comments.- Rare, heavily damaged specimens of Aptea were encountered in Section 3. Specific assignment was not possible. Reworked from Creta ceous (Berriasian-Santonian) deposits. Stratigraphic occurrence.- Section 3, very rare in samples 8443, 8458, and 8477. Genus Areosphaeridium Eaton, 1971 Areosphaeridium diktyoplokus (Klumpp, 1953) Eaton, 1971 Plate 13, Figures 1-13 Hystrichosphaeridium diktyoplokus Klumpp, 1953, Palaeontographica, Abt. A., vol. 103, p. 392, pi. 18, figs. 3-7. Areosphaeridium diktyoplokus (Klumpp, 1953) Eaton, 1971, Proc. Second Planktonic Conf., Roma, p. 358, pi. 1, figs. 3-8, pi. 2, figs. 1-6. Comments.- This species is quite common in the La Meseta Formation and exhibits a great range in morphologic variability, due in part to pres ervation. Variability is particularly apparent with regards to process 183 number, length, and width. The development of the distal platform varies greatly; those which appear complete generally have ragged edges. The distal platform is usually supported by a single shaft, though the shaft may also bifurcate or trifurcate along its length. The distal ends may or may not be united by a common platform. Rare specimens bear process complexes. The archeopyle is formed by the loss of a single opercular piece com posed of the apical series of paraplates. Generally, one tabular pro cess is centered on each paraplate. None of the specimens could be allocated to any other species of Areos phaeridium. Dimensions.- Observed range (10 specimens): overall diameter 6l-95p (mean 83.6p); endocyst diameter 49-66|J (mean 54.4p); process length 15-29M (mean 21.7p). Stratigraphic occurrence.- Section 3, rare to abundant in all samples except 8445, 8451-8456, 8477-8479; Section 12-13, very rare in sample 8488; Section 17, abundant in all samples; Section 18, sparse in samples 8503 and very rare in sample 8504; Section 19, abundant in sample 8506, rare in samples 8507 and 8508, very rare in sample 8511. 184 Genus Ceratiopsis Vozzhennikovia, 1963, emend. Bujak et al., 1980 Ceratiopsis boloniensis (Riegel, 1974) Lentin and Williams, 1977b Plate 1, Figures 1, 2 Deflandrea boloniensis Riegel. 1974, Revista Espan. Micropal., Vol. 6, p. 354-355, pi. 1, figs. 6-10. Ceratiopsis boloniensis (Riegel, 1974) Lentin and Williams, 1977b, Bed ford Instit. Oceanog. Rept. Series Bl-R-77-8, p. 20. Comments.- The specimens recovered are identical to illustrations of the type material from southern Spain. Surface sculpture is granular to slightly rugulate and usually aligned longitudinally. C. boloniense had been removed from the genus Ceratiopsis and placed into the genus Senegalinium (Stover and Evitt, 1978). Lentin and Wil liams (1981), however, rejected the transfer of Stover and Evitt (1978) and returned the species boloniense to the genus Ceratiopsis. In a subsequent paper, which had been in press at the time Lentin and Williams (1981) returned the species boloniense to Ceratiopsis, Riegel and Sarjeant (1982) also rejected the attribution of the species bolo niense to the genus Senegalinium. Riegel and Sarjeant (1982), however, reassigned this species to the genus Phelodinium. The transfer of the species boloniensis to Phelodinium is rejected because specimens of this species are often bicavate, rather than 185 cornucavate. The latter is a characteristic of the genus Phelodinium. Three line drawings and one photograph from the type material (Riegel, 1974) clearly illustrate bicavate specimens. The species boloniense is considered herein to belong to the genus Cera tiopsis. Dimensions.- Observed range (7 specimens): pericyst length 108-153|J (mean 109. 7|J); pericyst width 67-83|i (mean 74.9p); endocyst length 47-8lp (mean 65.Ip); endocyst width 6l-83p (mean 74.4p); archeopyle length 18-31|J (mean 24.3p); archeopyle width 28-4lp (mean 39.9p). Stratigraphic occurrence.- Section 15, very rare in samples 8495 and 8496, rare in 8497; Section 16, very rare in sample 8498. Ceratiopsis dartmooria (Cookson and Eisenack, 1965b) Lentin and Williams, 1981 Plate 1, Figures 5, 10 Deflandrea dartmooria Cookson and Eisenack, 1965b, Proc. Roy. Soc. Vic toria, Vol. 79, p. 133-134, pi. 16, fig. 1-2, text-fig. 1. Ceratiopsis dartmooria (Cookson and Eisenack, 1965b) Lentin and Wil liams, 1981, Bedford Inst. Oceanography, Rept. Ser. BI-R-81-12, p. 38. Comments.- Rare specimens identical to illustrations of the type material were recovered. Parasuture lines noted by Cookson and Eisenack (1965b), and discussed more fully by Stover (1974), are present, though faint. 186 Dimensions.- (one complete specimen recovered): Pericyst length 131.6|j; pericyst width 65.6p; endocyst length 56.4p; endocyst width 66.7p; archeopyle height 22.6|j; archeopyle width 32.9p. Stratigraphic occurrence.- Section 3, very rare in sample 8463; Sec tion 15, very rare in samples 8495 and 8497. Ceratiopsis speciosa (Alberti, 1959b) Lentin and Williams, 1977b Plate 1, Figures 6-11 Deflandera speciosa Alberti, 1959b, Hitt. geol. St. Inst. Hamb., Vol. 28, p. 97, pi. 9, figs. 12-13. Ceratiopsis speciosa (Alberti, 1959b) Lentin and Williams, 1977b, Bed ford Inst. Oceanograph. Rept. Ser. BI-R-77-8, p. 21. Comments.- Specimens agree closely with holotype illustrations, except some are slightly smaller. Specimens appear to be fragile as many are highly folded, torn or only fragmentary. Dimensions.- Observed range (3 complete specimens): pericyst length 112-l60p (mean 128.2p); pericyst width 75-95fJ (mean 85.Op); endocyst length 55-66JJ (mean 61.5m )» endocyst width 70-90(J (mean 79.9(j); archeo pyle height 21-26|J (mean 24.2p); archeopyle width 37-4l|j (mean 39.2p). Stratigraphic occurrence.- Section 3, very rare in sample 8457; Sec tion 15, rare in samples 8495 and 8496. * 187 Ceratiopsis striata (Drugg, 1967) . Lentin and Williams, 1977b Plate 1, Figures 3, 7 Deflandrea striata Drugg, 1967, Palaeontographica, Abt. B, Vol. 120, p. 18, pi. 2, figs. 13-14. Ceratiopsis striata (Drugg, 1967), Lentin and Williams, 1977b, Bedford Inst. Oceanogr. Rept. Ser. BI-R-77-8, p. 21. Comments.- Rare specimens recovered which are identical to illustrations of the type material. Host specimens damaged. Dimensions.- (1 complete specimen, telescopically shortened): pericyst length 105.7m ; pericyst width 78.2p; endocyst length 54.5p; endocyst width 69.7m > Stratigraphic occurrence.- Section 3, very rare in sample 8463. Ceratiopsis sp. Comments.- Poorly preserved specimens of Ceratiopsis, unidentifiable to the specific level, where grouped under the genus. Stratigraphic occurrence.- Section 15, very rare in sample 8495. 188 Genus Cerebrocysta Bujak, 1980 Cerebrocysta bartonensis Bujak, 1980 Plate 7, Figures 13-15 Cerebrocysta bartonensis Bujak, 1980, Palaeont. Assoc., Spec. Papers Palaeont., No. 24, p. 42, pi. 13, figs. 4-11. Comments.- Specimens compare closely with the type material illustra tions of Cerebrocysta bartonensis except the sculpture appears to be much coarser and the diameter is slightly larger. Broken specimens are more common than complete forms and often these are ''unrolled11 to form a ragged sculptured strip. The sculpture patterns, approximately 1.5|J high, suggest tabulation, as noted by Bujak (1980). It is possible that this is a new species of Cerebrocysta. However, sufficient specimens, well preserved or otherwise, upon which to judge this speculation were not recovered. Dimensions.- Observed range (2 complete specimens recovered): diameter 29-30|i (mean 28.5|i); wall thickness approximately 1.5p. Stratigraphic occurrence.- Section 15, very rare in samples 8495 and 8497; Section 16, rare in sample 8498. 189 Genus Chytroeisphaeridia (Sarjeant, 1962a) Downie and Sarjeant, 1965 emend. Davey, 1979 Chytroeisphaeridia explanata Bujak, 1980 Plate 16, Figure 13 Chytroeisphaeridia explanata Bujak, 1980, Palaeont. Assoc., Spec. Papers Palaeont., No. 24, p. 44, pi. 13, fig. 13-14. Comments.- Smooth, thin walled, subspherical dinocysts with an apical archeopyle. These forms compare favorably with the description of Chy troeisphaeridia explanata, differing only in their larger size. Davey (1979) demonstrated that the genus Chytroeisphaeridia had a pre- cingular, rather than an apical archeopyle as originally reported (Sar jeant, 1962a). The publication erecting Chytroeisphaeridia explanata (Bujak, 1980), a species with an apical archeopyle, was in press at the time the emendation of the genus was published (Davey, 1979). Conse quently, a species with an apical archeopyle was included in a genus shown to have a precingular archeopyle. Transfer of this species to another genus is warranted; however, such action must be accomplished in a proper publication. Therefore, the species explanata is retained in the genus Chytroeisphaeridia for the purposes of this dissertation. Dimensions.- Observed range (5 specimens): autocyst width 70-107p (mean 85m ); autocyst height (without operculum) 6l-ll4p (mean 87.8p); wall thickness approximately 0.5p. 190 Stratigraphic occurrence.- Section 17, very rare in sample 8502; Section 18, very rare in sample 8503; Section 19, very rare in samples 8506 and 8512. Genus CleistoBphaeridium Davey et al., 1966 CleiBtosphaeridium anchoriferum (Cookson and Eisenack, 1960a) Davey et al., 1966 Hystrickosphaeridium anchoriferum Cookson and Eisenack, 1960a, Micro- paleo., vol. 6, p. 8, pi. 2, fig. 11. Cleistosphaeridium ancoriferum (Cookson and Eisenack, 1960a) Davey et al., 1966, Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 167-168, pi. 9, fig. 1. Comments.- Rare fragmentary specimens encountered in the La Meseta For mation. However, the distinctive processes of this species were clearly visible. The hollow processes (about 8p long) constrict distally and then flare into a recurved, bifurcated termination. The base of the processes, when viewed along the process axis, is donut shaped, empha sizing the hollow structure of the process shaft. Reworked from Cretaceous (Aptian to Cenomanian) deposits. Dimensions.- Processes length: 3.5-5|J. Complete specimens not encoun tered. Stratigraphic occurrence.- Section 3, very rare in sample 8451, rare in sample 8452. 191 Genus Cometodinium Cometodinium cf. whitei (Deflandre and Courteville, 1939) Stover and Evitt, 1978 Plate 14, Figure 4 Baltisphaeridium whitei Deflandre and Courteville, 1939, Bull. Soc. Franc. Microsc., Vol. 8, p. 103, pi. 3, figs. 5*6. Cometodinium ?whitei (Deflandre and Courteville, 1939) Stover and Evitt, 1978, Stanford University Publications, Geological Sciences Vol. 15, p. 227. Comments.- The subcircular central body diameter and the length of the processes on the Seymour Island material is about half that of the type material. Also some of the solid processes exhibit minute bifurcations distally. No archeopyle was observed. Dimensions.- Observed range (5 specimens): central body diameter 23.5-34.78p (mean 30.3p); process length 2-1lp. Stratigraphic occurrence.- Section 3, very rare in samples 8447, 8448, 8458, 8472, 8475, rare in samples 8449, 8450, 8476, 8477, and 8479; Sec tion 12-13, rare in sample 8490; Section 15, very rare in sample 8495; Section 16, very rare in sample 8499; Section 18, very rare in sample 8503; Section 19, very rare in sample 8506, abundant in sam ples 8509 and 8510. 192 Genus Cribroperidinium Neale and Sarjeant, 1962 emend. Davey, 1969a Cribroperidiniuin edwardsii (Cookson and Eisenack, 1958) Davey, 1969a Plate 8, Figures 5-7 Gonyaulax edwardsi Cookson and Eisenack, 1958, Proc. Roy. Soc. Victoria, Vol. 70, p. 32-33, pi. 3, figs. 5-6. Cribroperidinium edwardsii (Cookson and Eisenack, 1958) Davey, 1969a, Bull. Br. Mus. Nat. Hist. (Geol.), Vol. 17, p. 128. Comments.- The rare specimens observed in the La Meseta Formation com pare closely with the illustrations and description of the type material from Australia and New Guinea. The stout, apical horn interrupts the circular outline of this subspherical dinocyst. Autophragm approximately 7p thick. The surface is fine to coarsely granulate. Numerous nontabular, capitate to slightly bifid, short, stout spines are distributed in the paraplate areas. Paraplates delimited by thin, low ridges (<7p high). Short, stiff spines occur on the polar regions. Paracingulum narrow, slightly laevo- rotatory and bordered by low, narrow ridges. Parasulcus broad and bord ered by low ridges. The archeopyle is precingular (3P). Reworked from Cretaceous (Early Valanginian to Late Campanian) deposits. 193 Dimensions.- Body diameter 130)J; apical horn length approximately 28|j; wall thickness 7|J; spine length up to 6p. Stratigraphic occurrence.- Section 19, very rare in sample 8508. Cribroperidinium muderongense (Cookson and Eisenack, 1958) Davey 1969a Plate 8, Figures 8-10 Gonyaulax muderongensis Cookson and Eisenack, 1958, Proc. Roy. Soc. Vic toria, p. 32, pi. 3, figs. 34. Cribroperidinium muderongense (Cookson and Eisenack, 1958) Davey, 1969a, Bull. Br. Mus. Nat. Hist. (Geol.), vol. 17, p. 128. Comments.- The single specimen observed is slightly damaged. It is biconical with a very long, stout apical born. The distal portion of horn is degraded, obscuring the original nature of its tip. Paraplate areas delimited by low ridges or by crenulated membranes. Short, squat spines are present on some ridges. Numerous accessory sutures are present within paraplate areas. The paracingulum is strongly laevorotatory, very narrow and bordered by thin, low membranes (approximately 3p high). The parasulcus is much broader than the paracingulum. The archeopyle is precingular (3P). This specimen has been reworked from Early Cretaceous (Barriasian- Aptian) deposits. 194 Dimensions ■- Overall length 134p; width 85|j; apical horn length 34p; wall thickness approximately 2p thick; spines length less than 3.5|J. Stratigraphic occurrence.- Section 3, very rare in sample 8463. Cribroperidinium sp. Comments.- Occasional specimens were encountered which were too badly damaged or degraded to identify beyond the generic level. All such spe cimens are very dark in color and reworked from Jurassic Cretaceous (Portlandian-Campanian) deposits. Stratigraphic occurrence.- Section 3, rare in samples 8451 and 8475, very rare in samples 8453, 8467, and 8474; Section 18, very rare in sample 8503; Section 19, very rare in sample 8509. Genus Cyclonephelium Deflandre and Cookson, 1955, emend. Stover and Evitt, 1978 Cyclonephelium distinctum Deflandre and Cookson, 1955 Plate 8, Figure 11 Cyclonephelium distinctum Deflandre and Cookson, 1955, Aust. Jl. Mar. Freshw. Res., vol. 6, no. 2, p. 285-286, pi. 2, fig. 14, text- figs. 47-48. Comments.- Rare specimens attributable to C. distinctum were observed in the La Meseta Formation. The compressed subcircular to elliptical out line of these specimens is the same as the type material. 195 The left antapical horn is well developed on some specimens and absent on others. Processes solid and up to lip long. Process terminations acuminate, capitate, bifurcate, and irregular. Processes less numerous in mid dorsal and mid-ventral regions. Apical archeopyle with characteristic zig-zag margin. Attached or free operculae were not observed. These specimens are reworked from (Berriasian to Early Maastrichtian) Cretaceous deposits. Dimensions.- One complete specimen measured: Length (without operculum) 107p; width lOOp; process length up to lip. Stratigraphic occurrence.- Section 3, very rare in samples 8472 and 8478; Section 18, very rare in sample 8503. Genus Cyclopsiella Drugg and Loeblich, 1967 Cyclopsiella elliptica Drugg and Loeblich, 1967 Plate 7, Figure 5 Cyclopsiella elliptica Drugg and Loeblich, 1967, Tulane Studies in Geology, vol. 5, no. 4, p. 190, pi. 3, figs. 1-6; text-fig. 7. Comments.- Rare specimens were observed in the La Meseta Formation. These specimens compare closely to Gulf Coast specimens except the overall dimensions are slightly larger and there are no spines on the 196 surface. The paracingulum is indicated by a fold or low ridge. The parasulcus is not evident. Dimensions.- One specimen measured: length 54p; width 56|j; archeopyle diameter 8|J. Stratigraphic occurrence.- Section 3, very rare in sample 8462. Cyclopsiella trematophora (Cookson and Eisenack, 1967a) Lentin and Williams, 1977b Plate 7, Figure 9 Leiosphaeridia trematophora Cookson and Eisenack, 1967a, Proc. Roy. Soc. Victoria, vol. 80, pt. 1, p. 136, pi. 19, fig. 13. Cyclopsiella trematophora (Cookson and Eisenack, 1967a) Lentin and Wil liams, 1977b, Bedford Inst. Oceanography, Rept. Ser./BI-R-77-8, p. 39. Comments.- Specimens identical to the illustrations of type material from Western Tasmania. Occasional specimens have a granular instead of a smooth rim around the archeopyle. Dimensions.- Observed range (10 specimens): 81-108|J (mean 89.5|j); cir cular opening 12-17M (mean 15.3p). Stratigraphic occurrence.- Section 3, rare in samples 8444, 8457, 8458, 8460-8462, 8467, and 8475, very rare in samples 8443, 8465, 8466, 8469, 8476, and 8478; Section 12-13, very rare in sample 8490; Section 15, very rare in samples 8495 and 8497; Section 17, very rare in all sam ples; Section 19, very rare in sample 8511, rare in sample 8512. 197 Genus Deflandrea Eisenack, 1938 emend. Williams and Downie, 1966c emend. Lentin and Williams, 1976 Deflandrea antarctica Wilson, 1967a Plate 2, Figures 5-17; Plate 3, Figures 1-5 Deflandrea artarctica Wilson. 1967a, N.Z. Jl. Bot., Vol.5, p. 58, 60, figs. 23-24, 26-27. Comments.- Some Seymour Island specimens are identical to illustrations of the type material from McMurdo Sound, Antarctica (Wilson, 1967a). Other specimens deviate with regards to size, overall shape and ornamen tation. Such specimens might be considered separate species in the absence of transitional specimens. Such transitional forms are present in the Seymour Island material, and the observed variability is ascribed to intraspecific morphologic plasticity. A complete description follows because of the deviation from the type material. Description. - For the purposes of data gathering Deflandrea antarctica was separated into two groups, Type I and Type II. The major difference between Types I and II was the presence of well developed paratabulation in the latter, as delineated by clusters of intratabular granules or spines. Type I: Peridinioid dinocyst with a nontabular granular surface. The relatively broad epicystal shoulders form the base of the apical horn, which may taper slightly or markedly before reaching the subrounded, 198 papillae capped termination. In the former case, the overall shape of the horn is subtriangular whereas it is subconical in the latter. The hypocyst varies with regards to its shape, the relationship between the pericyst and the endocyst, and the lateral development of the para- cingular region. Where the transverse development of the paracingulum is marked, it projects well beyond any other portion of the dinocyst. The result is a trapezoidal hypocyst which tapers posteriorly from the projecting paracingulum. The antapex may be flat or indented with two short antapical horns of equal length. The endocyst does not contact the pericyst in specimens with this type of hypocyst, except in the pre- cingular area. Specimens of D. antarctica with a transversely pronounced paracingulum are generally thicker walled than specimens with a more conservative paracingulum. The perihypocyst clings to the endocyst in the postcingular area in spe cimens lacking a broadly developed paracingulum. In such specimens, the hypocyst tapers posteriorly, but from well below the paracingulum. The antapex may be flat or indented with two short antapical horns pro jecting posteriorly. The endocyst is generally circular but may be subelliptical. Its sur face is always more or less granular. The paracingulum may be indicated by slight unornamented folds in the periphragm or more clearly by indentations where it crosses the margins of the dinocyst. The paracingulum is usually broad. 19 9 The parasulcus may be indicated by low unornamented parallel folds in the periphragm, although it is not always clearly delineated. A fla gellar scar is generally present on the right side of the parasulcul region. Faratabulation is sometimes indicated by delicate lines which trace out parasutures on the surface of the pericyst. The surface granules are never arranged in paratabular patterns; they are always nontabular. The intercalary archeopyle is formed by the loss of the 2a paraplate in both the pericyst and endocyst. Archeopyle formulae is 2a/2a. Type II: The comments for D. antarctica Type I apply for Type II except as follows. Surface sculpture ranges from low, round granules to aci- cular spines up to 3|J long. Sculpture is distributed in paratabular clusters, indicating a paratabulation formulae of 4', 3a, 7 1', 4?C, 5' ’', 2 ’"', 2-3S. The paracingulum is clearly defined by low ridges topped with rows of granules. The ridges may be slightly reduced and the granules are absent along the paracingulum adjacent to the parasutures between 3'' -41', 4 ’'-5", 2 ' " - 3 " ' , and 3 ' " and 4'*1. D. antarctica Type II is, on average, slightly smaller than Type I. Transitional Forms: Specimens whose morphology falls between that of Types I and II occur in the same sample preparations. For example, forms with nontabular granules and distinct paracingular ridges capped 200 with granules have been observed. Specimens covered with uniformly dis tributed granules and an overprint of paratabulate granules were also noted. Discussion.- Wilson (1967a) noted the presence of atabulate granules, and sometimes tabulate clusters, on the type material. The presence of widely variable sculpture and overall shape suggests D. antarctica is characterized by the same intraspecific morphological plasticity reported for other species of Deflandrea (see McLean, 1971; Goodman, 1975). Such variability may be due to genetic drift or changing environmental influences. Since the contrasting morphologies were encountered within, as well as between, samples it is assumed that environmental influences were at work. Dimensions.- Observed range: Type I (10 specimens): pericyst height 128-l40p (mean 135.5p); pericyst width 87-101m (mean 94.4m ); endocyst height 67-85p (mean 75.3p); endocyst width 75-85p (mean 80.9m); periar- cheopyle: height 27-43|j (mean 35.7p); periarcheopyle width 44-58p (mean 50.3m ); endoarcheopyle height 26-29p (mean 26.6m ); endoarcheopyle width 49-58p (mean 52.2m )• Type II (10 specimens): pericyst height 99-128p (mean 112m ); pericyst width 73-92m (mean 84.1m ); endocyst height 51-79M (mean 65.3m ); endocyst width 68-83m (mean 75.5m ); periarcheopyle height 29-36m (mean 31.7m ); periarcheopyle width 43-54m (mean 47.2m ); endoarcheopyle height 8-24p (mean 16.7m ); endoarcheopyle width 37-53m (mean 45.5m )> 201 Stratigraphic occurrence.- Type I: Section 3, sparse in sample 8474, rare in samples 8444, 8446, 8449, 8450, 8452, 8458, 8462, 8465, very rare in samples 8443, 8448, 8457, 8460, 8464, 8466, 8468, 8470, 8472, 8475, and 8476; Section 17, rare in all samples; Section 18, very rare in sample 8503, sparse in samples 8504 and 8505; Section 19, rare in sample 8506. Type II: Section 3, rare in samples 8462, 8463, and 8465, very rare in samples 8464, 8468, 8470, and 8474; Section 17, very rare in samples 8500 and 8501; Section 18, sparse in sample 8504. Deflandrea cygniformis Pothe de Baldis, 1966 Plate 4, Figures 1-12 Deflandrea cyniformis Pothe de Baldis, 1966, Ameghiniana, Vol. 4, p. 221, pi. 2, fig. C. Comments.- Many excellently preserved specimens were recovered. A wide range in morphology was noted and documented herein. Some specimens were identical to the illustrations of the type specimen, whereas others resembled D. oebisfeldensis sensu Cookson and Cranwell (1967). Yet other specimens developed large paracingular projections, similar to those described under D. antarctica. The morphologic consequences of these projections are quite important. The degree to which the paracingular projections are developed deter mines the shape of the perihypocyst. The periphragm and endophragm are appressed, or closely juxtaposed, in those specimens with a minimal development of paracingular projections. The shape of the perihypocyst is similar to the shape of the endohypocyst, except for a short 202 posterior extension of the periphragm. The posterior edge of this extension is usually flat. Alternatively, short antapical horns may project from each corner of the periphragm extension. On the other hand, specimens bearing large paracingular projections have a perihypocyst whose shape is distinct from the endohypocyst; the shape of the perihypocyst is usually trapezoidal. In such cases, the peri phragm does not normally contact the endophragm laterally in the hypo- / cystal area. Contact is evident, in ambital view, only in the pre- cingular region. (There probably is dorsal and ventral contact in the hypocystal area because the specimens have been flattened.) Trapezoidal shaped hypocysts may be truncated or bear short antapical horns. The shape of the periepicyst also is dependent upon the configuration of the paracingular region. The long apical horn arises from angular or gently rounded shoulders formed anterior of the paracingulum by the per iphragm. Angular shoulders are usually associated with minor para cingular projections, whereas rounded shoulders are present on specimens with well developed projections. The periepicyst is up to three times as long as the perihypocyst, due primarily to a long apical horn. The shape of the apical horn dictates that at least the apical series of paraplates be long and narrow. Simi larly, the intercalary paraplates can be expected to be rather pro tracted longitudinally. Unfortunately, paratabulation is not indicated on the epicyst, except for the archeopyle. The intercalary archeopyle is long and narrow, as expected, and the length:width ratio (1.0-1.3, n 203 mean 1.1 for n = 9) indicates it is an omegaform or attenuated broad hexa 2a archeopyle. This is at variance with the height:width ratio of <1.0 usually ascribed to the genus Deflandrea (Lentin and Williams, 1975). However, the transverse archeopyle index (Al) and the transverse archeo pyle ratio (AR) confirm that it is a broad hexa 2a archeopyle (.55-.74, mean .64 and 1.3-2.8, mean 1.88, respectively, for n = 9). The biometric conflict arises because the archeopyle is very long and its widest portion falls within the epicystal shoulders. Consequently, a large height:width ratio occurs in a species whose Al and AR indicate it has a standard hexa 2a archeopyle. The thin periphragm may be smooth, scabbrate, or bear uniformly distrib uted granules and/or pits. The thick endophragm is fine to coarsely granular. Dimensions.- Observed range (10 specimens): pericyst length 152-l86p (mean 169.7p); pericyst width 99-122p (mean 108.Op); endocyst length 58-83p (mean 73.2p); endocyst width 75-99p (mean 82.7p). Archeopyle dimension (9 specimens): periarcheopyle length 46-68p (mean 56.7p); periarcheopyle width 4l-58p (mean 49.7p); endoarcheopyle length 14-35p (mean 22.2p); endoarcheopyle width 46-58p (mean 51.9p). Stratigraphic occurrence.- Section 3, abundant in sample 8455, sparse in sample 8478, rare in samples 8456, 8477, and 8479; Section 19, sparse in sample 8508. 204 Deflandrea oebisfeldensis Alberti sensu Cookson and Cranwell, 1967 Plate 3, Figure 10 Deflandrea oebisfeldensis Alberti, 1959b, Geol. Staatsinst. Hamburg, Mitt, Vol. 28, p. 95-96, pi. 8, fig. 10-13. Deflandrea oebisfeldensis Alberti sensu Cookson and Cranwell, 1967, Micropaleo., Vol. 13, no. 2, p. 205, pi. 1, figs. 1-4. Comments.- Cookson and Cranwell (1967) assigned specimens of Deflandrea which they recovered from the Lena Dura Formation of southern Chile to Deflandrea oebisfeldensis Alberti. They included within their concept forms with closely oppressed wall layers and others with widely sepa rated wall layers. Kemp (1975) called attention to the closely oppressed state of the wall layers and concluded the specimens of Cookson and Cranwell (1967) probably represented a species distinct from D. oebisfeldense. The latter is characterized by separated wall layers. Kemp (1975) then assigned similar specimens of Deflandrea recovered from the Ross Sea to D. oebisfeldensis Alberti sensu Cookson and Cranwell. The absence of apical papilla and the conically shaped antapical horns of the Ross Sea specimens were cited as reasons for separating them from D. antarctica. Kemp did, however, recognize the possibility that some of her specimens were variants of the latter species. I concur with Kemp's conclusion that D. oebisfeldensis Alberti sensu Cookson and Cranwell is distinct from D. oebisfeldensis Alberti. 205 However, two of the Lena Dura specimens (Plate 1, figures 3 and 4) fall within my concept of D. antarctica, as probably does the Ross Sea spe cimen illustrated in Plate 1, figure 5 of Kemp (1975). The specimen in Plate 1, figure 2 of Cookson and Cranwell (1967) is dis tinctly different from the other illustrated specimens in that the wall layers are completely separated and the paracingulum is less distinct. The degree to which the paracingular projections are developed cannot be ascertained with any assurance because the lateral edges of the specimen have been cut off. The Seymour Island specimens compare favorably with the specimen in Plate 1, figure 2 of Cookson and Cranwell (1967). This form may be an extreme variant of D. antarctica. An insufficient number of specimens was recovered to confirm or deny this speculation. Dimensions.- Observed range (4 specimens): pericyst length 128-l68p (mean 149|J); pericyst width 91-121|J (mean 104.4p); endocyst length 64-91*J (mean 69.7|j); endocyst width 48-90p (mean 73.5p). Stratigraphic occurrence.- Section 3, sparse in sample 8453, very rare in samples 8474, 8476, and 8479; Section 19, very rare in sample 8508. Deflandrea cf. phosphoritica Eisenack, 1938 Plate 3, Figures 6-9 Deflandrea phosphoritica Eisenack, 1938, Schr. phys. -okon. Ges. Konigsb., Vol. 70, p. 187, fig. 6. 206 Comments.- Morphologic variation was pronounced in the La Meseta specimens. The specimens differ from illustrations of the type material in that the lateral expansions of the paracingular area are generally absent and the sides of the hypocyst are less posteriorly convergent than is usual. The 2a intercalary archeopyle is generally more dorsally situated than is often the case in D. phosphoritica. Many of the speci mens illustrated in the literature appear to have an apically situated endoarcheopyle, even though it is formed by the loss of the 2a interca lary paraplate. The sculpture on the periphragm varies from scabbrate to granular; the latter may be tabular or nontabular. Rare specimens exhibited faint parasuture lines similar to those reported on C. dartmooria by Stover (1974) and D. antarctica (in this report). Dimension.- Observed range (10 specimens): pericyst length 95-113p (mean 104.7p); pericyst width 68-85p (mean 75.8p); endocyst length 51-62|J (mean 56.2p); endocyst width 62-79y (mean 68.9|j); periarcheopyle height 30-38p (mean 29.7jj); periarcheopyle width 37-53p (mean 39.5p); endoarcheopyle height 11-24(J (mean 16.2jj); endoarcheopyle width 35-47p (mean 38.3p). Stratigraphic occurrence.- Section 3, sparse in sample 8462, rare in sample 8463, very rare in samples 8464 and 8465. 207 Deflandrea sp. A. Plate 3, Figures 11-19 Description.- SHAPE Bicavate peridinioid dinocyst with short antapical horns or a trun cated, flat antapex. Apical horn may be short or long. Para- cingulum slightly laevoratatory;. longitudinal offset approximately the width of the paracingulum. Parasulcus indicated by a broad depression on the hypocyst which widens posteriorly. Endocyst ambitus subcircular to subpentagonal. PHRAGMA Periphragm thin (<0.5|j), granular, possibly reticulate and divided into distinct paraplates. Paraplates delimited by pandasutural striae which may be up to 17|J wide. The paraplates may be granular or bear a reticulation of low ridges with scattered grana or pores (trichocyst pores?) within the reticulation. (Whether the features are grana or pores could not be determined with light microscopy; resolution of the matter must await SEM investigation, if addi tional sample material can be obtained.) The endophragm is gran ular and nontabulate. 208 PARATABULATION Pandasutural striae are generally well developed, even crossing the paracingulum in some specimens, and delineate a distinct paratabu- lation. The paratabulation formula is 4', ?3a, 7 1', ?3C, S 1'', 2'l,,, ?5S. A flagellar scar is present in the parasulcal area. PARACINGULUM The paracingulum is incised to a greater or lesser degree and bord ered by low, denticulate ridges. The reticulation observed within the paraplate areas is present within the paracingulum, though less well developed. The paracingulum may be divided into paraplates by pandasutural striae, although this was rarely observed. PARASULCUS The parasulcus is expressed as a posteriorly broadening depression bordered by low denticulate ridges. Pandasutural striae delineate up to ?5 parasulcal plates. A flagellar scar is usually present. ARCHEOPYLE The intercalary archeopyle is a broad hexa 2a of Type I/I; some specimens, however, suggest a Type I/3I archeopyle (originally sug gested to me by W. E. Evitt, 1981). It has not been possible to determine whether or not both types are present because so few spe cimens were recovered. The apparent I/3I may be the result of the operculum detaching by tearing through paraplate 2a posterior of and subparallel to parasuture HI. 209 Free broad bexa 2a operculae bearing pandasutural striae along par- asutures H2-H6 have been observed. No free la or 3a paraplates have been observed, nor have operculae composed of paraplates la, 2a, and 3a. Discussion and comparison with similar forms.- The distinctive charac teristics of this species of Deflandrea are the presence of pandasutural striae and the reticulate, possibly porate, intraplate areas. Very faint and scattered pandasutural striae have been observed on D. phosphoritica (unpublished data) but certainly never so distinctly and completely developed. The flat truncated antapex observed on some specimens is similar to that of D. antarctica. The overall shapes of D. antarctica and D. sp. A. are similar, but the surface sculpture and consistently thinner endophragm of the latter clearly separate these species. Dimensions.- Observed range (6 specimens): pericyst length 81-110p (mean 94.2|j); pericyst width 68-77|J (mean 72.Ip); endocyst length 51-80p (mean 63.4p); endocyst width 50-76p (mean 65.6p); endoarcheopyle height 12-22|J (mean 15.2p); endoarcheopyle width 34-48p (mean 4l.8|j). Periar- cheopyle (1 specimen measurable): length 27.5p; width 46.2p. Stratigraphic occurrence.- Section 3, rare in sample 8553; Section 19, very rare in samples 8511 and 8512. 210 Deflandrea sp. Comments.- Specimens of Deflandrea were often recovered which could not be specifically identified. Usually identification was inhibited by extreme folding or fragmentation of the periphragm. Other specimens had been too highly degraded biologically or chemically for a firm specific assignation. Stratigraphic occurrence.- Section 3, abundant in sample 8455, common in sample 8454, sparse in samples 8451, 8453, 8462, and 8478, rare in sam ples 8457, 8458, 8463, 8465, 8478-8477, and 8479, very rare in samples 8443, 8456, 8464, 8466, 8467, 8468, and 8479; Section 12-13, sparse in sample 8486, rare in sample 8493; Section 17, very rare in samples 8501 and 8502; Section 18, very rare in samples 8503 and 8504; Section 19, sparse in sample 8507, rare in sample 8512, very rare in samples 8508 and 8509. Genus Diconodinium Eisenack and Cookson, 1960 emend. Morgan, 1977 Diconodinium cristatum Cookson and Eisenack, 1974 emend. Morgan, 1977 Plate 8, Figures 1, 2 Diconodinium cristatum Cookson and Eisenack, 1974, Palaeontographica, Abt. B, vol. 148, p. 77, pi. 24, figs. 3, 5. Diconodinium cristatum Cookson and Eisenack, 1974, emend. Morgan, 1977, Palynology, vol. 1, p. 126-127, pi. 1, fig. 3. 211 Comments.- The La Meseta Formation samples exhibit the diagnostic antapical "keel" discussed at length by Morgan (1977). Surface sculp ture ranges from fine to coarse granules. Paracingulum bordered by low ridges capped with granules or minute rounded spines. Parasulcus broad, tapering antapically and bordered on each side by a low ridge. Archeopyle intercalary. Paraplates suggested by low ridges. Reworked from Cretaceous (Albian-Cenomanian) deposits. Dimensions.- Observed range (4 specimens): length 71.5-105.6p (mean 84.6p); width 40.7-71.5p (mean 55.3p). Stratigraphic occurrence.- Section 3, rare in samples 8451, 8477, and 8479, very rare in samples 8455, 8472, 8476, and 8478; Section 19, very rare in sample 8508. Diconodinium multispinum (Deflandre and Cookson, 1955) Eisenack and Cookson, 1960 emend. Morgan, 1977 Plate 8, Figures 3, 4 Palaeohystrichophora multispina Deflandre and Cookson, 1955, J. Mar. Freshw. Res., vol. 6, p. 257, pi. 1, fig. 5. Diconodinium multispinum (Deflandre and Cookson, 1955) Eisenack and Cookson, 1963, Proc. Roy. Soc. Victoria, vol. 72, p. 3. 212 Diconodinium multispinum (Deflandre and Cookson, 1955) Eisenack and Cookson, 1963, emend. Morgan 1977, Palynology, vol. 1, p. 127-128, pi. 1, figs. 1, 4, 6, 8. Comments; The genus Diconodinium has been discussed at length in a detailed paper by Morgan (1977). Specimens of D. multispinum recovered from the La Maseta Formation agree completely with the emended diagnosis of Morgan (1977). Sculpture varies from granules to capitate or truncated spines. An intercalary archeopyle with an attached operculum was observed on a few specimens. Reworked from Cretaceous (Albian-Santonian) deposits. Dimensions.- Observed range (seven specimens): length 69-106p (86p mean); width 37-68p (54|J mean); spines less than 2y. Stratigraphic occurrence.- Section 3, sparse in sample 8451, rare in sample 8450, very rare in samples 8443, 8448, 8449, 8455, 8458, 8465, 8468, 8475, 8476, 8478, and 8479; Section 17, very rare in samples 8501 and 8502; Section 19, very rare in samples 8506, 8507, and 8509. 213 Dinogymnium Evitt et al., 1967 Dinogymnium cf. curvaturo (Vozzhennikovia, 1967) Lentin and Williams, 1973 Plate 6, Figure 2 Gymnodinium curvatum Vozzhennikovia, 1967, Akad. Nauk SSSR, Sib. Otd., Inst. Geol. Geofiz., Tr., R. Lees, Trans., W. A. S. Sarjeant, ed.: Boston Spa Yorkshire, England, Natl. Lending Library Sci. Tech., 1971, p. 61-62, PI. I, figs. 10-12; pi. IV, figs. 2-3. Pinogmnium curvatum (Vozzhennikovia, 1967) Lentin and Williams, 1973, Geol. Sur. Canada, Paper No. 73-42, p. 48. Comments.- The single specimen recovered shares some morphological attributes with both Dinogymnium acuminatum and D. curvatum. The speci men's overall dimensions fall within the ranges of both species and the presence of granular surface sculpture which continues across the para- cingular area is common to both species. D. acuminatum generally lacks granulation at the poles and its para- cingular margins are relatively smooth. In contrast, the Seymour Island specimen is granular all over and its distorted paracingular margin in somewhat scalloped. These are features characteristic of D. curvatum. The specimen differs from the latter in that the epicyst is slightly less arciform. Reworked from Late Cretaceous (?Senonian) deposits. 214 Dimensions.- (1 specimen recovered): length 72.2m ; width 35.4m ; wall thickness 0.5m * Stratigraphic occurrence.- Section 3, very rare in sample 8476. Genus Eyrea Cookson and Eisenack, 1970b Eyrea nebulosa Cookson and Eisenack, 1971 Plate 16, Figure 14 Eyrea nebulosa Cookson and Eisenack, 1971, Proc. Roy. Soc. Victoria, vol. 84, p. 23, pi. 11, figs. 2-6. Comments.- Specimens agree well with illustrations of the type material. The lack of invaginations uniting the inner and outer walls was pointed out by Elsik (1977) as one feature distinguishing E. nebulosa from Para- lecaniella indenta (Deflandre and Cookson, 1955) Cookson and Eisenack 1970b emend. Elsik, 1977. The outer wall is generally poorly defined, almost nebulous, in the Seymour Island specimens. Dimensions.- Observed range (10 specimens): overall length 42-94p (70.6m mean); overall width 32-72m (65.9m mean); inner body length 32-72M (46.3m mean); inner body width 31-42m (37.7m mean). Stratigraphic occurrence.- Section 3, rare to abundant in all samples except 8445, 8451, 8453-8455, 8459, 8462, and 8468; Section 12-13, very rare in samples 8485 and 8492, rare in samples 8493 and 8494; Sec tion 15, sparse in sample 8496, rare in sample 8495, very rare in sample 8497; Section 16, rare in sample 8498; Section 17, rare in samples 8501 215 and 8502, very rare in sample 8500; Section 18, sparse in sample 8503, very rare in samples 8504 and 8505; Section 19, abundant in sample 8508, common in sample 8507, sparse in samples 8506 and 8512, rare in samples 8509 and 8511, very rare in sample 8510. Forma A Plate 6, Figures 10-16 Description.- SHAPE The ambitus varies from subellipsoidal to subtriangular. The ambitus is widest in the paracingular area on specimens of the former shape and antapically on those of the latter. Endophragm and periphragm are closely appressed except in the horns. The periphragm is drawn out into very long, slender apical and antapical horns. The base of the horns are often striate long itudinally. The endophragm generally does not extend into the horns and always forms a barrier preventing communication between the endocoel and the horns. This basal barrier is usually quite dark and may actually be a thickening of the endophragm. The horns are usually hollow and darker than the rest of the dino cyst. Some horns, however, are solid for three quarters of their length from the distal end. 216 PHRAGMA The periphragm is smooth, granular, rugulate, or reticulate. The more elaborate sculpture appears to be formed by low, discontinuous membranes. It is possible that some of the sculpture is an arti fact of preservation, because the periphragm is usually heavily folded. The endophragm is smooth. PARATABULATION An occasional paracingular fold and possible archeopyle parasutures suggest paratabulation. Indications are insufficient to determine even a partial paratabulation formulae. PARACINGULUM Some specimens bear a distinct fold or low ridges in the para cingular area. Such suggestions of a paracingulum are unspiraled. PARASULCUS Indications of a parasulcus are absent, except for an occasional shallow depression in the parasulcal area. 217 ARCHEOPYLE A distinct archeopyle was not observed on any of the hundred or so specimens examined. One or more parasutures(?) in the intercalary area were observed on many specimens. These suggest a 2a interca lary archeopyle is present. If this is the case, the operculum always remains attached and in place, apparently closing tightly after excystment. Discussion and comparison with similar dinocystBThe specimens are invariably broken and the horns seem to be particularly vulnerable to physical damage. Often the horns are sheared off at the base. Low resistance to chemical oxidation seems to be another characteristic of this species. The abundant, dark specimens observed in the source and maceral slides of sample 8470 were represented hardly at all in the final palynological slides. The examples present in the latter were invariably bleached out and corroded. This was true in spite of the minimal oxidative treatment used during sample preparation. The morpho logical variability of this species is quite pronounced, particularly with regards to the shape of the main body. Some specimens are similar to Imbatiodinium, but differ from that genus in having two wall layers and, most probably, an intercalary archeopyle. Forma A differs from Broomea by having two wall layers, the range of sculpturing and in the structure of the antapical horns. 218 Forma A differs from Pareodinia by nature of the former having two wall layers, two antapical horns and, probably, a Type I intercalary archeo pyle. Dimensions.- Observed range (10 specimens): endocyst length 44-57|J (mean 27.2p); pericyst width 21-39|J (mean 51.4p); apical horn length up to 54p; antapical horn length up to 36|J; periphragm thickness <0.5|J; endophragm thickness <0.5p. Stratigraphic occurrence.- Section 3, sparse in samples 8455 and 8477, rare in sample 8450, very rare in samples 8456, 8466, and 8470; Sec tion 19, very rare in sample 8512. Forma B Plate 11, Figures 7-10 Description.- SHAPE Subcircular chorate dinocyst bearing 40 or more hollow, nontabular processes. The process shafts may be subconical (tapering dis- tally), cylindrical or branched midway along their length. Two process shafts also may arise from a common base. The process terminations are closed distally and separate into two or more branches which may be bifurcate themselves. The more ela borate process terminations form 4 or 5 distal branches, each of which bifurcates into two subbranches whose tips often bifurcate or trifurcate yet again. 219 The base is broader than the rest of the process except for the distally flared, branching termination. The contact between the process base and the central body may be indicated by a ring. Some bases appear to be formed of 2 or more roots which join to form the shaft. PHRAGMA The endophragm is smooth to finely granular and usually covered by very fine wrinkles. The periphragm is smooth. Both wall layers <0.5|J thick. PARATABULATION None evident. PARACINGULUM None evident. PARASULCUS None evident. ARCHEOPYLE Ruptures have been observed in the central body suggesting an apical archeopyle. However, a distinct archeopyle has not been observed. 220 Dimensions.- Observed range (10 specimens): overall length 39-51|J (mean 44.3m ); overall width 23-40p (mean 32.8m ); endocyst length 29-48m (mean 37.3m ); endocyst width 20-41m (mean 27.5m ); process length 8-10m ; pro cess width 0.5-5m ; endophragm thickness <0.5m ; periphragm thickness <0.5m . Stratigraphic occurrence.- Section 3, abundant in sample 8457; Sec tion 17, common in all samples. Genus Hystrichosphaeridium Deflandre, 1937b, emend. Davey and Williams, 1966b Hystrichosphaeridium cf. astartes Sannemann, 1955 Plate 14, Figures 1-3 Hystrichosphaeridium astartes Sannemann, 1955, Senck. Leth., Vol. 36, nos. 5-6, p. 325, pi. 4, fig. 1. Comments.- Spherical central body covered with subconical, hollow protu berance, as in Hystrichosphaeridium astartes. The specimens compare well with the illustration of the type material, but are much smaller. The diameter of the H. astartes type specimen is 230m , whereas the Seymour Island specimens range from 42-50m - There are approximately 25 processes, whose bases abut against each other. H< astartes Sannemann 1955 was referred to as ?Baltisphaeridium astartes (Sannemann 1955) by Eisenack et al. (1973). Although astartes 221 undoubtedly does not belong in the genus Hystrichosphaeridium > a legiti mate transfer to another genus has never been effected. Dimensions.- (1 measurable specimen): central body diameter 31.9p; overall diameter 42.9p; process length approximately up to lOp; diameter of process bases up to lOp. Stratigraphic occurrence.- Section 3, rare in samples 8452, 8453, and 8478, very rare in samples 8462 and 8477. Hystrichosphaeridium parvum Davey, 1969b Plate 9, Figure 14 Hystrichosphaeridium parvum Davey, 1969b, Palaeontologies Africans, Vol. 12, p. 5, pi. 1, fig. 8, pi. 2, fig. 1. Comments.- The specimens compare favorably with the illustrations and description of type material from the Cretaceous of South Africa (Davey, 1969b). The endocyst, however, is distinctly granular. The processes, though smooth, have numerous longitudinal folds which look like ribbing at first glance. Dimensions.- Observed range (4 specimens): overall diameter 28-38|J (mean 32p); endocyst diameter 20-25|i (mean 22.9p); process length approximately 7.Op. Stratigraphic occurrence.- Section 3, rare in samples 8458 and 8478, very rare in samples 8443, 8447, 8465, 8468, 8470, 8472, 8474, 8475, and 222 8477; Section 16, very rare in sample 8499; Section 17, very rare in sample 8501; Section 18, very rare in samples 8503 and 8504; Section 19, very rare in samples 8506, 8507, 8511, and 8512. Hystrichosphaeridium salpingophorum Deflandre, 1935 emend. Davey and Williams, 1966b Plate 10, Figures 12, 13 Hystrichosphaeridium salpingophorum Deflandre, 1935, Bull. Biol. Fr. Belg., vol. 69, p. 232, pi. 9, fig. 1. Hystrichosphaeridium salpingophorum Deflandre, 1935, emend. Davey and Williams, 1969b, Bull. Br. Hus. Nat. Hist. (Geol.), Suppl. 3, p. 61-62, pi. 10, fig. 6. Comments.- Rare specimens agreeing closely with the emended diagnosis were encountered in Sections 15, 16, and 19. The paratabulation for mula, overall shape, number, and structure of the processes and the archeopyle type are the same as the material described by Davey and Wil liams (1966b). These authors also noted the presence, in some specimens, of a basal ring where the processes join the central body. The basal rings on the Seymour Island specimens are circular, subquadrate, or elliptical. Dimensions.- Observed range (5 specimens): Endocyst diameter 33-43|J (37p mean); process lengths to 27p. 223 Stratigraphic occurrence.- Section 15, very rare in sample 8495; Sec tion 16, very rare in sample 8499; Section 19, very rare in sample 8506. Hystrichosphaeridium tubiferum subsp. brevispinum (Davey and Williams, 1966b) Lentin and Williams, 1973 Plate 10, Figures 1-3 Hystrichosphaeridium tubiferum var. brevispinum Davey and Williams, 1966b, Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 58, pi. 10, fig. 10. Hystrichosphaeridium tubiferum subsp. brevispinum (Davey and Williams, 1966b) Lentin and Williams, 1973, Geol. Surv. Pap. Can., No. 73-42, p. 80. Comments.- The specimens differ from the illustrations of the type material in that the endophragm is granular whereas the periphragm is smooth. This is just the reverse of the type material (Davey and Wil liams, 1966b). In all other respects they are the same. Dimensions.- Observed range (2 specimens): endocyst diameter 39p (mean 39|j); process length 5-llp. Wall thickness: endophragm lp; periphragm <0.5p. Stratigraphic occurrence.- Section 3, very rare in sample 8465; Sec tion 15, very rare in sample 8495; Section 17, very rare in sample 8502; Section 18, very rare in samples 8503 and 8504. 224 Hystrichosphaeridium sp. A Plate 10, Figures 4-6, 10, 11 Description.- SHAPE A skholochorate dinocyst whose subspherical endocyst is formed by the finely granular endophragm. The operculum of the apical arche opyle often remains within the archeopyle opening. It was not pos sible to determine if this was entirely fortuitous or whether it is characteristically attached. PKRAGMA The smooth periphragm gives rise to infundibular intratabular pro cesses. The periphragm is closely appressed to the endophragm except beneath the process. Here the two wall layers separate, their divergence indicated by a faint ring at the base of most pro cesses. The endophragm is continuous beneath the processes, hence there is no communication between the endocoel and the hollow axis of each process. The distally flared process terminations are open and highly fenestrate. PARATABULATION Paratabulation is indicated only by the process distribution. The paratabulation formulae is 4', 6'', ?5c 6 '11, 1', ?3s. None of the specimens studied provided a clear assessment of the number of 225 paracingular and parasulcul processes. There may be more than is indicated here. The apical processes are distinctly shorter than all other processes. No preapical processes were observed. PARACINGULUM The location of the paracingulum is indicated by at least 5 intra tabula r pressures. The paracingulum is unspiraled. PARASULCUS Thin infundibular processes mark the location of the parasulcus. At least 3 parasulcal processes are present; however, the flexi bility of the processes and disadvantageous specimen orientations precluded precise determination of the total number present. ARCHEOPYLE The apical archeopyle is formed by the (?)partial or complete detachment of the apical series of paraplates. The operculum is a single piece because the apical paraplates do not separate from each other. Four paraplate centered infundibular processes arise from the surface of the operculum. Discussion and comparison with similar species.- The most similar species is H. tubiferum (Ehrenberg, 1838) Deflandre, 1937b. H. sp. A differs from H. tubiferum in that the periphragm is smooth and the endophragm is granular, rather than the reverse. The fenestrate process terminations of H. sp. A contrast markedly with 226 the "denticulate to serrate circular margins" (Davey and Williams, 1966b) of H. tubiferum. Finally, the processes of H. sp. A are more flexible that the typically stiff processes of H. tubiferum. The fact that the operculum is commonly present, perhaps being only partially detached, may prove to be important in distinguishing H. sp. A from H. tubiferum. However, more material must be studied before the validity of this speculation can be determined. Dimensions.- Observed range (5 specimens): diameter of endocyst 39-43p (mean 41.2|j); overall diameter 72-85|i (mean 78.7p); process length 7.5-15p); endophragm thickness <1.0|j; periphragm thickness <1.0|j. Stratigraphic occurrence.- Section 3, rare in sample 8465, very rare in samples 8457, 8458, 8463, 8470, and 8473; Section 17, rare in sample 8500, very rare in samples 8501 and 8502; Section 18, very rare in samples 8504 and 8505. Hystrichosphaeridium sp. Comments.- Specimens of Hystrichosphaeridium unassignable to a partic ular species due to poor preservation and acute folding were encountered in Section 19. Stratigraphic occurrence.- Section 19, very rare in samples 8510 and 8512. 227 Genus Impagidinium Stover and Evitt, 1978 Impagidinium dispertitum (Cookson and Eisenack, 196Sa) Stover and Evitt, 1978 L e ptodinium dispertitum Cookson and Eisenack, 1965a, Proc. Roy. Soc. Victoria, Vol. 79, p. 122-123, pi. 12, figs. 5-7. Impagidinium dispertitum (Cookson and Eisenack, 1965a) Stover and Evitt, 1978, Stanford University Publications Geological Sciences, Vol. 15, p. 165. Comments.- Rare specimens were observed which agree with the illustra tions and description of the type material described from the Upper Eocene Browns Creek Clay of Southwest Victoria, Australia. Differenti ation from I. maculatum and X* Victorianum was based upon contrasting size, sculpture and tabulation, as indicated by Cookson and Eisenack (1965a). Dimensions.- Observed range (3 specimens): diameter 56-65|J (mean 62.9p); wall thickness 2\i. Stratigraphic occurrence.- Section 3, very rare in sample 8462. 228 Impagidinium maculatum (Cookson and Eisenack, 1961b) Stover and Evitt, 1978 Plate 15, Figures 2, 3, 5, 6 Leptodiniuro maculatum Cookson and Eisenack, 1961b, J. Roy. Soc. W. Austral., Vol. 44, p. 40, pi. 2, figs. 5-6. Impagidinium maculatum (Cookson and Eisenack, 196lb) Stover and Evitt, 1978, Stanford University Publications, Geological Sciences, Vol. 15, p. 166. Comments.- Paratabular crests or ledges up to 4|J high. Granular endo cyst is approximately 3|i thick. Neither of these dimensions was noted in the original description. The specimens from Seymour Island agree with the illustrations and description of the type material. Most spe cimens were damaged and incomplete. Dimensions.- Observed range (2 specimens): Diameter 36-42|J (mean 38.8|j); crest height approximately 3|J. Stratigraphic occurrence.- Section 15, very rare in sample 8497; Sec tion 16, very rare in sample 8498; Section 19, very rare in samples 8506 and 8512. 229 Impagidinium victorianum (Cookson and Eisenack, 1965a) Stover and Evitt, 1978 Plate 15, Figures 8, 9, 11, 12 Leptodinium victorianum Cookson and Eisenack, 1965a, Proc. Roy. Soc. Victoria, Vol. 79, p. 123, pi. 12, figs. 8-9. Impagidinium victorianum (Cookson and Eisenack, 1965a) Stover and Evitt, 1978, Stanford University Publications, Geological Sciences, Vol. 15, p. 166. Comments.- Very rare, poorly preserved specimens were recovered from the Seymour Island material. Dimensions.- (1 specimen measurable): diameter 77|J; wall thickness approximately 3p. Stratigraphic occurrence.- Section 19, very rare in samples 8511 and 8512. Impagidinium sp. Comments.- Rare, poorly preserved and inadvantageously oriented speci mens were encountered in Section 3. Specific identification was impos sible because the parasulcal area was not observable. Stratigraphic occurrence.- Section 3, rare in sample 8462, very rare in sample 8465. 230 Impletosphaeridium sp. A. Plate 9, Figures 1-3 Description.- SHAPE Subrounded to ellipsoidal chorate dinocyst bearing numerous nonta- bular whip-like processes. The processes are solid, thin, and slightly tapered from the proximal to the distal ends. Process terminations may be bifid, trifid, or consist of a pad-like thick ening. The latter are usually angular and irregular in outline. Bifid terminations, often recurved, are most common. One or more termination types can occur on a single specimen. PHRAGMA The central body is finely granular, whereas the processes are smooth. It was not possible to determine if two wall layers are present. The difference in surface sculpture noted above suggests that there are two layers. PARATABULATION None evident. 231 PARACINGULUM None evident. PARASULCUS None evident. ARCHEOPYLE None evident. Discussion and comparison with other species of Impletosphaeridium.- The process termination of Impletosphaeridium sp. A. distinguishes it from all other species of this genus. This species occurs in all of the Seymour Island sections and is quite common in some samples. Dimensions.- Observed range (10 specimens): central body length 21-47p (mean 27.5m ) » central body width 18-37)J (mean 23.2p); length of pro cesses 8-12p; width of processes approximately 0.5fJ. Stratigraphic occurrence.- Section 3, very rare to abundant all samples except 8443-8446, 8450-8455, 8459, 8466, 8469-8471, 8477, and 8478; Sec tion 12-13, rare in samples 8490, 8492, and 8493; Section 15, rare in samples 8496 and 8497; Section 16, very rare in sample 8498; Section 17, rare in samples 8500 and 8502, very rare in sanqple 8501; Section 18, rare in sample 8503; Section 19, common in sample 8508, sparse in sample 8511, rare in sanq>le 8507, very rare in sample 8506. 232 Impletosphaeridium sp. B. Plate 12, Figures 4-8 Description.- SHAPE Skolochorate dinocysts bearing 30 or more nontabular processes. The proximally hollow processes are isolated from the endocoel by the endophragm. The distal half of each process is solid, closed, and terminated by a bifurcate, trifurcate, or multifurcate tip. The processes have a triangular cross-section with a rib or thick ening located at each apice and extending the entire length of the shaft. These lineations often continue out onto the surface of the central body, forming an irregular reticulation by joining those from adjacent processes. PHRAGMA The periphragm is smooth and often wrinkled. The endophragm is smooth to granular and usually wrinkled. PARATABULATION None evident. 233 PARACINGULUM None evident. PARASUICUS None evident. ARCHEOPYLE A distinct archeopyle has not been observed on any specimen. How ever, an angular opening in one specimen suggests that the archeo pyle is apical. Discussion and comparison with similar species.- The solid nature of the processes and the uncertainty as to the archeopyle type are the basis for assigning these specimens to the genus Impletosphaeridium. The dis tinctive structure of the processes and the irregular network on the surface of the endocyst distinguish I. sp. B. from all other Bpecies of Impletosphaeridium. DimensionsObserved range (2 measurable specimens): diameter 20-24|J (mean 22p); process length 7-10|j; periphragm thickness <0.5|j; endophragm thickness <0.5p. Stratigraphic occurrence.- Section 3, very rare in samples 8448, 8456, 8457, 8458, 8472, 8474, and 8479; Section 17, samples 8500 and 8501; Section 19, rare in sample 8511, very rare in samples 8507 and 8508. 234 Genus Impletosphaeridium Morgenroth, 1966a Impletosphaeridium sp. C. Plate 9, Figures 6, 7 Description.- SHAPE Autocyst: The central body is subrounded to elliptical. PHRAGHA Autophragm: Surface texture shagreenate to granular less than lp thick. PROCESS The nontabular processes are solid, whiplike and distally acumi nate. There are between 50 and 100 processes present. The pro cesses appear to be highly flexible. PARATABULATION There are no indications of paratabulation. PARACINGULUM None evident. 235 PARASULCUS None evident. ARCHEOPYLE None evident. Discussion and comparison with other species.- Although I. sp. C super ficially resembles Baltisphaerieium ligospinosum, the former is charac terized by whiplike acuminate processes. The processes of B. ligospi nosum, on the other hand, are quite stiff and their terminations are bifid or capitate as well as acuminate. Dimensions.- Observed range (4 specimens): length 21-33|J (mean 27p); width 21-25|J (mean 21.8|j); processes 10-15p; autophragm less than lp thick. Stratigraphic occurrence.- Section 3, very rare in samples 8449, 8457, 8464, and 8477; Section 12-13, very rare in sample 8492, rare in sample 8494; Section 15, rare in sample 8495, very rare in samples 8496 and 8497; Section 16, rare in sample 8498, very rare in sample 8499; Sec tion 17, very rare in sample 8501; Section 18, very rare in sample 8503; Section 19, rare in sample 8506. 236 Genus Isabelidinium Lentin and Williams 1977a Isabelidinium druggii (Stover, 1974) Lentin and Williams, 1977a Plate 1, Figure 12 Deflandrea druggii Stover, 1974, Spec. Pubis, geol. Soc. Aust., No. 4, p. 171, pi. 1, figs. 3 and 4. Isabelidinium druggii (Stover, 1974) Lentin and Williams, 1977a, Paly- nology, Vol. 1, p. 167. Comments.- Wilson (1978) compared Isabelidinium druggii with the closely related species I. seelandica and concluded they differ only in the latter possessing a pronounced apical horn. Both species were reported from the Late Maastrichtian-Danian of New Zeland (Wilson, 1978). Only 1* druggii has been observed in the Seymour Island material. Dimensions.- observed range (7 specimens); length pericyst 77-99|J (mean 89.7p); width pericyst 52-70jj (mean 59.8p); length endocyst 60-106p (mean 77.7fj); width endocyst 49-79p (mean 64.8p). Stratigraphic occurrence.- Section 3, sparse in sample 8451, very rare in samples 8457, 8464, 8472, and 8477. 237 Isabelidinium pellucjdum (Deflandre and Cookson, 1955) Lentin and Williams, 1977a Plate 1, Figures 13, 14 Peflandrea bakeri forma pellucida Deflandre and Cookson, 1955, Austral. J. Mar. Freshw. Res., Vol. 6, p. 251, pi. 4, fig. 3. Peflandrea pellucida (Deflandre and Cookson, 1955) Cookson and Eisenack, 1958, Proc. Roy. Soc. Victoria, Vol. 70, p. 27, pi. 4, fig. 9. Isabelidinium pellucidum (Deflandre and Cookson, 1955) Lentin and Wil liams, 1977a, Palynology, Vol. 1, p. 168. Comments.- The Seymour Island specimens agree closely with the original varital and specific descriptions, except with regards to surface sculp ture. Although the periphragm of some specimens is smooth or finely granular, like the type material, others are a coarsely granular or even rugalate surface. The paracingulum was indicated on one specimen by two rows of low grana. Dimensions.- Observed range (3 specimens): pericyst length 84-ll8|J (mean 105p); pericyst width 70-87|i (mean 78|j); endocyst length 54-72p (mean 60.6p); endocyst width 68-85p (mean 76p); wall thickness approxi mately lp. Stratigraphic occurrence.- Section 3, very rare in samples 8477 and 8478; Section 19, very rare in sample 8507. 238 Genus Kallosphaeridium De Coninck, 1969 Kallosphaeridium cf. capulatum Stover, 1977 Plate 7, Figures 11, 12 Kallosphaeridium capulatum Stover, 1977, A.A.S.P. Contrib. Series, No. 5A, p. 74, pi. 1, fig. 11-13. Comments.- Specimens comparable to Kallosphaeridium capulatum vary somewhat from the original material described by Stover (1977). Some of the Seymour Island specimens have a smaller overall diameter (30-33p vs. 46-50p) and a thicker autophragra (lp vs. 0.5p) than the type material. The granular sculpture is low and uniformly distributed. The apical archeopyle remains attached to the autocyst by a narrow tab. Accessory archeopyle sutures are generally present. Dimensions.- Observed range (5 specimens): length 29-36p (mean 32.6p); width 29-34p (mean 31.3p); wall thickness 2p. Stratigraphic occurrence.- Section 3, very rare in samples 8464, 8465, 8470, and 8472; Section 15, rare in sample 8495, very rare in sample 8496; Section 16, very rare in sample 8499. 239 Genus Lejeunecysta Artznec and Dorhofer 1978 emend. Bujak, 1980 Lejeunecysta fallax (Morgenroth, 1966b) Artzner and Dorhofer, 1978 Plate 5, Figure 3 le.jeunia fallax Morgenroth, 1966b, N. Jb. Geol. Palaont., Abh., Vol. 127, p. 2-3, pi. 1, fig. 6-7. lejeunecysta fallax (Morgenroth, 1966b) Artzner and Dorhofer, 1978, Canadian Jl. Bot., Vol. 56, p. 1381-1382. Comments.- Numerous specimens were recovered which differ from the description of the type material in that they are slightly less angular. The short apical and antapical horns are usually solid, subrounded to sharp and darker than the rest of the autocyst. The autophragm is smooth and without sculpture. The paracingulum, if present, is indi cated by parallel folds; parasulcus usually absent. When it is visible, the operculum of the standard hexa 2a archeopyle is usually attached along parasuture H4. The remaining archeopyle parasu- tures are clearly defined. Dimensions.- Observed range (10 specimens): length 48-92p (mean 69.7m ); width 60-81m (mean 66.5p); archeopyle dimensions (6 measurable): height 14-45M (mean 26.Op); width 22-50p (mean 31.Ip); wall less than lp thick. Stratigraphic occurrence.- Section 3, rare in samples 8456 and 8477. 240 Lejeunecysta hyalina (Gerlach, 1961) Artzner and Dorhofer, 1978 Plate 5, Figures 4, 6 Lejeunia hyalina Gerlach, 1961, N. Jb. Geol. Palaont., Abh., Vol. 112, p. 169, pi. 26, figs. 10-11. Lejeunecysta hyalina (Gerlach, 1961) Artzner and Dorhofer, 1978, Cana dian Jl. Bot., Vol. 56, p. 1381. Comments.- The Seymour Island specimens are identical to the description and illustrations of the type material, except their overall dimensions vary through a broader range. The autophragm is relatively flexible and transparent, but appears dark wherever it is folded over upon itself. The short apical and antapical horns are solid and generally sharp dis- tally. The operculum is usually attached posteriorly along the H4 para- suture of the standard 2a archeopyle. Dimensions.- Observed range (7 specimens): length 59-121|i (mean 91.9|j); width 47-105|J (mean 84.2p); archeopyle dimensions (1 measurable): height 34|J; width 40. l\x. Stratigraphic occurrence.- Section 3, rare in samples 8456 and 8477; Section 15, very rare in sample 8497. 241 lejeunecysta sp. Comments.- Specimens of Lejeunecysta too highly folded or degraded to assign to a species are assigned only to generic level. Stratigraphic occurrence.- Section 3, very rare in samples 8456, 8464, 8465, and 8470; Section 15, very rare in sample 8495; Section 17, very rare in samples 8500 and 8501. Genus Odontochitina Deflandre, 1935 emend. Davey, 1970 Odontochitina cf. operculata (0. Wetzel, 1933a) Deflandre and Cookson, 1955 Plate 14, Figures 10, 11 Ceratium operculatum 0. Wetzel, 1933, Palaeontog., Abt. A, Vol. 77, p. 170, pi. 2, figs. 21-22, text-fig. 3. Odontochitina operculata Deflandre and Cookson, 1955, Austral. J. Mar. Freshw. Res., Vol. 6, p. 291-292, pi. 3, figs. 5 and 6. Comments.- Rare specimens encountered in the La Meseta Formation differ from description of the the type material in only one significant respect. The periphragm is sparsely covered with short, solid spines with acuminate to bifid distal terminations. They are generally nonta- bular, though the paracingulum was clearly defined on one specimen by two parallel rows of spines. The spines are longest and most densely concentrated adjacent to the central body. Sculpture on the antapical horns is limited to short spines and scattered grana. 242 Reworked from the Cretaceous (Hauterivian-Carapanian) deposits. Dimensions.- (1 undamaged specimen): length overall 149.6p; width overall 90.9p; endocyst length 81p; endocyst width 90.2p; periphragm thickness less than lp; endophragm approximately 2|J thick; spine length 1.0-6.6p. Stratigraphic occurrence.- Section 3, very rare in sample 8476. Genus Oligosphaeridium Davey and Williams, 1966b Oligosphaeridium complex (White, 1842) Davey and Williams, 1966b Plate 12, Figures 11, 12 Xanthidium tubiferum complex White, 1842, MicroBCOpial Journal, London, V o l . 11, p . 39, p i . 4, d i v . 3, f i g . 11. Oligosphaeridium complex (White, 1842) Davey and Williams, 1966b, Bull. Br. Mus. Nat. Hist. Geol., Supp. 3, p. 71-74. Comments.- Rare, highly distorted specimens attributable to Oligosphaer idium complex were recovered from the La Meseta Formation samples. The specimens are usually broken; however, the absence of paracingular pro cesses and the presence of distinctive secate and aculeate process ter minations facilitate identification. Basal rings mark the contact of the hollow processes and the central body. Periphragm slightly gran ular. Archeopyle apical. 243 Dimensions(1 measurable specimen): central body length 50.6|j; cen tral body width 40.7m ; process length up to 27p. Stratigraphic occurrence.- Section 3, rare in sample 8451, very rare in samples 8443, 8457, and 8476; Section 17, very rare in sample 8502; Sec tion 19, very rare in sample 8508. Oligosphaeridium pulcherrimum (Deflandre and Cookson, 1955) Davey and Williams, 1966b Plate 9, Figures 15, 16 Hystrichosphaeridium pulcherrimum Deflandre and Cookson, 1955, Austral. J. Mar. Freshw. Res., Vol. 6, p. 270, pi. 1, fig. 8. Oligosphaeridium pulcherrimum (Deflandre and Cookson, 1955) Davey and Williams, 1966b, Bull. Br. Hus. Nat. Hist. (Geol.), Suppl. 3, p. 75-76. Comments.- Very rare specimens of Oligosphaeridium bearing the distinc tive hollow and distally fenestrate processes are assigned to 0. pulcherrimum. Periphragm is smooth to shagreenate; however, since the specimens are poorly preserved, any surface sculpture may have been removed. Reworked from Late Jurassic-Late Cretaceous (Portlandian to Campanian, respectively) deposits. Dimension.- Observed range (2 measurable specimens recovered): central body length 54-63M (mean 58.5m ); central body width 44-52p (mean 48m ); 244 wall thickness approximately l|j; process length 28-42|J; process width 3—7p; process terminations up to 38p across. Stratigraphic occurrence.- Section 3, very rare in samples 8451, 8457, and 8476. Oligosphaeridium sp. Comments.- Specimens assignable to Oligosphaeridium but unassignable to a species, because of poor preservation, were grouped under this heading. Stratigraphic occurrence.- Section 3, very rare in samples 8457, 8458 and 8465; Section 15, very rare in sample 8495. Genus Operculodinium Wall, 1967 Operculodinium bergmannii (Archangelsky, 1969a) Stover and Evitt, 1978 Plate 10, Figures 7-9; Plate 14, Figures 5-7 Cleistosphaeridium bergmannii Archangelsky, 1969a, Ameghiniana, vol. 5, p. 414-415, pi. 1, figs. 8 and 11. Operculodinium bergmannii (Archangelsky, 1969a) Stover and Evitt, 1978, Stanford Univ. Pubs., Geological Sciences, No. 5A, p. 178. Comments.- The dinocyst wall is thick (2 to 5p) and spongy in cross- section. Some specimens exhibit a granulate surface, as reported by Archangelsky (1969a). Most specimens, however, have a microfoveolate 245 surface which runs up onto the process bases. This results in highly perforated process bases or, put another way, processes which appear to form from a number of root-like strands of wall material. Processes are short (<10|j), solid, and may be highly variable in shape, even on one specimen. They may consist of a single shaft or be formed by the joining of two or more shafts. Two or more processes may arise from a single broad base. Process terminations may be capitate, acumi nate, bifid, or bifurcate. The archeopyle is precingular (3P). No other indication of tabulation was observed. Dimensions.- Observed range (10 specimens): endocyst diameter 37-65|J (48.2|J mean); process length 7-15p (8.8|J mean); wall thickness 1-4|J (mean 2.6p). Stratigraphic occurrence.- Section 3, rare in samples 8456, 8458, and 8461, very rare in samples 8447, 8457, 8460, 8462, 8465, 8467, 8468, 8470, 8472, 8475, and 8478; Section 15, rare in sample 8497, very rare in sample 8495; Section 16, rare in sample 8499; Section 19, rare in samples 8511 and 8512. 246 Genus Palaeocystodinium Alberti, 1961 Palaeocystodinium australinum (Cookson, 1965 emend. Malloy, 1972) Lentin and Williams, 1976 Plate 6, Figures 4, 5, 7 Svalbardella australinum Cookson, 1965, Proc. Roy. Soc. Victoria, vol. 78, p. 140, pi. 25. Palaeocystodinium australinum (Cookson 1965 emend. Malloy, 1972) Lentin and Williams, 1976, Bedford Inst. Oceanography Rept. BI-R-75-16, p. 89. Comments.- The Seymour Island specimens of Palaeocystodinium australinum resemble those from the Pebble Point Formation (Cookson 1965). However, they are generally somewhat shorter and darker than the West Australian specimens. The darker coloration is believed to be a preservational artifact because other taxa in the same samples are similarly colored. Many of the Seymour Island specimens of P. australinum often are broken just anteriorly of the paracingular area. Such specimens can only be differentiated from broken specimens of P. golzowense by the presence of 4 the accessory spur on the antapical horn of the former. The archeopyle is intercalary (2a) and the operculum is usually in place even though it is completely surrounded by parasutures. Dimensions.- Observed range (10 specimens): pericyst length 170-226(1 (mean 196.8(0; pericyst width 29-48(1 (mean 38.4(i); endocyst length 77-122(1 (mean 99.3(1); endocyst width 29-48(1 (mean 38.1(i). 247 Stratigraphic occurrence.- Section 15, very rare in sample 8497; Section 16, very rare in sample 8498. Palaeocystodinium golzowense Alberti, 1961 Plate 6, Figure 8 Palaeocystodinium golzowense Alberti, 1961, Palaeontographica, Abt. A, vol. 116, p. 20, pi. 7, figs. 10-12, pi. 12, fig. 16. Comments.- The Seymour island specimens are identical to those described by Alberti (1961) from the Golzow borehole except that the former are generally smaller. Endophragm and periphragm smooth and without any morphological expression of tabulation, paracingulum or parasulcus. Intercalary archeopyle (2a) with operculum usually in place though com pletely surrounded by parasutures. Dimensions.- Observed range (10 specimens): pericyst length 155-289|J (mean 194.85|j); pericyst width 27-43p (mean 37.6p); endocyst length 52-lll|j (mean 93.2|j); endocyst width 27-42p (mean 37.2p). Stratigraphic occurrence.- Section 3, very rare in sample 8457; Sec tion 12-13, rare in sample 8490, very rare in sample 8492; Section 15, rare in sample 8495, very rare in sample 8497; Section 16, very rare in samples 8498 and 8499. 248 Palaeocystodinium granulatum (Wilson, 1967b) lentin and Williams, 1976 Plate 6, Figures 3, 9 Svalbardella granulatum Wilson, 1967b, N.Z. Jl. Bot., Vol. 5, p. 226-227, figs. 7-9. Palaeocystodinium granulatum (Wilson, 1967b) lentin and Williams, 1976, Bedford Instit. Oceanog. Rept. BI-R-75-16, p. 89. Comments.- The Seymour Island specimens are very similar to the illus trations and description of the type material, except for surface sculp ture. Wilson (1967b) states the most characteristic feature of Palaeo cystodinium granulatum is "the densely granulated surface of the outer cyst". The specimens studied are more spinate than granulate, being covered with short evexate, bifid or bifurcate spines. Some spines are connected distally. Spine length varies between specimens as well as on an individual. The spines are generally shorter on the horns, being longer near the body of the cyst. Low grana are scattered between the spines and seemed to be more prominent on the horns. Whether or not the presence of short spines, as well as grana, is suffi cient reason to establish a new species cannot be determined based upon the few damaged specimens recovered. For the present, the Seymour Island material is considered to be a morphological variant of P. granulatum. 249 Reworked from late Cretaceous (Late Campanian-Maastrichtian) deposits. Wilson (1967b) originally described P. granulatum from the Garden Cove Formation, Campbell Island and assigned a Paleocene (Xeurian) age to the microflora. The age assigned to the formation was subsequently changed to Late Cretaceous (Wilson, 1972). Dimensions.- No complete specimens were observed. However, the peri phragm of one specimen broken in half was 127p long and 42(J wide. An approximate overall length of 260p does not seem unreasonable. These dimensions compare favorably with the range reported for P. granulata (Wilson, 1967b). Stratigraphic occurrence.- Section 3, very rare in samples 8457 and 8460. Palaeocystodinium sp. Comments.- A number of incomplete smooth bodied specimens of Palaeocys todinium were encountered. These were anterior halves, which are iden tical in P. golzowense and P. australinum. Specific identification was not possible because the distinctive antapical horns were broken off. Stratigraphic occurrence.- Section 3, rare in sample 8479; Section 16, rare in sample 8498. 250 Geous Palaeoperidinium Deflandre, 1935, emend. Sarjeant 1967b Palaeoperidinium pyrophorum (Ehrenberg, 1838) Sarjeant, 1967b Plate 5, Figures 7, 8 Peridinium pyrophorum Ehrenberg, 1838, pi. 1, figs. 1, 4. Palaeoperidinium pyrophorum (Ehrenberg, 1838) Sarjeant, 1967b, Grana Palynologica, Vol. 7, p. 246-247. Comments.- Some of the Seymour Island specimens exhibit a distinct folding or thickening along the anterior margins of paraplate 2a and a distinctly "contracted" endocyst. Otherwise the specimens closely resemble the emended species diagnosis (Sarjeant, 1967b). Dimensions.- Observed range (10 specimens): length 88-124|J (mean 104.3p); width 85-99JJ (mean 90.9m )« Stratigraphic occurrence.- Section 3, common in sample 8464, sparse in sample 8461, rare in sample 8461, very rare in samples 8443, 8456-8458, 8461, 8463, 8464, 8476, and 8478; Section 12-13, rare in samples 8490 and 8493; Section 15, abundant in samples 8495 and 8496, common in sample 8497; Section 16, abundant in sample 8498; Section 18, rare in sample 8505; Section 19, very rare in samples 8506 and 8508. 251 Genus Paralecaniella Cookson and Eisenack, 1970b emend. Elsik, 1977 Paralecaniella indentata (Deflandre and Cookson, 1955) Cookson and Eisenack, 1970b, emend. Elsik, 1977 Plate 14, Figure 9 Epicephalopyxis indentata Deflandre and Cookson, 1955, Aust. Jl. Mar. Freshwater Res., Vol. , p. 292, pi. 9, figs. 5-7. Paralecaniella indentata (Deflandre and Cookson, 1955) Cookson and Eise nack, 1970b, emend. Elsik, 1977, Palynology, Vol. 1, p. 96, pi. 1, figs. 1-15, pi. 2, fig. 1-11. Comments.- Elsik's (1977) definitive paper on Paralecaniella indentata describes and clearly illustrates the wide range of morphologic vari ability to be expected within this taxon. The Seymour Island material was equally variable, but exhibited one feature, possibly preservational in nature, not noted by Elsik (1977). Broken specimens often appeared to have been fractured or shattered, suggesting their walls were very stiff, if not brittle, in nature. Other specimens, however, did not convey such an impression. No indications of an archeopyle or a para- sulcus were observed. A number of specimens did exhibit a distinct paracingulum. Dimensions.- Observed range (10 specimens): pericyst length 36-80p (mean 52.6|j); pericyst width 35-68|J (mean 47.8p); endocyst length 32-77p (mean 47.3p); endocyst width 31-62M (mean 40.7|i)* 252 Stratigraphic occurrence.- Section 3, very rare in all samples except 8445, 8451-8455, and 8459; Section 12-13, abundant in samples 8492-8494, sparse in sample 8490, very rare in samples 8483 and 8488; Section 15, rare in all samples; Section 16, rare in sample 8499, very rare in sample 8498; Section 17, very rare in samples 8501 and 8502; Section 18, abundant in samples 8503 and 8505, rare in sample 8504; Section 19, common in sample 8510, sparse in sample 8509, rare in samples 8507, 8508, and 8511, very rare in samples 8506 and 8512. Genus Pareodinia Deflandre 1947 emend. Stover and Evitt, 1978 Pareodinia sp. Plate 6, Figure 6 Comments.- One poorly preserved specimen attributable to Parodinia was recovered. The apical horn has been broken off and there is no indica tion of paratabulation. The archeopyle appears to be intercalary. Reworked from Middle Jurassic-Early Cretaceous (Bajocian to Albian) deposits. Dimensions.- (1 specimen recovered): length 63.9p; width 29.Ip. Stratigraphic occurrence.- Section 19, very rare in sample 8509. 253 Geaus Phelodinium Stover and Evitt, 1978 Phelodiniuro sp. A. Plate 5, Figures 1, 2 Description.- SHAPE Pericyst: Squat peridinioid dinocysts whose breadth generally exceeds their length. The antapical horns are approximately the same length. The short apical horn is usually flat or slightly concave distally. The two epicystal sides are slightly longer than the three sides of the hypocyst. Endocyst: The endocyst mimics the shape of the pericyst, the two walls being closely appressed except near the horns and para- cingulum. PHRAGMA Periphragm: The periphragm is smooth, scabbrate or rugulate. Less than 0.5M thick. Endophragm: Smooth to finely granulate. Less than 0.5m thick. PARATABULATION There is no indication of paratabulation in either the pericyst or endocyst. 254 PARACINGULUM The paracinguluin is narrow, planar and bordered by low folds in the periphragm. The location of the paracingulum is indicated by a short truncated projection on each side of the ambitus. PARASULCUS Suggested by two low converging folds on the hypocyst. Broadest posteriorly. Not always evident. ARCHEOPYLE No distinct archeopyle has been observed, though occasional sutures in the epicyst suggested an intercalary archeopyle (?2a). Discussion and comparison with similar species.- Phelodinium sp. A. is closest to P. pumilum in that the antapical horns of both are rather short. P. sp. A. differs from the latter in being much larger, gener ally broader than long, and lacking a distinct archeopyle. The angular to subangular ambitus and surface sculpture are also distinctive in P. sp. A. Dimensions.- Observed range (10 specimens): length 63-130fJ (mean 87.7m ); width 60.5-129p (mean 87.7m ); periphragm and endophragm each less than 0.5M thick. Stratigraphic occurrence.- Section 3, rare in samples 8450 and 8478, very rare in samples 8457, 8458, 8464, 8465, 8467, 8470, 8473, 8475, 255 8476, and 8479; Section 15, rare in sample 8495; Section 17, very rare in sample 8500; Section 18, rare in sample 8505, very rare in sample 8503; Section 19, rare in sample 8508, very rare in samples 8511 and 8512. Genus Phthanoperidinium Drugg and Loeblicb, 1967 Phthanoperidinium echinatum Eaton, 1976 Plate 2, Figures 1-4 Phthanoperidinium echinatum Eaton, 1976, Bull. Br. Hus. Nat. His. (Geol.), Vol. 26, p. 298-299, pi. 17, figs. 8-9, 12; text-fig. 23B. Comments.- The Seymour Island specimens closely resemble those from the Brecklesham Beds of England (Eaton, 1976). The rounded polygonal out line and blunt apical horn are the same as noted by Eaton (1976); how ever, antapical projections also have been observed on some of the Seymour Island specimens. The left antapical horn is always the most prominently developed if antapical horns are indeed present. The posi tion of the nascent right antapical horn is usually indicated only by a tuft of solid spines capped distally by a ball or spherical termination. The distinctive, spinate, penitabular ornamentation clearly delineates a paratabulation of 4', 3a, 7,r, 5 ,f', 211" on the surface of the dino cyst. The paratabular areas thus formed assist in the identification of P. echinatum even in highly folded and distorted specimens. The archeopyle is formed by the loss of the 2a paraplate. Combination archeopyles, characteristic of ?Phthanoperidinium pseudoechinatum, were not observed in any specimens of the study material. 256 The Seymour Island specimens were generally much larger (34.1 x 59.4jj to 49.5 x 59.4|J) than Eaton's (1976) specimens (22 x 26|J to 42 x 48p). The spine lengths of both assemblages were 2|J or less. Dimensions.- Observed range (10 specimens); length 43-59p (mean 48.5fi); width 34~50|J (mean 4 3 .1 |j); spine length <2p. Stratigraphic occurrence.- Section 3, rare in samples 8461, 8465, 8468, 8477, and 8478, very rare in samples 8443, 8447, 8464, 8470, 8473, 8474, and 8476; Section 12-13, very rare in samples 8482, 8488, 8490, and 8492-8494; Section 17, rare in sample 8502, very rare in samples 8500 and 8502; Section 19, abundant in sample 8512, common in sample 8511, very rare in samples 8506 and 8507. Genus Selenopemphix Benedek, 1972 emend. Bujak, 1980 Selenopemphix nephroides Benedek, 1972 emend Bujak, 1980 Plate 5, Figure 5 Selenopemphix nephroides Benedek, 1972, Palaeontographica, Abt. B., Vol. 137, p. 47-48, pi. 11, fig. 13; pi. 16, fig. 1-4. Selenopemphix nephroides Benedek, 1972 emend. Bujak, 1980, Palaeont. Assoc., Spec. Papers Palaeont., No. 24, p. 84. Comments.- The Seymour Island specimens are identical to the description and illustration of the type material from the lower Rhine area of Ger many described by Benedek (1972). 257 Dimensions.- Observed range (10 specimens): height 42-68p (mean 52.2p); width 46-66p (mean 58.9p); archeopyle dimension (6 specimens): height l4-24p (mean 19.9p); width 14-29|J (mean 24p); wall less than lp thick. Stratigraphic occurrence.- Section 3, sparse in samples 8456 and 8477. Genus Senegalinium Jain and Millepied, 1973, emend. Stover and Evitt, 1978 Senegalinium asymmetricum (Wilson, 1967a) Stover and Evitt, 1978 Plate 1, Figures 4, 8, 9 Deflandrea asymmetrica Wilson, 1967a, N.Z. Jl. Bot., Vol. 5, No. 1, p. 62-63, figs. 17-21. Senegalinium ?asymmetricum (Wilson, 1967a) Stover and Evitt, 1978, Stan ford Univ. Pubs., Geological Sciences, Vol. 15, p. 123. Comments.- The specimens studied compare closely with the McMurdo Sound specimens (Wilson, 1967a) in regards to the shape, size, archeopyle type (2a), size and asymmetric development of the antapical horns and the intermittant occurrence of fine marginal serrations. The Seymour Island specimens differ most significantly from the type specimens in the granular, rather than smooth, surface of the endocyst. Although this is a consistent feature in the study specimens, it does not seem to be a significant enough difference upon which to establish a new species. 258 Dimensions.- Observed range (10 specimens): pericyst length 62-92|J (mean 81.6p); pericyst width 56-85p (mean 67.7p); endocyst length 40-6l|J (mean 46.7p); endocyst width 51-70p (mean 57.7p). Stratigraphic occurrence.- Section 3, rare in sample 8464; Section 18, rare in samples 8504 and 8505; Section 19, rare in samples 8511 and 8512; very rare in sample 8506. Genus Spinidinium Cookson and Eisenack, 1962b emend. Lentin and Williams, 1976 Spinidinium densispinaturo Stanley, 1965 Plate 5, Figure 12 Spinidinium densispinaturn Stanley, 1965, Bull. Amer. Palaeo., Vol. 49, p. 226-227, pi. 21, fig. 1-5. Comments.- Subpentagonal to almost oval ambitus with short, broad apical and antapical horns. The left antapical horn is always more developed than the right antapical horn, which often appears to be vestigial. Parasulcal area devoid of the notabular spines which densely cover the remainder of the dinocyst. Paracingulum bordered by rows of spines. Spines may be cylindrical, acuminate or capitate. Archeopyle not clearly seen on any specimen, but is assumed to be formed by the loss of the 2a paraplate. The specimens studied compare closely with the description and illustra tions of the type material from the Cannonball Member of the Fort Union formation (Stanley, 1965). 259 Dimensions.- Observed range (10 specimens): overall length 36-52p (mean 45.1|J); overall width 31-46p (mean 37.5m ). Stratigraphic occurrence■- Section 3, rare in samples 8452 and 8464, very rare in sample 8457; Section 12-13, abundant in sample 8490, common in samples 8493 and 8494, rare in sample 8492, very rare in samples 8483 and 8486; Section 15, sparse in sample 8497, rare in sample 8495, very rare in sample 8496; Section 16, very rare in sample 8499; Section 19, rare in sample 8512. Spinidinium essoi Cookson and Eisenack, 1967a Plate 5, Figure 14 Spinidinium essoi Cookson and Eisenack, 1967a, Pro. Royal. Soc. Vic toria, V. 80, p. 135, pi. 19, figs. 1-8. Comments.- The apical horn is concave distally and usually bears 2 or more small, solid capitate spines on its very end. Paratabulation is suggested by the linear distribution of spines. Penetabular capitate spines outline the anterior end and the two sides of the posteriorly attached 2a operculum. The left antapical horn terminates in a sharp point which may bear one or more capitate spines distally. The location of*£he right antapical horn is usually only suggested by a slight posterior bulge and/or a clump of short, capitate spines. 260 The Seymour Island specimens compare quite closely with the description of the Vestern Tasmanian material (Cookson and Eisenack, 1967a). Dimensions.- Observed range (10 specimens): overall length 49-70|J (mean 59.8|J); overall width 34-54|J (mean 46.Ip). Stratigraphic occurrence.- Section 3, common in sample 8462, sparse in samples 8463 and 8468, rare in samples 8443, 8447, 8461, 8469, 8471, 8472, 8473, 8474, and 8475, very rare in samples 8457, 8460, 8464, 8465, 8467, 8470, 8476, and 8479; Section 12-13, sparse in sample 8494, very rare in sample 8494; Section 17, sparse in samples 8501 and 8502; Sec tion 18, rare in samples 8503 and 8504; Section 19, rare in samples 8506, 8507, 8511, and 8512, very rare in sample 8508. Spinidinium lanternuro Cookson and Eisenack, 1970a Plate 5, Figures 15, 16 Spinidinium lanternum Cookson and Eisenack, 1970a, Proc. Roy. Soc. Vic toria, Vol. 83, p. 144-145, pi. 12, figs. 1-3. Comments.- As noted by Cookson and Eisenack (1970a),- paratabulation is most evident on the epicyst. Parasutural, solid spines delineate the 2a and 6 precingular paraplates. The parasulcal and paracingular areas are undivided internally and are devoid of the small solid spines which del imit their boundaries. The parasutural spines are solid and may be truncated, broadly acumi nate, capitate or bifid distally. 261 The broad apical horn is concave distally and usually bears 2 or more capitate spines on each side of the depression. The left antapical horn is always more developed than that on the right. The former may be a very stout, sharp, spine convered spike. The endocyst is often more globular and less appressed to the pericyst than is indicated for the type material (Cookson and Eisenack, 1970a; see their Plate 12, figs. 1-3). Dimensions.- Observed range (10 specimens): pericyst length 53-66p (mean 61.l|j); pericyst width 32-46p (mean 69.3p); endocyst length 20-36p (mean 32.9p); endocyst width 27-43p (mean 34.3p); archeopyle height 8-26p (mean 17.2p); archeopyle width 9-14p (mean 11.6p). Stratigraphic occurrence.- Section 3, rare in sample 8451, very rare in samples 8457 and 8458; Section 16, abundant in sample 8499. Spinidinium macmurdoense (Wilson 1967a) Lentin and Williams 1976 Plate 5, Figure 13 Deflandrea macmurdoense Wilson, 1967a, N.Z. Jl. Bot., Vol. 5, No. 1, p. 60, figs. 2a, 11-16, 22. Spinidinium macmurodense (Wilson 1967a) Lentin and Williams, 1976, Bed ford Inst. Oceanography Kept. BI-R-75-16, p. 64. 262 Comments.- The Seymour Island specimens compare closely with those described by Wilson (1967a), except that the operculum is not always outlined by small spines. The same extreme variation in ambital outline indicated in the McHurdo Sound specimens (Wilson, 1967a; Figures 11-16) was observed in the Seymour Island material. Dimensions.- Observed range (10 specimens): pericyst length 69-94p (mean 85.Op); pericyst width 53-107p (mean 66.4p); endocyst length 46-6lp (mean 54.8p); endocyst width 48-61p (mean 54.5p); archeopyle height 15-24p (mean 19.Op); archeopyle width 17-24p (mean 19.7p). Stratigraphic occurrence.- Section 3, sparse in samples 8458, 8465, and 8475, rare in samples 8447, 8464, 8467-8469, and 8472, very rare in sam ples 8443, 8457, 8460, 8463, 8470, 8473, 8474, and 8479; Section 17, rare in sample 8500; Section 18, abundant in sample 8504, sparse in sample 8503, rare in sample 8505; Section 19, sparse in sample 8506, very rare in sample 8509. Spinidinium sp. A. Plate 5, Figures 9-11 Description.- SHAPE Cornucavate, subpentagonal to subelliptical dinocysts bearing one hundred or more penetabular spines. A slightly laevorotatory para- cingulum separates the epicyst from the hypocyst; the former is usually two to three times the length of the hypocyst. 263 The short apical horn is capped by two or more capitate spines. The right antapical horn is rarely evident, whereas the left horn is usually a long spike shaped projection bearing one or more accessory spines. The paracingular area may bulge laterally, giving the dinocyst a subpentagonal shape. PHRAGMA Both the endophragm and the periphragm are smooth. The wall layers are closely appressed except in the basal regions of the horns. The periphragm gives rise to the many capitate spines, whereas the endophragm completely lacks projections. PARATABULATION Paratabulation is delineated by penetabular capitate spines. The precise distribution and number of paraplates is obscured by the abundance of closely spaced spines, which are often folded over each other. In addition, determining the tabulation is complicated the presence of by accessory rows of spines (i.e., spine rows interpreted as not being penetabularly arranged). Consequently, the paratabulation formula given below is considered tentative. Scanning electron microscopic examination may facili tate determining the precise tabulation. 264 The observed paraplate boundaries suggest a paratabulation formula of: ?', 3a, 7*', Xc, 5 1 * *, 72'', Os. The paracingulum and the parasulcus are not divided by rows of spines. The only paraplate clearly defined is the operculum of the hexa 2a archeopyle. PARACINGULUM Low folds capped with short capitate spines clearly delimit the paracingulum. Paraplate divisions within the paracingulum were not observed. The lateral margins may be slightly indented, indicating the paracingulum can also be expressed as a groove. PARASULCUS A broad, bare area bordered by rows of spines indicates the loca tion of the parasulcus. Spines are usually absent within the para- sulcal area, though isolated spines occur in some specimens. ARCHEOPYLE The archeopyle is formed by the partial detachment of the 2a para plate. The operculum characteristically remains attached along the H4 parasuture. A row of penetabular capitate spines occurs adja cent to both sides of parasutures H1-H3 and H5-H6. Both rows of spines continue below the archeopyle base to the anterior margin of the paracingulum. No indications of the H4 parasuture were observed on any specimens. 265 Discussion and comparison with similar species.- The capitate spines and their distribution on the pericyst are reminiscent of Spinidinium mac murdoense. However, the overall shape, more numerous spines, more com plete paratabulation and the unequal division of the dinocyst by the paracingulum differentiate S. sp. A. from S. macmurdoense. The dense spinosity of the pericyst of S. sp. A. is similar to a specimen of Voz- zhennikovia apertura illustrated by Haskell and Wilson (1975; plate 1, figure 6). However, the spines on the latter are nontabular, rather than penetabular. Dimensions.- Observed range (10 specimens): pericyst length 42-57p (mean 49. 9jj) ; pericyst width 36-45|J (mean 40.6|j); endocyst length 32-40p (mean 37.Ip); endocyst width 30-4lp (mean 34p); process length 3-8p; left antapical horn to lOp; apical horn to 8p. Stratigraphic occurrence.- Section 3, rare in samples 8457 and 8464, very rare in sample 8479; Section 12-13, abundant in sample 8483; Sec tion 15, common in all samples; Section 16, sparse in sample 8498. Spinidinium sp. Comments.- Specimens of Spinidinium unassignable to a species due to poor preservation are grouped under Spinidinium sp. Stratigraphic occurrence.- Section 3, sparse in samples 8463 and 8464, rare in samples 8449, 8450, 8457, 8462, 8466, 8467, and 8475, very rare in samples 8447, 8448, 8458, 8465, 8468, and 8469; Section 12-13, very rare in sample 8480; Section 16, very rare in sample 8499; Section 17, 266 rare in sample 8500; Section 18, very rare in sample 8503; Section 19, very rare in samples 8511 and 8512. Genus Spiniferites Mantell, 1850 emend. Sarjeant, 1970 Spiniferites cf. cornutus (Gerlach, 1961) Sarjeant, 1970 Plate 11, Figure 4 Hystrichosphaera cornuta Gerlach, 1961, Neues Jahrb. Geol. Palaontol., Abh., Vol. 112, p. 180, pi. 27, figs. 10-12. Spiniferites cornutus (Gerlach, 1961) Sarjeant, 1970, Grana, Vol. 10, p. 76. Comments.- One specimen was recovered. It compares closely with the description of the type material. The long apical process, however, is somewhat ventrally located, rather than arising from the absolute apex of the dinocyst. Dimensions.- (1 specimen): pericyst length 47|J; pericyst width 32p; endocyst length 45.Ip; endocyst width 31.9p; length of processes 5-l6|J. Stratigraphic occurrence.- Sections 12-13, very rare in sample 8490. 267 Spiniferites ramosus (Ehrenberg, 1838) Loeblich and Loeblich, 1966 Plate 12, Figures 13-15 Xanthidium ramosus Ehrenberg, 1838, Abh. preuss. Akad. Wiss., 1836, pi. 1, figs. 1, 2, 5. Spiniferites ramosus (Ehrenberg, 1838) loeblich and Loeblich, 1966, Stud. Trop. Oceanogr. Miami, No. 3, p. 56-57. Comments.- Specimens referable to this species are rare in the Seymour Island material. The processes are usually rather thin, as are the endophragm and the periphragm. Dimensions.- Observed range (2 specimens): endocyst length 35-4l|j; endocyst width 29—36|J; length of processes up to 14(J. Stratigraphic occurrence.- Section 3, very rare in samples 8465, 8468, and 8472; Section 16, very rare in sample 8499; Section 17, very rare in sample 8501. Spiniferites ramosus subsp. granomembranaceus (Davey and Williams, 1966a) Lentin and Williams, 1973 Plate 14, Figure 8 Hystrichosphaera ramosa var. granomembranacea Davey and Williams, 1966a, Bull. Br. Mus. Nat. Hist. (Geol.) Suppl. 3, p. 37-38, pi. 4, fig. 4. 268 Spiniferites ramosus subsp. granomembranaceus (Davey and Williams, 1966a) Lentin and Williams, 1973, Geol. Surv. Pap. Can., no. 73-42, p. 130. Comments.- Occasional specimens are encountered in the Seymour Island material which compare closely to illustrations of the type material. Some specimens are larger than those reported from the London Clay (Davey & Williams, 1966a). The granular membranes connecting the pro cess bases are occasionally perforated. Dimensions.- Observed range (3 specimens): overall length 53-67p (mean 61.3p); overall width 51-6l|j (mean 56,5|j); endocyst length 42-53p (mean 50.5p); endocyst width 41-47p (mean 46.Op); membrane height to lOp. Stratigraphic occurrence.- Section 3, very rare in samples 8457, 8458, 8465, and 8470; Section 12-13, sparse in sample 8490, rare in samples 8492 and 8494. Spiniferites ramosus subsp. granosus (Davey and Williams, 1966a) Lentin and Williams, 1973 Plate 11, Figures 1-3 Hystrichosphaera ramosa var. granosa Davey and Williams, 1966a, Bull. Br. Hus. Nat. Hist. (Geol.) Suppl. 3, p. 35, pi. 4, fig. 9. Spiniferites ramosus subsp. granosus (Davey and Williams, 1966a) Lentin and Williams, 1973, Geol. Surv. Pap. Can., no. 73-42, p. 130. 269 Comments.- Specimens attributable to this species are well preserved and compare closely with the description of the type material. Intergonal processes have not been observed on any of the specimens. The size range is somewhat broader than that reported by Davey and Williams (1966a). Dimensions.- Observed range (5 specimens): overall length 49-77|J (mean 61.6p); overall width 44-68|j (mean 53.Ip); endocyst length 36-52p (mean 44p); endocyst width 32-44|j (mean 37p); length of processes 8.5-16.5p. Stratigraphic occurrence.- Section 3, very rare in sample 8464. Spiniferites ramosus subsp. multibrevis (Davey and Williams, 1966a) Lentin and Williams, 1973 Plate 12, Figures 1-3; Plate 11, Figures 5, 6 Hystrichosphaera ramosa var. multibrevis Davey and Williams, 1966a, Bull. Br. Mus. Nat. Hist. (Geol.) Suppl. 3, p. 35-36, pi. 1, fig. 4; pi. 4, fig. 6; text-fig. 9. Spiniferites ramosus subsp. multibrevis (Davey and Williams, 1966a) Lentin and Williams, 1973, Geol. Surv. Pap. Can., no. 73-42, p. 130. Comments.- The Seymour Island specimens agree closely with the descrip tion of the type material. Intergonal processes are very rare on all specimens observed. 270 Dimensions.- Observed range (5 specimens): overall length 53-66|J (mean 60.6|j); overall width 39-63p (mean 52.7|j); endocyst length 39-49|J (mean 45.8|j); endocyst width 37-49|J (mean 42.6|j); length of processes up to lip. Stratigraphic occurrence.- Section 3, very rare in sample 8463; Sec tion 19, very rare in sample 8506. Spiniferites ramosus subsp. reticulatus (Davey and Williams, 1966a) Lentin and Williams, 1973 Plate 6, Figure 1 Hystrichosphaera ramosa var. reticulata Davey and Williams, 1966a, Bull. Br. Mus. Nat. Hist. (Geol.) Suppl. 3, p. 38, pi. 1, figs. 2-3. Spiniferites ramosus subsp. reticulatus (Davey and Williams, 1966a) Lentin and Williams, 1973, Geol. Surv. Pap. Can., no. 73-42, p. 130. Comments.- The rare specimens encountered are similar to the description of the type material except the endophragm is distinctly reticulate. The periphragm is granular to reticulate. Davey and Williams (1966a) state the endophragm is smooth and only the periphragm is reticulate on the type material. The rarity of the specimens precludes determining if they are a variant of S. ramosus subsp. reticulatus or a new species. Reworked from Cretaceous (Barremian to Santonian) deposits. 271 Dimensions.- (1 complete specimen recovered): overall length 66.3p; overall width 6l.2|j; endocyst length 51.9m ; endocyst width 44.3p; length of processes up to 8.5p. Stratigraphic occurrence.- Section 3, rare in samples 8451 and 8458, very rare in samples 8460, 8464, 8465, 8467, and 8470; Section 12-13, very rare in sample 8492; Section 17, very rare in samples 8501 and 8502; Section 18, very rare in sample 8504; Section 19, very rare in sample 8508. Spiniferites sp. Comments.- Specimens too poorly preserved to identify at the species level are grouped under Spiniferites sp. Stratigraphic occurrence.- Section 3, rare in samples 8458 and 8479, very rare in samples 8447, 8457, 8462, 8464, and 8477; Section 15, very rare in sample 8495, 8496, and 8497; Section 16, very rare in sample 8499; Section 19, rare in sample 8508, very rare in sample 8512. Genus Tanyosphaeridium Davey and Williams, 1966b Tanyosphaeridium xanthiopyxides (0. Wetzel, 1933b) Stover and Evitt, 1978 Plate 9, Figures 8, 9 Hystrichosphaera xanthiopyxidies 0. Wetzel, 1933b, Palaeontographica, Abt. A, Vol. 78, p. 44, pi. 4, fig. 25. 272 Tanyosphaeridium xanthiopyxides (0. Wetzel, 1933b) Stover and Evitt, 1978, Stanford Univ. Pubis., Geol. Sciences, Vol. 15, p. 85. Comments.- Some Seymour Island specimens have more processes than reported for the type material (20-35 processes). The dimensions, sculpture and process structure compare closely with the description of the type material. Dimensions.- Observed range (2 specimens): central body length 28.7|J (only measurable on one specimen); central body width 21-25^ (mean 23|j); length of processes 13-l6|j; wall approximately 1.5(J thick. Stratigraphic occurrence.- Section 15, very rare in sample 8495. Genus Thalassiphora Eisenack and Gocht, 1960 emend. 1968 Thalassiphora pelagica (Eisenack, 1954) Eisenack and Gocht, 1960 Plate 15, Figure 10 Pterospermopsis pelagica Eisenack, 1954, Palaeontographica, Abt. A, vol. 105, p. 71, pi. 12, figs. 17-18. Thalassiphora pelagica (Eisenack, 1954) Eisenack and Gocht, 1960, Neues Jahrb. Geol. Palaontol., Mh., p. 513-514. Comments.- The pericyst's delicate structure and originally subspherical shape of both the pericyst and the endocyst have resulted in specimens of Thalassiphora pelagica specimens being deposited, compressed and fos silized in various orientations. Dorsal-ventral, right lateral, left 273 lateral and antapical orientations have all been observed. The dorsal- ventral orientation is the most favorable for study because it generally provides a clear view of the archeopyle and the antapical projection. The circular outline of the fibrous, reticulate periphragm is inter rupted only by the short, antapical projection. The thin periphragm (<0.5m ) appears to have been originally highly perforated. Many speci mens bear square and rhombodial scars and perforations of mineral crys tals, probably pyrite and/or calcite. The thicker endophragm (1 to 2.5p) is subcircular in outline and solid in structure. Occasional crystal impressions have been observed on the endophragm; none, however, appear to have perforated the endocyst. The precingular archeopyle (3P) is large (approximately 40m wide) and dominates the anterior dorsal surface of the endocyst. The sizes of the Seymour Island specimens compare closely with those reported for the type material (Eisenack, 1954) and those from southern England (Williams, 1963). Dimensions.- Observed range (5 specimens): pericyst length 174-213p (mean 188.6p); pericyst width 168-227|J (mean 174.5p); endocyst length 83-106|j (mean 95.Ip); endocyst width 71-87p (mean 80.4m ); archeopyle dimensions (2 specimens), length 31-46fJ (mean 39.5p); width 36-39|J (mean 37.5m ). 274 Stratigraphic occurrence.- Section 3, very rare in samples 8463 and 8468; Section 17, very rare in samples 8500 and 8501. Thalassiphora velata (Deflandre and Cookson, 1955) Eisenack and Gocht, 1960 Plate 15, Figures 1, 4, 7 Pterocystidiopsis velata Deflandre and Cookson, 1955, Aust. Jl. Mar. Fresh. Res., Vol. 6, p. 291, pi. 8, fig. 8. Thalassiphora velata (Deflandrea and Cookson, 1955) Eisenack and Gocht, 1960, Neues Jahr. Geol. Palaont., Mont., p. 514-515. Comments.- The distinctive fibrous strands connecting the endophragm and the periphragm, and the absence of a tail-like antapical projection on the periphragm serve to distinguish Thalassiphora velata from T. pelagica (Cookson and Eisenack, 196lb). Both morphologic features are evident on the Seymour Island specimens of T. velata. Distinctive protuberances of the endophragm occur where the fibrous strands arise at the apical and antapical poles. The endophragm is finely granular, whereas the periphragm is fibrous to slightly reticulate. It is not strongly reticulate like the periphragm of T. pelagica. The archeopyle is precingular. The paracingulum is indicated on most specimens by a fold running across the endocyst just below the archeo pyle. 275 Dimensions.- Observed range (2 measurable specimens); pericyst diameter ll4-176p (mean 145|j); endocyst diameter 66-95p (mean 80.5p); periphragm less than 1|J thick; endophragm approximately 2.Op thick. Stratigraphic occurrence.- Section 3, very rare in samples 8465, 8466, 8467, and 8468. Genus Trigonopyxidia Cookson and Eisenack, 1961a Trigonopyxidia ginella (Cookson and Eisenack, 1960a) Downie and Sarjeant, 1965 Plate 16, Figure 16 Trigonopyxis ginella Cookson and Eisenack, 1960a, Micropaleo., Vol. 6, No. 1, p. 11, pi. 3, figs. 18-20. Trigonopyxidia ginella (Cookson and Eisenack, 1960a) Downie and Sar jeant, 1965, Palaeontology, Vol. 6, p. 149. Comments.- Only one specimen was recovered. It was identical to the description and illustrations of the type material, except the surface is shagreenate instead of smooth. Archeopyle margin smooth, without accessory parasutures. No indication of a paracingulum or parasulcus. Dimensions.- (1 specimen): periphragm width 55p; periphragm length 50p (without operculum); periphragm thickness lp; endophragm unmeasurable due to folding. Stratigraphic occurrence.- Section 15, very rare in sample 8497. 276 Genus Turbiosphaera Archangelsky, 1969a Turbiosphaera filosa (Wilson, 1967a) Archangelsky, 1969a Plate 12, Figures 16-18 Cordosphaeridium turbiosphaera Wilson, 1967a, N.Z. Jl. Bot., Vol. 5, p. 66, figs. 2, 31-32 and 34. Turbiosphaera filosa (Wilson, 1967a) Archangelsky, 1969a, Ameghiniana, Vol. 5, p. 408-411. Comments.- Identical to the description of the type material from McMurdo Sound, Antarctica (Wilson, 1967a). Two complete and a few frag mentary specimens recovered. Dimensions.- Observed range (2 complete specimens): pericyst length 95-102p (mean 98.6p); pericyst width 6l-62p (mean 61.5p); pericyst thickness less than lp; endocyst length 64-74p (mean 69p); endocyst width 47-5lp (mean 49p); endocyst thickness 1-2.5p. Stratigraphic ocurrence.- Section 3, very rare in samples 8457, 8462, 8464, and 8467. Genus Vozzhennikovia Lentin and Williams, 1976 Vozzhennikovia apertura (Wilson, 1967a) Lentin and Williams, 1976 Plate 7, Figures 1-4 Spinidinium aperturum Wilson, 1967a, N.Z. Jl. Bot., Vol. 5, No. 1, p. 64-65, figs. 3-5, 8. 277 Vozzhennikovia apertura (Wilson, 1967a) Lentin and Wilson, 1976, Bedford Instit. Oceanography Sept. BI-R-75-16, p. 65. Comments.- This species and Vozzhennikovia rotunda (Wilson, 1967a) Lentin and Williams, 1976 are very similar and can be difficult to dif- ferntiate in assemblages which contain large populations of these forms. Wilson (1967a) felt V. apertura was characterized by "the relatively large size of the archeopyle, transverse girdle (paracingulum) and logi- tudinal furrow (parasulcal groove)." V. rotunda was distinguished from V. apertura "by its circular outline, discontinuous girdle (para cingulum), thinner-walled, single-layered shell (dinocyst), smaller finer spines and by its generally larger size." Wilson (1967a) noted that a few intermediate forms had been observed in some of his material. These two species cannot be differentiated on the basis of their archeo pyle types because they both have a standard hexa 2a archeopyle (Lentin and Williams, 1976). Spine length and overall dinocyst size were likewise of little use in species differentiation. Both species exhibited overlapping ranges in the dimensions of these two characteristics. Similarly the number of wall layers was not diagnostic because both species have a periphragm and an endophragm (Lentin and Williams, 1976). Dinocyst shape is diagnostic, as described by Wilson (1967a). However, the vagaries of preservation and the inherent range in shape observed in these species all but precluded the use of dinocyst shape as a 278 diagnostic feature. Well preserved specimens identical to the type spe cimens of each species could, of course, be differentiated. The characteristics of the paracingulum and the parasulcal groove, as described by Wilson (1967a), were useful in differentiating V. aperatura and V. rotunda. However, preservation and morphologic variability were again important; only the best preserved specimens and those closely approximating the type specimens of each species could be identified easily. I believe these two species belong to a morphologic continuum; probably they are the same species. However, additional assemblages and the type specimens of each species must be studied before it can be determined whether the two species are synonymous. Dimension.- Observed range (10 specimens): overall length 32-58p (mean 41.7p); overall width 32-46p (mean 38.Op). Stratigraphic occurrence.- Section 3, abundant in samples 8447 and 8453, sparse in samples 8452, 8462, 8463, 8470, 8471, 8477, and 8478, rare in samples 844, 8469-8471, 8475, 8477, and 8478, rare in samples 8449, 8451, 8456, 8465, and 8469, very rare in samples 8455, 8464, and 8475; Section 18, very rare in sample 8504; Section 19, rare in samples 8510 and 8511, very rare in samples 8506 and 8509. 279 Vozzhennikovia rotunda (Wilson, 1967a) Lentin and Williams, 1976 Plate 7, Figures 6-8 Spinidinium rotundum Wilson, 1967a, N.Z. Jl. Bot., Vol. 5, No. 1, p. 65-66, figs. 6 and 7. Vozzhennikovia rotunda (Wilson, 1967a) Lentin and Williams, 1976, Bed ford Instit. Oceanography Rept. BI-R-75-16, p. 67. Comments.- Vozzhennikovia rotunda is discussed and compared with V, apertura in the treatment of the latter species. It should be emphasized that the parasulcal groove is not always clearly indicated; often it is not evident at all. The paracingulum is faintly indicated, if at all. The length of the spines varies considerably, ranging from less than 1|J to 5|J. Host spines are capitate. The longer spines are hollow proxi- mally and a basal ring is evident where the spine abuts the dinocyst body. Dimensions.- Observed range (10 specimens): overall length 34-45p (mean 39.9m ); overall width 30-39p (mean 34.2m )> Stratigraphic occurrence.- Section 3, abundant in samples 8454, 8456, 8458, 8463, 8476, and 8477, common in samples 8450, 8465, and 8472, sparse in samples 8443, 8451, 8465, and 8472, sparse in samples 8443, 8451, 6453, 8457, 8468, 8470, 8471, 8473, 8474, and 8475, rare in sam ples 8444, 8446, 8452, 8460, 8462, 8464, 8467, and 8469, very rare in 280 samples 8447-8449, 8466, and 8478; Section 12-13, sparse in samples 8486 and 8490, very rare in 8481 and 8488; Section 17, sparse in samples 8501 and 8502, rare in sample 8500; Section 18, common in sample 8504, sparse in sample 8505, rare in sample 8503; Section 19, abundant in sample 8507, 8511, and 8512, common in sample 8506, sparse in sample 8508. Genus Xylochoarion Erkman and Sarjeant, 1978 Xylochoarion cf. backnessense Erkman and Sarjeant, 1978 Plate 9, Figures 12, 13 Xylochoarion hacknessense Erkman and Sarjeant, 1978, N. Jb. Geol. Palaont. Mb., p. 404, 406-407, text-figs. 1-11. Comments.- One specimen was recovered which agrees fairly well with the description of the type material. The major exception is that the Seymour Island specimen is approximately one-half the size of the speci mens reported by Erkman and Sarjeant (1978). The hundreds of nontabular solid processes are capitate, symmetrically bifurcate or asymmetrically bifurcate distally. There is a distinct basal thickening where the processes join the central body. Reworked from the late middle Jurassic (Callovian). Dimensions.- (1 specimen recovered, operculum missing): length 23p; width 20|j; process length 5-10p; wall thickness approximately lp. Stratigraphic occurrence.- Section 3, very rare in sample 8467. 281 Group ACRITARCHA Evitt, 1963 Genus Baltisphaeridium Eisenack, 1958 emended Downie and Sarjeant, 1963 Baltisphaeridium ligospinosum DeConnick, 1969 Plate 12, Figures 9, 10 Baltisphaeridium ligospinosum DeConnick, 1969, Instit. Royal Sci. Natur. Belgique, Prof. Paper No. 12, p. 50, pi. 15, figs. 9-19. Comments.- The numerous Bolid processes, overall size and process dimen sions agree closely with illustrations of the type material from the Kallo borehole (DeConnick, 1969). The process terminations are asymmetrically bifurcate, as in type material; however, acuminate tips are also present. No openings were observed in any specimens. Dimensions.- Observed range (10 specimens): main body diameter 17-18p (mean 23.5p); process length 7-lOfi; process diameter 0.5p. Stratigraphic occurrence.- Section 3, rare in samples 8457 8466, very rare in samples 8459 and 8464, abundant in sanq>les 8468, 8472, and 8475; Section 12-13, very rare in sample 8481; Section 15, rare in all sam ples; Section 17, abundant in sample 8500; Section 18, rare in sample 8503; Section 19, very rare in samples 8506, 8511, and 8512. 282 Genus Comasphaeridimn Staplin, Jansonius and Focock, 1965 Comasphaeridium coroetes (Valensi, 1948) DeConinck, 1969 Plate 9, Figures 4, 5 Michrystridium cometes Valensi, 1948, Bull. Soc. geol. France, Vol. 5, No. 18, p. 547, Fig. 5 (illustration #6). Comasphaeridium cometes (Valensi, 1948) DeConinck, 1969, Inst. Roy. Sci. Natur. Belg., Mem. 161, p. 58, pi. 16, fig. 34-41. Comments.- Subspherical to elliptical central body bearing hundreds of short, solid hairlike spines. The spines are acicular. No openings observed in the wall of the central body. The Seymour Island specimens compare closely with the illustrations of the type material (Valensi, 1948) and the specimens reported by DeCon inck (1969) from the Kallo borehole. Dimensions.- Observed range (5 specimens): central body length 20-29|J (mean 22.9|j); width central body 15-22p (mean 18.4(j); process length 2-5|J; wall thickness approximately 0.5JJ. Stratigraphic occurrence.- Section 3, rare in sample 8449, very rare in sample 8458; Section 12-13, very rare in samples 8493 and 8494; Sec tion 16, very rare in sample 8499; Section 19, very rare in sample 8506. 283 Genus Leiofusa Eisenack, 1938 Leiofusa jurassica Cookson and Eisenack, 1958 Plate 16, Figure 12 Leiofusa jurassica Cookson and Eisenack, 1958, Proc. Roy. Soc. Victoria, Vol. 70, p. 51, pi. 10, figs 3-4. Comments.- A single specimen bearing a strong resemblance to Leiofusa jurassica was recovered. It differed from the description of the type material in having a transverse fold (?paracingulum) and solid polar spines. No opening in the test wall. The hollow test is closed off at the base of both spines. Each spine base has two or three spindle-shaped hollow areas aligned along the axis of the spine. All areas are less than 0.7p long. These areas are sepa rated by solid wall material and may be the result secondary thickening similar to that reported in Veryhachium domasia and some species of Diexallophasis (Downie, 1979). Dimensions(1 complete specimen recovered): overall length 35.7p; test length 23|J; test width 12.6|i. Stratigraphic occurrence.- Section 3, very rare in sample 8475; Sec tion 17, very rare in sample 8502. 284 Genus Micrhystridium Deflandre, 1937 emend. Downie and Sarjeant, 1963 Micrhystridium sp. A. Plate 9, Figures 10, 11 Comments■- Subcircular to ellipsoidal test bearing numerous solid spines. The spines are acuminate and up to 8|i long. Most specimens were enrolled around the longitudinal or transverse axis and looked like a ball of processes. Dimensions.- Observed range (5 specimens): central body length 16-33|J (mean 22.2|j); central body width 12-26|J (mean 16.8p); processes up to 8p long. Stratigraphic occurrence.- Section 3, sparse in sample 8457, rare in samples 8444 and 8461, very rare in samples 8447, 8458, 8464, 8472, 8474, 8475, 8476, and 8479; Section 19, rare in sample 8511, very rare in sample 8512. Genus Ophiobolus 0. Wetzel 1933a emend. Evitt 1968 Ophiobolus lapidaris 0. Wetzel 1933a Plate 16, Figure 10 Ophiobolus lapidaris 0. Wetzel, 1933a, Palaeontolgraphica, Vol. 76, p. 167-179, pi. 2, figs. 3034, text-fig. 5-7. Comments.- Ophiobolus lapidaris 0. Wetzel was discussed in minute detail by Evitt (1968). The surface ornamentation ranges from smooth to very 285 finely granulate on the Seymour Island specimens. The latter ornamenta tion is often difficult to see, as Evitt (1968) noted. The number of processes or strands varies from one to five on the Antarctic specimens. Dimensions.- Observed range (6 specimens): body length 18-30p (mean 22.5m )> body width 15 x 22p (mean 19.4m ); wall thickness approximately 0.5M. Stratigraphic occurrence.- Section 3, rare in samples 8460, 8461, 8473, and 8475, very rare in samples 8443, 8449, 8456, 8457, 8458, 8463, 8464, 8465, 8466, 8468, 8470, and 8479; Section 15, very rare in sample 8496; Section 16, rare in sample 8498; Section 18, rare in samples 8501 and 8502, very rare in sample 8500; Section 19, rare in sample 8503, very rare in samples 8504 and 8506. Genus Veryhachium (Denuff, 1958) emend. Downie and Sarjeant, 1963 Veryhachium sp. Comments.- Triangular forms bearing a hollow horn at each corner were observed on rare occasions. The wall is smooth, thin, and colorless. One side of the triangular body is half as long as the other two sides. No opening was observed in the wall. Dimension.- (1 complete specimen recovered): overall length 55m ; overall width 42.9m ; test length 34.1m ; test width 26.4m ; horn length approximately 20m ; wall thickness <0.5m - 286 Stratigraphic occurrence.- Section 3, very rare in samples 8447 and 8457; Section 18, very rare in sample 8503. Division PRASINOPHYTA Round Order PTEROSPERMATALES Schiller Family CYMATIOSPHAERACEAE Madler Genus Cymatiosphaera (0. Wetzel 1933b) Deflandre 1954 Cymatiosphaera sp. Plate 16, Figures 7-9 Very rare, widely scattered specimens of Cymatiosphaera were recovered from Sections 3, 15, 16, and 19, Their distribution seemed to preclude any stratigraphic application in the sections studied and, like McLean (1971), specific identification was not attempted. McLean (1971) noted that some of his specimens (which were also rare) occurred in deposits believed to have been deposited under subnormal marine paleoenvironmental conditions. Family PTEROSPERMELLACEAE Eisenack Genus Pterospermella Eisenack, 1972 Pterospermella australiensis (Deflandre and Cookson, 1955) Eisenack, 1972 Plate 16, Figure 11 Pterospermopsis australiensis Deflandre and Cookson, 1955, Austral. J. Mar. Freshw. Res., Vol.6, p. 286, pi. 3, fig. 4, text-figs. 52 and 53. 287 Pterospermella australiensis (Deflandre and Cookson, 1955) Eisenack, 1972, N. Jb. Geol. Palaont. Mh., p. 596-601. Comments.- The rare specimens recovered from Seymour Island compare well with the illustrations of the type material. They differ only in being slightly larger than the Australian specimens. Dimensions(1 example specimen recovered): overall length 55p; overall width 44p; inner body length 26.4|j; inner body width 17.6|j; both wall layers <0.5|J thick. Stratigraphic occurrence.- Section 3, very rare in samples 8458, 8478, and 8479. Division CHL0R0PHYTA Pasher Class CHLOROPHYCEAE Kiitzing Order CHL0R0C0CCALES Marchand 1895 orth. mut. Pasher Family CHLOROCOCCACEAE Blackman and Tansley Genus Palambages 0. Wetzel, 1961 Palambages morulosa 0. Wetzel, 1961 Plate 16, Figure 3 Palambages morulosa 0. Wetzel, 1961, Hicropaleo., Vol. 7, No. 3, p. 338, pi. 1, fig. 11. Comments.- The specimens included in P. morulosa consist of many subcir cular bodies, as in the Baltic type material (Wetzel, 1961). The ratio of the maximum diameter of the individual bodies to the maximum diameter 288 of the entire colony is the Diameter Index (DI). P. morulosa has a D1 which ranges from 0.10 to 0.23 (mean 0.17; 6 specimens measured). The surface of the individual bodies is smooth and nonuniformly foveo- late. Pitting is especially evident along interbody walls. Wall thick ness is less than 1|J, as measured on the outside wall of a peripheral body. The wall thickness between abutting bodies within the colony is up to 2.5p thick. Such interbody walls are much darker than the peri pheral walls and the rest of the colony. Ragged openings (tears?) were noted in some individual bodies. The thick wall surface, DI and the thick interbody boundary walls dis tinguish these forms from P. Forma B Manum and Cookson, 1964 and P. Type I. Dimensions.- Observed range (5 specimens): overall length 77-153p (mean 121.Op); overall width 68-105p (mean 97.2p); individual body dimensions: overall length 12-20p (mean 19.4p); overall width 12-19p (mean 18.4p). Stratigraphic occurrence.- Section 3, rare in samples 8450 and 8464, very rare in samples 8443, 8447, 8456, 8457, 8460, 8462, 8465, 8470, 8472, 8473, 8477, 8478, 8479; Section 12-13, abundant in sample 8483, rare in sample 8490; Section 15, very rare in sample 8497; Section 19, very rare in sample 8510. 289 Palambages Forma B Manum and Cookson, 1964 Plate 16, Figures 1, 2 Palambages Forma B Manum and Cookson, 1964, Skr. Norske Vid. Akad. I Mat. Nat. Kl., N. Ser. 17, p. 24, pi. 7, fig. 8. Comments.- The eight individual bodies making up the colony are subcir cular and coarsely granulate. Granulation occurs in randomly shaped clumps and as individual grains. Body walls approximately 1|J thick. The DI = 0.52 (see DI definition under discussion of P. morulosa) and greatly exceeds that of P. morulosa and P. Type I. Whether this is characteristic of P. Forma B remains to be seen, because only one spe cimen was observed. Large, angular openings were observed in four of the bodies making up the colony. They did not resemble the openings P. morulosa described by Gocht and Wille (1972). This species is not considered to be synonymous with P. morulosa, as suggested by Gocht and Wille (1972), because of 1) the large ratio between the individual body and the colony diameters, 2) the large, angular opening in the individual bodies, and 3) the coarsely granular nature of the ornamentation. Dimensions.- Observed range (2 specimens): diameter 67-102p (mean 84.5p); diameter of individual bodies 28-35p (mean 31.5p). Stratigraphic occurrence.- Sections 12-13, very rare in sample 8485. 290 Palambages Type I Plate 16, Figures 4-6 Description.- Subcircular colonies formed by numerous smaller subcir cular bodies. Each colony appears to have been a hollow sphere prior to compaction, the smaller bodies forming the wall. The exact number of constituent bodies could not be determined accurately because of the intricate wall structure. Each small body is composed of a skeletal network of strands, similar in principle to Evittosphaerula paratabulata Manum, 1979. (P. Type I and E. paratabulata are not synonymous.) The smooth to rough strands are round to subelliptical in cross-section and up to l.Sp wide. No parata- bulation formulae was evident. A shagreenate, 0.5|J thick membrane covers the skeletal framework, forming the body wall. The constituent bodies appear to be united by strands external to the wall membrane. A wall opening not unlike that described for P. morulosa (Gocht and Wille, 1972) was observed in one constituent body. It is not clear whether this is a characteristic opening or an artifact. Comments.- The structure of these colonies indicates a relationship to Palambages, whereas the structure of the constituent bodies excludes them from P. morulosa. 291 Dimensions.- Observed range (5 specimens): overall length 90-131|J (mean 101.6p); overall width 71-lllp (mean 67.Op); diameter of the individual bodies 19-34p (mean 25.Ip). Stratigraphic occurrence.- Section 3, common in sample 8454, rare in sample 8455, very rare in samples 8449, 8456, 8458, 8460, 8463, 8467, and 8479; Section 17, very rare in sample 8502; Section 19, rare in sample 8508. Family B0TRY0C0CCACEAE N. Wille Genus Botryococcus Kiitzing 1849 Botryococcus sp. Plate 16, Figure 15 Comments.- Rare colonies of Botryococcus were encountered which agree with the detailed descriptions of Blackburn (1936). Colonies generally consist of 10 to 20 cells. Stratigraphic occurrence.- Section 3, rare in sample 8452, very rare in samples 8445 and 8475; Section 19, very rare in sample 8512. APPENDIX B - SAMPLE MATERIAL AND PREPARATION Sample Material The location of each section and the distribution of the samples within the sections are shown in text-figures 58 and 59, respectively. Detailed stratigraphic sections for Seymour Island have been presented by Trautman (1976). The lithologic characteristics of each sample are given in Appendix C. Palynological Sample Preparation The procedures used to prepare samples for palynological examination (Table 21) were based upon those employed by the Geological Survey of Canada (Barss and Williams, 1973; Barss and Crilley, 1976). One reference slide of untreated material was prepared prior to acid digestion of each sample. Variations of the preparation scheme presented in Table 21 were followed when the sample residue characteristics indicated the necessity for doing so. For example, samples not requiring oxidation were cleaned by heavy liquid separation directly after 20^ screening, or solubilized samples might not require heavy liquid separation, but the resulting chemical diminution of the macerals might necessitate rescreening to remove unwanted debris. In short, each sample was processed with the steps necessary to extract the most complete palynological assemblage. 292 293 SEYMOUR ISLAND Text-figure 58. Map depicting the locations of the stratigraphic sec tions on Seymour Island. 294 12-13 ... 15 16 17 ie S24hv 143m- 123m - 131m=, 164m' 00m- 156ffi T 19 K12 hW3 . hB4B7 •511 .9494 •499 •02 150 - •4(2 1506 S4M * 1 6 0 - 150 - M l no4 M 9 100 W “- m 1 00 - 5 0 - - E10 •411 -9503 IMS •464 •411 •471 100 94® M 3 -9509 M l -0502 1452 1 0 0 - <9493 ■9492 9490 100 •503 1 0 0 ' MO M l -94(1 •441 - 50 250- 5 0 - .9459 •460 (479 •4 ® 6 0 - .M 6 -9601 50- 5 0 - MB -KOI 200 - M 2 I-Ml ' BOB •416 •474 •445 •407 Text-figure 59. Location of the samples within the sections. TABLE 21 PALYNOLOGICAL SAMPLE PROCESSING PROCEDURE ROCK SAMPLE TOTAL SAMPLE (5-10 GRAMS) SLIDE (1) 10*/. HCl DECANT A WASH (3 TIMES) CONCENTRATED HF DECANT A HASH . (3 TIMES) CONCENTRATED HOT HCl DECANT A NASH SOURCE SLIDES (21 (3 TIMES) SCREEN (20jj) MACERAL SLIDES (2) OXIDIZE- <10*/. HN03) CENTRIFUGE A WASH SOLUBILIZE IS'/. HN ,0H) CENTRIFUGE * WASH SCREEN (20JJ) UNTIL CLEAR HEAVY LIQUID ZnCl WASH STAINING AND/OR STORE RESIDUE SLIDE MAKING 296 TOC sample preparation: Standard processing procedures (Table 22) were used for TOC sample prep aration Five to seven grams of sample were disaggregated; some required grinding with mortar and pestle. TABLE 22 TOTAL ORGANIC CARBON SAMPLE PREPARATION PROCEDURE SAMPLE GRIND FILTER (WHATMAN 541 FILTER PAPER) DRY (EIGHT HOURS AT 40*C HEIGH ANALYZE ILECO CASOMETRIC CARBON ANALYZER) APPENDIX C - DATA Introduction This appendix contains tabulations of raw data counts, TOC measurements, and microscopic lithologic descriptions of the samples. TOC, micro- plankton, spore-pollen, and maceral counts are presented by section in Tables 2 through 5, occurring in the pocket inside the back cover. Lithologic Characteristics of the Sample Material A binocular microscope was used to examine the study samples. The fol lowing data were recorded: 1) Lithology 2) Type of cement, if present 3) Color (fresh surface if possible) 4) Presence of: a) gypsum b) glauconite c) pyrite d) jarosite e) limonitic staining 5) Macrofossils (presence-absence) 6) Calcareous nature of sample "Glauconite" is used in a descriptive sense and refers to green sub- spherical pellets observed under the microscope; their precise mineralo- gical composition was not determined. 298 299 The samples are arranged by section and in stratigraphic order, begin ning at the base of each section. Laboratory processing numbers (A) and field sample numbers (B) are listed along the left margin. The height of each sample above the base of the section is shown along the right margin. 300 Section 3 Meters Above A B ______Lithologic Description______Section Base 8457 SI-120-01-75 Very fine sand. Yellowish olive 0.0 gray (5Y6/2). Glauconitic. Noncalcareous. 8458 SI-123-01-75 Very fine sand. Medium olive gray 47.1 (5Y5/1). Glauconite and jarosite. Carbonized wood. Noncalcareous. 8460 SI-124-02-75 Fine sandstone, granules common. 77.0 Calcite cement. Light olive gray (5Y5/2). Limonitic staining. Glauconite. Pelecypods. Calcareous. 8459 SI-124-01-75 Pebblestone with very fine to 77.3 coarse sand matrix. Calcite cement. Color variegated with pale olive (10Y6/2) matrix. Limonitic staining. Glauconite. Pelecypods. Calcareous. 8461 SI-125-01-75 Fine sandstone. Calcite cement. 97.5 Light olive gray (5Y6/1). Glauconite. Calcareous. 301 Section 3 (continued) Meters Above A B ______Lithologic Description______Section Base 8462 SI-126-01-75 Fine to medium sand. Medium olive 102.9 brown (5Y5/4). Glauconite. Noncalcareous. 8463 SI-127-01-75 Very fine to fine sandstone. 103.6 Calcite cement. Medium olive gray (5Y5/1). Glauconite. Calcareous. 8464 SI-127-02-75 Fine sandstone with very coarse 104.4 sand grains scattered throughout. Calcite cement. Medium greenish gray (5G5/1). Glauconite. Calcareous. 8465 SI-128-01-75 Very fine sand. Light olive gray 116.6 (5Y6/1). Glauconite and jarosite. Noncalcareous. 8466 SI-129-01-75 Very fine sandstone. Calcite 128.9 cement. Medium olive gray (5Y5/1). Glauconite. Calcareous. 8468 SI-130-02-75 Very fine sand. Light olive gray 132.9 (5Y5/2). Glauconite and jarosite. Carbonized wood. Noncalcareous. 302 Section 3 (continued) Meters Above A B ______Lithologic Description______Section Base 8467 SI-130-01-75 Very fine sand. Yellowish gray 133.0 (5Y7/2). Glauconite and jarosite. Abundant carbonized wood. Noncalcareous. 8471 SI-131-03-75 Burrowed wood. 136.3 8470 SI-131-02-75 Muddy-fine sandstone. Calcite 136.4 cement. Dark olive gray (5Y3/1). Glauconite. Calcareous. 8469 SI-131-01-75 Very fine sandstone. Calcite 137.1 cement. Medium olive gray (5Y5/1). Glauconite. Limonitic staining. Pelecypod fragments. Calcareous. 8443 SI-101-01-75 Very fine sandstone. Calcite 137.2 cement. Dark olive gray (5Y3/1). Burrow tubes approximately 2ran in diameter. Calcareous. 8472 SI-132-01-75 Very fine sand. Light olive gray 154.5 (5Y5/2). Glauconite and limonitic staining. Noncalcareous. 8473 SI-132-02-75 Fossilized wood. 162.3 303 Section 3 (continued) Meters Above _B______Lithologic Description___ Section Base 8445 SI-105-02-75 Very fine sandstone. Calcite 164.4 cement. Yellowish gray (5Y8/1). Glauconite. Turritella sp. Calcareous. 8444 SI-105-01-75 Fine sandstone. Calcite cement. 164.5 Light olive brown (5Y5/6). Glauconite. Cucullea sp. Calcareous. 8446 SI-106-01-75 Very fine sandstone. Calcite 167.6 cement. Light olive gray (5Y6/1). Glauconite. Calcareous. 8474 SI-135-01-75 Interbedded siltstone and fine 168.0 sandstone. Dark olive gray (5Y3/1) siltstone and medium gray (N5) sandstone. Glauconite. Mollusc shell fragments. Calcareous. 8475 SI-136-01-75 Very fine sand. Medium olive gray 177.1 (5Y5/1). Glauconite and jarosite. Carbonized wood fragments (rare). Noncalcareous. 304 Section 3 (continued) Meters Above A B ______Lithologic Description______Section Base 8476 SI-138-01-75 Siltstone. Medium olive gray 237.8 (5Y5/1). Glauconite and jarosite. Noncalcareous. 8447 SI-110-01-75 Fine sandstone. Calcite cement. 251.0 Medium dark gray (N4). Turritella sp. Calcareous. 8449 SI-111-02-75 Fine sandstone. Calcite cement. 258.0 Medium dark gray (N7). Glauconite. Turritella sp. Calcareous. 8448 SI-111-01-75 Very fine sandstone. Calcite 258.1 cement. Medium dark gray (N4). Glauconite. Gastropod fragments. Calcareous. 8450 SI-111-03-75 Fine sandstone. Calcite cement. 258.8 Medium greenish gray (5Y5/1). Glauconite. Calcareous. 8452 SI-112-02-75 Fine sandstone. Calcite cement. 266.3 Medium olive gray (5Y5/1). Glauconite. Pelecypod and gastropod fragments. Calcareous. 305 Section 3 (continued) Meters Above A B ______Lithologic Description______Section Base 8451 SI-112-01-75 Fine sandstone. Calcite cement. 266.4 Medium olive gray (5Y5/1). Glauconite. Calcareous. 8453 SI-113-01-75 Fine sandstone. Calcite cement. 273.4 Dusky yellow (5Y6/4). Glauconite. Pelecypod fragments. Calcareous. 8477 SI-148-01-75 Mud. Light olive gray (5Y6/1). 281.2 Glauconite and jarosite. Noncalcareous. 8478 SI-148-02-75 Fine medium sand. Greenish gray 282.5 (5GY6/1). Glauconite and jarosite. Noncalcareous. 8454 SI-115-01-75 Medium sandstone. Calcite cement. 284.4 Light gray (N7). Glauconite. Calcareous. 8479 SI-150-01-75 Mud. Dark olive gray (5Y3/1). 289.6 Glauconite and jarosite. Noncalcareous. 306 Section 3 (continued) Meters Above A B ______lithologic Description Section Base 8455 SI-116-01-75 Muddy fine sandstone. Calcite 292.2 cement. Medium gray (N5). Glauconite. Mollusc shell fragments. Calcareous. 8456 SI-118-01-75 Fine sandstone. Calcite cement. 302.7 Medium light gray (N6). Glauconite. Mollusc shell fragments. Calcareous. 307 Section 12-13 Meters Above _B______Lithologic Description______Section Base 8480 SI-301-01-75 Muddy medium to coarse sand. 3.4 Dusky yellow (5Y6/4). Jarosite content high. Carbonized wood fragments, some coated with pyrite. Noncalcareous. 8481 SI-301-02-75 Muddy fine to very coarse sand; 8.4 some granules present. Light olive yellow (5Y5/4). Highly glauconitic. Traces of carbonized wood. Noncalcareous. 8482 SI-301-03-75 Medium to very coarse sandstone 13.7 with granules common. Poorly cemented with siderite. Moderate olive brown (5Y4/6) mottled with dusky red (5R3/4). Glauconite and pyrite common. Calcareous. 308 Section 12-13 (continued) Meters Above _B______Lithologic Description___ Section Base 8484 SI-301-05-75 Medium to very coarse sand. 21.3 Moderate yellow (5Y7/6) to pale olive (10Y6/2). Gypsum clasts bound together by stiff, jarosite rich mud. Carbonized wood fragments common; up to 1 cm long. Wood often coated with iron sulfide. 8483 SI-301-04-75 Medium to very coarse sand with 24.4 granules. Mud binder. Light olive gray (5Y5/2). Pyrite and glauconite. Slightly calcareous. 8486 SI-302-02-75 Medium to very coarse sandstone 42.7 with granules. Mud binder. Moderate pale yellow (10Y7/2). Pyrite and glauconite. Carbonized wood with pyrite coating. Slightly calcareous. 8485 SI-302-01-75 Sandy siltstone. Yellowish gray 42.8 (5Y8/1). Noncalcareous. 309 Section 12-13 (continued) Meters Above Lithologic Description______Section Base 8487 SI-302-03-75 Medium to very coarse sand, with 75.1 some granules present. Yellowish gray (5Y8/1). Jarosite crusts and pyrite grains. Carbonized wood, some coated with pyrite. Calcareous. 8488 SI-302-04-75 Medium to very coarse sand bound 111.6 by mud. Grayish yellow (5Y8/4). Gypsum and jarosite. Carbonized wood fragments (up to 10mm long) coated with iron sulfide. Noncalcareous. 8489 SI-303-01-75 Stiff mud, with clasts to coarse 121.6 sand size scattered throughout. Moderate yellow (5Y7/6) to pale olive (10Y6/2). Jarosite mixed throughout mud. Noncalcareous. 8491 SI-304-02-75 Bone fragment. 130.1 310 Section 12-13 (continued) Meters Above B______Lithologic Description______Section Base 8490 SX-304-01-75 Siltstone, semilithified. Light 130.2 olive gray (5Y6/1). Gypsum and jarosite on weathered surfaces. Carbonized wood fragments present. Rare sponge spicules. Noncalcareous. 8492 SI-304-03-75 Fine to medium sandstone, poorly 132.4 lithified. Light olive gray (5Y6/1). Gypsum and jarosite present on aggregate chunks. Limonitic staining. Slightly calcareous. 8493 SI-304-04-75 Silty, very fine sand. Yellowish 136.5 gray (5Y7/2). Glauconite. Jarosite abundant. Carbonized wood abundant, some pyrite coated. Noncalcareous. 8494 SI-304-05-75 Sandy siltstone. Light gray (N7). 136.6 Jarosite. Carbonized wood (up to 4 cm long). Noncalcareous. 311 Section 15 Meters Above _B______Lithologic Description Section Base 8495 SI-306-01-75 Fine to medium sand. Light olive 33.5 gray (5Y5/2). Glauconite and jarosite. Noncalcareous. 8496 SI-306-02-75 Medium sand. Light olive gray 59.6 (5Y6/1). Glauconite and jarosite present. Carbonized wood, some coated with pyrite. Noncalcareous. 8497 SI-306-03-75 Fine sand. Light olive gray 120.6 (5Y6/1). Glauconite and pyrite. Carbonized wood, some coated with pyrite. Noncalcareous. 312 Section 16 Meters Above B______Lithologic Description Section Base 8498 SI-307-01-75 Fine to medium sand. Dusky yellow 25.9 (5Y6/4). Glauconite and jarosite. Carbonized wood. Noncalcareous. 8499 SI-308-02-75 Medium to very coarse sand. Dusky 79.4 yellow (5Y6/4). Glauconite and jarosite. Carbonized wood (up to 7mm long). Noncalcareous. 313 Section 17 Meters Above B ______Lithologic Description_____ Section Base 8500 SI-309-01-75 Fine sand. light olive gray 9.1 (5Y5/2). Glauconite. Carbonized wood (rare). Noncalcareous. 8501 SI-309-02-75 Very fine sand, Light olive 39.6 yellow (5Y5/4). Glauconite. Noncalcareous. 8502 SI-309-03-75 Very fine sand, Dark yellowish 106.7 brown (10Y4/2). Glauconite and jarosite. Carbonized wood. Noncalcareous. 314 Section 18 Meters Above A B______Lithologic Description______Section Base 8503 SI-310-01-75 Very fine sand. Light olive gray 16.8 (5Y6/1) streaked with grayish yellow (5Y8/4). Glauconite and jarosite. Noncalcareous. 8504 SI-312-01-75 Fine sand. Light olive gray 59.4 (5Y5/2). Glauconite and jarosite. Carbonized wood, finely comminuted. Noncalcareous. 8505 SI-313-01-75 Medium to coarse sandstone. 67.5 Calcite cement. Olive gray (5Y4/1). Glauconite. Pelecypods. Carbonized wood (rare). Calcareous. 315 Section 19 Meters Above A B ______Lithologic Description______Section Base 8506 SI-319-01-75 Very fine sand. Yellowish gray 18.3 (5Y7/2). Glauconite and jarosite. Noncalcareous. 8507 SI-320-01-75 Very fine sand. Light olive gray 51.8 (5Y5/2). Glauconite and jarosite. Carbonized wood. Noncalcareous. 8508 SI-321-01-75 Silty fine to medium sand. Light 116.2 olive gray (5Y6/1). Glauconite and jarosite. Noncalcareous. 8509 SI-324-01-75 Fine to medium sand. Light olive 123.6 brown (5Y5/4). Glauconite and jarosite. Limonitic staining. Noncalcareous. 8510 SI-325-01-75 Very fine sandstone. Light 125.2 yellowish gray (5Y6/2). Calcite cement. Glauconite. Calcareous. 8511 SI-329-01-75 Fine sand. Olive gray (5Y4/1). 157.1 Glauconite. Calcareous. 316 Section 19 (continued) Meters Above A B______Lithologic Description__ Section Base 8512 SI-329-02-75 Medium, dirty sandstone. Calcite 157.2 cement. Olive gray (5Y4/1). Medium dark gray (N4). Calcareous. APPENDIX D - PIWOCYST DESCRIPTIVE MANUAL INTRODUCTION The use of dinocysts to solve geological problems assumes they can be repeatedly identified and classified according to some systematic scheme. Systematic classification is dependent upon morphographic anal ysis. Consequently, a thorough knowledge of dinocyst morphology must be cultivated from the beginning of dinocyst studies. The acquisition of such knowledge can be a laborious and time consuming task, especially so because information is scattered in an ever expanding body of litera ture. The purpose of this manual is to provide: 1) a logical and repetitive approach to the description of dino cysts by the use of a check-list; 2) a convenient record, written and illustrated, of each specimen studied; and 3) an expeditious approach to learning basic dinocyst morpholo gical terminology. The bases of this logical approach to describing dinocysts are a stand ardized morphological terminology and a set of descriptive sheets which emphasize uniformity in data collection. Each morphographic term occur ring on a descriptive sheet is defined in the illustrated glossary, which accounts for the bulk of this manual. 317 318 The glossary contrasts markedly with the invaluable glossaries of Wil liams et al (1973, 1978). In this glossary no attempt is made to incor porate from the literature the various interpretations of each term defined. Furthermore, only those terms necessary to provide a basic, concise description of most dinocysts are dealt with. The selection of a specific definition for a term is simply based upon what I believe is the most useful definition. Morphologic features that are unsuited to tabular treatment (e.g., gradational sculpturing) are entered on the last descriptive sheet under the section entitled "Comments". The descriptive sheets and the glossary can be used as a self- instruction manual because they emphasize the basic features that the palynologist is required to know in order to describe most dinocysts. DINOFLAGELLATES AND DINOCYSTS* Dinoflagellates are algae belonging to the Class Dinophycea of the Divi sion Pyrrophyta. Members of the Order Peridinales are the major group of modern dinoflagellates known to produce dinocysts during their life cycle. Because of this, most fossil dinocysts are attributed to the Order Peridinales. Dinoflagellates of the Order Peridinales possess a theca, or cell cov ering, composed of polygonal, cellulosic plates which are arranged in latitudinal series around the cell. The plates are designated by an alphanumeric nomenclatural system (Evitt, 1969) as indicated in text- figure 60. Adjacent plates of the theca usually overlap along tapering margins, where they are firmly, yet flexibly, attached to each other. The plates separate after the death of the cell or after encystment. The morphology of many dinocysts mimics that of the vegetative dinofla- gellate which produced them. Areas, or paraplates, reminiscent of thecal plates are often clearly evident. Most paraplates are not dis crete, structural units of the wall, as are thecal plates. Rather, paraplates are merely surficial features delimited by sculptural ele ments. The exceptions are the paraplates forming the operculum, which are released during archeopyle formation. The operculum is surrounded * The reader should refer to the glossary at the end of this manual for the definition of unfamiliar morphological terms encountered in this and the following discussions. 319 PLATE SERIES APICAL ANTERIOR INTERCALARY FRECINGULAR CINGULAR POSTCINGULAR SULCAL POSTERIOR INTERCALARY ANT APICAL Text-figure 60. Generalized dinoflagellate illustrating the alphanu* ■eric syabols, naaes, and relationships oi thecal plates.(Adapted froa 16.) 320 321 by sutures which provide for the total or partial separation of its constituent paraplates from the dinocyst wall. Like thecal plates, paraplates are designated by an alphanumeric nomenclatural system (text-figure 61). PARAPLATE SERIES APICAL ANTERIOR INTERCALARY PRECINGULAR PARACINGULAR POSTCINGULAR PARASULCAL ANTAPICAL Text-figure 61. Fossil dinocyst exhibiting psrsplste synbols, nines t and relationships. (Adapted froa 21.) 322 RECOGNITION OF DINOCYSTS Many organic-walled microfossils encountered in palynologic sample prep arations resemble dinocysts. In order to facilitate recognition of dinocysts, certain criteria were suggested by Evitt (1961), including: 1) total or partial subdivision of the dinocyst wall by sculpture or processes into paraplates suggestive of the plates observed on the dinoflagellate theca; 2 ) the presence of an archeopyle; 3) the presence of a paracingulum, parasulcus, apical and antap- ical horns and other basic elements comparable to features observed on the motile dinoflagellate theca; and 4) the presence of a basic bilateral symmetry. w Many dinocysts are readily recognized because their overall shape is very similar to that of a motile dinoflagellate theca. For example, the peridinoid outline is often characterized during both the encysted and motile stages by one anterior horn and two posterior horns; both stages may also exhibit longitudinal and equatorial grooves. Other dinocysts markedly differ from the shape of the motile theca and are more diffi cult to identify. The presence of an archeopyle often is the only evi dence for a specimen's dinocyst affinity. Palynological specimens resembling dinocysts, but lacking definitive dinocyst characteristics are placed in the Group Acritarcha. Evitt (1963) established this polyphyletic group as a holding category for organic walled microfossils of uncertain biologic affinities. 323 324 Acritarchs are composed of one or more wall layers surrounding a central cavity and exhibit a wide range of shape, symmetry, sculpture, and structure. Many are superficially similar to dinocysts and may even bear characteristic openings in the test. However, the split, rupture, or circular opening (i.e., a pylome) in the acritarch wall(s) differs markedly from the angular archeopyle opening characteristic of the dino cysts. The difference in the shape of these openings is one of the criteria for separating the two groups. Several genera formerly placed in the Acritarcha have been recognized as dinocysts and appropriately transferred to the Class Dinophyceae. Others remain to be evaluated but lack the definitive morphological fea tures to assure their identification as dinocysts using current palyno- logic concepts. DINOCYST ORIENTATION Orientation involves determining a set of conventional directions. Assignation of the terms used in orientation is made with reference to the dinocyst ambitus (i.e., outline in dorso-ventral view) as seen with the dorsal side uppermost (text-figures 62 and 63). The morphographic criteria used to orientate a dinocyst include: 1) The archeopyle. 2 ) The paracingulum. 3) The parasulcus. 4) The parasulcal notch. 5) Process distribution and differentiation. 6) Horn relationships. 7) Miscellaneous. Examples of dinocysts exhibiting these features are given in Plates 17 and 18. The Archeopyle A dinocyst may have an archeopyle on the dorsal surface of the epicyst (Plate 17, figures 1-3) or in a terminal position (Plate 17, fig ures 4-8). Some dinocysts apparently lack any type of archeopyle what soever (Plate 17, figure 9). If an archeopyle occurs in a terminal position, it may be on the ante rior end (i.e., an apical archeopyle, Plate 17, figures 4-6) or on the posterior end (i.e., an antapical archeopyle, Plate 17, figure 7). 325 ANTERIOR END APICAL HORN RMHEOPYLE EP1CYST LEFT RIGHT RIGHT LEF1 PARACINBULUN PARASULCUS HYPOCYST ANTAPICAL HORNS Dorsal Surface Ventral Surface POSTERIOR END Text-figure 62. Generalized dinocyst with a dorsal archeopyle illus trating the orientation terminology and some of the norphologic features applicable to peridinioid forms. 326 ANTERIOR END ARCHEOPYLE APICAL PARASULCAL NOTCH LEFt R1BHT RIGHT PARAMH6ULUH LEFT PARASULCUS Dorsal Surface Ventral Surface POSTERIOR ENO Text-figure 63. Generalized dinocyst with an apical archeopyle dep icting the orientation terminology applicable to this type of dinocyst. 328 Apical archeopyles constitute the vast majority of terminally located archeopyles. The archeopyle margin of an apical archeopyle is generally zigzag (Plate 17, figure 4) as dictated by the shape of the paraplate boundaries forming the archeopyle suture. This fact may be useful in deciding whether one is looking at a specimen bearing an apical archeo pyle or at a lateral view of a specimen with a precingular archeopyle. Precingular archeopyles never have a zig-zag margin (Plate 18, figures 1 and 2). The characteristic loss of one hemisphere during archeopyle formation seems to be restricted to the epicyst of the dinocyst. The operculum of the epicystal archeopyle detaches along the anterior border of the para- cingulum (Plate 17, figure 8). The only confirmed antapical archeopyles occur in species of the genus Tuberculodinium (Plate 17, figure 7). Such archeopyles may be formed by the loss of one or more paraplates. The Paracingulum The paracingulum is usually a continuous feature on the dorsal surface of the dinocyst (Plate 17, figures 1, 4, and 9), whereas it is inter rupted by the parasulcus on the ventral surface (Plate 17, figure 5; Plate 18, figure 3). The ends of the paracingulum are commonly offset in an anterior posterior direction. In such cases the left end of the paracingulum is always more anteriorly located than is the right end of the paracingulum (Plate 17, figure 5; Plate 18, figure 3). 329 The paracingulum may be expressed by a groove (Plate 18, figures 5 and 6), an unsculptured area (Plate 18, figure 5), or by distinctive processes or sculpturing (Plate 17, figures 1, 2, 5, 8, and 9). Some times the paracingulum is not evident at all (Plate 17, figures 3 and 6; Plate 18, figures 1, 2, and 8). The Parasulcus The parasulcus always occurs on the ventral surface. It is often restricted to the hypocyst (Plate 18, figure 5) but may extend on to the epicyst (Plate 17, figure 5; Plate 18, figures 3 and 6). The parasulcus may be indicated by a groove, differential sculpturing, distinctive processes (Plate 17, figure 5), or an area devoid of sculp turing (Plate 18, figure 5). Sometimes all indication of the parasulcus is absent. The Parasulcal Notch A parasulcal notch commonly occurs on dinocysts exhibiting an apical archeopyle. When present, it is located on the ventral surface at the anterior end of the parasulcus (Plate 17, figure 5; Plate 18, figure 6). This notch forms a re-entrant angle in the archeopyle margin where the parasulcal tongue (i.e., the first apical paraplate) was located prior to the loss of the operculum. 330 Process Distribution The distribution and differentiation of processes often can be used for the orientation of chorate dinocysts. Parasulcal and paracingular pro cesses are frequently different from all other processes in that they are thinner, joined in pairs, or uniquely structured (Plate 17, fig ures 2 and 5). Some chorate dinocysts display a distinctive process in the anterior, posterior, or both polar positions (Plate 17, figures 2, 3, and 5). Horn Relationships Dinocysts exhibiting more than one apical horn are not known, whereas the antapex may have zero, one, two or more horns (Plate 17, figures 4 and 6; Plate 18, figure 7). If a dinocyst has two antapical horns of unequal length, the longer horn is always the left horn (text-figure 3). Some dinocysts display postcingular as well as antapical horns. If only one postcingular horn is present (Plate 17, figure 4; Plate 18, figure 8), it is on the right side of the dinocyst. If two postcingular horns are present, the larger horn often is on the right (Plate 18, figure 4). Miscellaneous Features Used in Dinocyst Orientation The following general observations may be of assistance in orientation. 1) Smaller paraplates and/or processes often occur on the ventral sur face of the dinocyst. 331 2) Paraplates are generally larger on the hypocyst than on the epi- cyst. 3) The anterior end of the dinocyst is usually narrower than the pos terior end. 4) Paraplates on the epicyst are generally wider posteriorly than anteriorly. 5) Paraplates on the hypocyst are generally wider at their anterior end than at their posterior end. 6) Enlarged features usually occur on the posterior end of the dino cyst (e.g., protuberances or horns). Table 23 summarizes the major orientation criteria and lists the orien tation directions each criterion can be used to determine. 332 ORIENTATION ORIENTATION N0RPH0L061C LOCATION ON DIRECTIONS CRITERIA EXPRESSION DINOCYST DETERNINEO Proslnent zigzag ftpleal (the onig A n t e r i o r - ■ a r g ln continued antopical P o s t e r i o r . archeopgies are partlg zigzag too.) Approxleatetg on* Eplcgstoi Anterlor- MtCHEOPTLE holt dlnocgst P o s t e r l o r . ■ l o s i n g Opening on surface Anterior, dorsal A n t e r l o r - of dlnocgst s u r t o c e . Posterlorj Right-Left) Dorsal-ventral. Continuous feature Dorsal Surface Dorsal-Ventral. ( u s u a l i g ) Interrupted bg Ventral Surfacej Dorsal-ventral. PARAC1N6ULUN parasutcusj ends Left end 1s nore (Also right-left nog be off-set anterlorig located t A n t e r i o r - relotlue to eoch than right end. If Posterior If o t h e r . o f f s e t . o f f s e t . > LongItudlnoi ventral Surface) A n t e r l o r - feature which o f h g p o e g s t. Mag Posterlorj PARASOLCUS Interrupts the extend onto splcgst. Dorsal-Ventral) paroclngutun Right-Left. Re-entrant angle ventrol Surface) A n t e r i o r - In a p i c a l anterior end of P o s t e r l o r , PAAASULCAL archeopgi* narglnj parasulcus. Dorsal-ventral j NOTCH narks forner Right-Left. position of first aplcoi porapiot*. One horn onlg. Aplcoi horn A n t e r l o r - P o s t e r l o r . Two e q u a l h o r n s ftntoplcal horns. A n t e r l o r - at one end of P o s t e r l o r . d l n o c g s t . HORN Two unequal horns Antaplcal hornsi A n t e r i o r - at 6ne end of longer horn Is Posterior) RELATIONSHIPS d l n o c g s t . the left horn. Dorsal-ventral , Right-Left. One post-clngular Right post- A n t e r l o r - h o r n . clngular horn. Posterlorj Dorsal-Ventral; Rlght-Left. More than on* The longest horn A n t e r i o r - post-clngular horn. Is proboblg the Posterior) right post- Dorsal-Ventral , clngular horn. Right-Left. To m * 13. Iimiarv of the aojor orientation criteria and the orientation direction* which tlwu can be u * * a to detereln*. APPARENT MORPHOLOGICAL RELATIONSHIPS The morphographic features differ from one side of a dinocyst to the next. Apparent relationships between these features also vary, depending upon the specimen's attitude on the slide and upon whether the specimen's dorsal or ventral surface is being observed. These differ ences are illustrated in text-figure 64. A generalized peridinoid dinocyst, with its dorsal surface uppermost, is shown at two focal levels in text-figures 64a and 64b. When the upper surface of the dinocyst is in focus (text-figure 64a), the archeopyle and the uninterrupted trace of the paracingulum are evident. This is referred to as the dorsal view of the dorsal surface. If the microscope is then focused through the dinocyst to the lower surface, the para- sulcus and the interrupted paracingulum are seen. These features indi cate that the ventral surface is in focus (text-figure 64b). This is referred to as the dorsal view of the ventral surface. If the microscope is focused on the uppermost surface of a specimen and it is determined that it is the ventral surface in focus, the image is referred to as the ventral view of the ventral surface (text-figure 64c; note parasulcus and interrupted paracingulum). Focusing through the ventral surface to the dorsal surface will bring into focus the ventral view of the dorsal surface (text-figure 64d, note the archeopyle and the continuous paracingulum). 333 334 HIGH FOCUS Text-figure 64a. Dorsal Text-figure 64c. Ventral view of the dorsal view of the ventral surface. surface. LOW FOCUS Text-figure 64b. Dorsal Text-figure 64d. Ventral view of the ventral view of the dorsal surface. surface. Text-figure 64. Specimen orientation and depth of focus related to apparent and real morphologic relationships. 335 The relationships between the antapical horns and between the ends of the paracingulum should be studied (text-figure 64). The longest antap ical horn on a specimen with its dorsal side uppermost (text-figures 64a and 64b) is on the left. This is designated "the left antapical horn". (See also the discussion of "Horn Relationships".) However, when the ventral side of a specimen is uppermost (text-figures 64c and 64d), "the left antapical horn" is now on the apparent right side of the specimen. This is because the specimen in comparison with text-figures 64a and 64b has been turned over. The specimen's dorsal surface is now in the low ermost position and can only be seen by focusing completely through the ventral surface. The apparent relationship between the ends of the paracingulum differs depending on whether the ventral surface is the uppermost or lowermost specimen surface. When the dorsal surface is uppermost, the left para cingulum end is more anteriorly located than is the right paracingulum end (text-figure 64b). Conversely, when the ventral surface is upper most, the apparent right end (actual left end) of the paracingulum is more anteriorly located than is the apparent left end (actual right end; text-figure 64c). Again, this apparent relationship results from the specimen having been turned over. Dinocysts are commonly compressed, often in a direction perpendicular to the dorsal and ventral surfaces; the resulting juxtapositioning of these opposite surfaces can be confusing to the eye. The microscope must be focused up and down through the specimen until it is determined which surface is closest to the cover glass of the slide. 336 IT IS IMPORTANT TO REMEMBER TO DETERMINE WHICH SURFACE OF HIE SPECIMEN IS UPPERMOST AT THE OUTSET OF ORIENTATION PROCEDURES. PRACTICAL NOTES ON ORIENTATION The ease with which a particular specimen can be oriented depends upon its preservation, morphologic differentiation, and the attitude it assumes within the mounting medium. Not all dinocysts can be oriented. Some are just too fragmentary, distorted, biologically degraded, or thermally altered to permit orientation. However, such specimens often can yield useful information if enough well preserved specimens have been studied previously. This experience factor can be improved if one selects the best specimens for study in the beginning. Poorly preserved specimens can be studied later, if necessary. Not all dinocysts exhibit enough morphologic differentiation to allow complete orientation. Some may exhibit only an archeopyle, whereas others may have an archeopyle, paracingulum, parasulcus, and distinctive antapical horns. The wide variation in the presence of features appli cable to dinocyst orientation must be expected. Again, experience often can provide supplementary, species specific criteria for detailed orien tation. The position a dinocyst ultimately assumes on a slide depends upon the specimen's shape after sample preparation is completed. Spherical uncompressed specimens, for example, do not settle in any preferred orientation. It is not uncommon to find apical, antapical, right and left lateral, as well as dorsal and ventral orientations of such dino cysts on the same slide. 337 338 Elongated dinocysts, however, usually come to rest with their longest axis parallel to the surface of the slide, and either their dorsal or ventral surface uppermost. Only occasionally do they settle in another orientation. An Orientation Flow Chart Text-figure 65 illustrates a flow-chart of procedures that can be sequentially applied when orienting dinocysts. Although this is not completely applicable to every specimen, it provides an organized approach to orientation. 339 FOCUS ON UPPERMOST SURFACE DETERMINE HORN RELATIONSHIPS LESS THAN TWO HORNS OF TWO HORNS OF 2 HORNS ON EOUAL LENGTH UNEOUAL LENGTH EITHER END ON ONE END ON ONE END OF DINOCYST OF DINOCYST OF DINOCYST ASSIGN ANTERIOR-POSTERIOR ASSIGN ALL ORIENTATION ORIENTRTION CONVENTIONS CONVENTIONS DETERMINE ARCHEOPYLE TYPE ABSENT DORSAL TERMINAL ARCHEOPYLE ARCHEOPYLE ASSIGN ALL ORIENTATION OBSERVE CONVENTIONS PARACINGULUM ASSIGN ALL ORIENTATION CONVENTIONS T«xt-figur* 6 5 . Orltniotlon flow chart for dtnocysts. HOW TO USE THE DESCRIPTIVE SHEETS The following procedure is suggested for using the descriptive sheets. Record the pertinent sample data (geographic location, sample, and slide number, etc.) at the top of the sheet. Next, take the time to make an accurate drawing of the dinocyst. Drawing forces one to see rather than merely look at the specimen under investigation. After the drawing is complete, consider each group of morphological fea tures in turn, beginning at the top of the left hand column on descrip tive sheet #1. Inspect the specimen to determine which morphologic term applies, place the appropriate number in the box, and move to the next lower group of features in the column. Repeat the procedure group by group and column by column. For example, the first group of features in column one, page one of the descriptive sheets is titled Ma.jor Dinocyst Type. If the specimen is determined to be a chorate dinocyst, place the number 2 in the box pro vided. Proceed to the second group, entitled Cavate Dinocyst Type. Since the example specimen being studied is a chorate dinocyst, and not a cavate dinocyst, proceed to the next group, entitled Chorate Dinocyst Type. Determine which type of chorate dinocyst the specimen represents and place the correct number in the appropriate box. 340 3 hi Some morphologic term groups provide space to register data pertaining to the various wall layers which may be encountered on dinocysts. For example, under the heading, "Dinocyst Shape1*» are three pairs of boxes, above which are written the prefixes "peri-", "meso-", and "endo-". These prefixes refer back to the group heading and are read as "Pericyst shape", "Mesocyst shape", and "Endocyst shape". The shape of the peri cyst, mesocyst, and endocyst are determined and the appropriate number is written in the appropriate box. The box arrangements for primary and secondary morphologic features are used in the same way as the prefix boxes (e.g., see the morphologic term group "POSITIVE SCULPTURE" on descriptive Bheet 3). An exception to the above procedures are boxes where the number of observed morphological features are to be entered (e.g., Observed Para- plates). In these boxes, merely record the number of items observed. The last page of the descriptive sheet provides space for comments on morphologic features not covered in the descriptive scheme. For example, observations concerning gradational morphologic features can be placed here to amend the tabular data. GLOSSARY OF SELECTED MORPHOLOGICAL TERMS INTRODUCTION The glossary contains a definition of each morphologic term listed on the descriptive sheets. Most terms are followed by the name of the mor phologic group to which they belong. This bracketed name correlates with the descriptive sheet morphologic group heading under which the term being defined is found. For example: BIFURCATE PROCESS TIP (Process Tips): "BIFURCATE PROCESS TIP” is the term being defined. "Process Tips" is the morphological group heading under which it is listed on the descrip tive sheets. This feature is a cross index between the Glossary and the descriptive sheets. Some defined terms are not followed by a morpholo gical group heading because they are general terms which do not occur within a specific morphological group. The definitions are accompanied by an illustration which is new or has been redrawn from a preexisting publication. Following each definition is a bracketed number, [e.g., (23)], referring to the source of the illustration. The numbers coincide with those in the reference list at the end of the glossary. 342 343 Some definitions are followed by a bracketed taxonomic name and a number (e.g., Deflandrea sp.; 25). The name is that of the illustrated dino cyst and the taxonomy used herein follows that of the author from whose publication the illustrations were derived. No attempt has been made to reassign the dinocyst examples to comply with current taxonomic thought. The number refers to the original source as cited in the reference list. The figures illustrate morphologic features and are not intended for taxonomic use. THE GLOSSARY 344 345 ACCESSORY PARASUTURES (Additional Archeopyle Features): Secondary parasutures, splits or minor clefts adjacent to the main archeopyle par- asutures are accessory parasutures. Such parasutures may occur on the operculum or may project toward the paracingulum on the dinocyst body. They develop on paraplate boun daries, even where tabulation is not x / obvious. (15). ACICULAR PROCESS (Process Type): A slender process having a needle-like shape (e.g., Hystrichodinium pul- chruro; 4, 7). ACULEATE PROCESS TIP (Process Tips): A hollow process tip which is flared back at approximately right angles to the process axis and whose distal margin is composed of pointed serra tions. (e.g., Hystrichosphaeridium tubiferum; 10, 6). ACUMINATE PROCESS TIP (Process Tips): A closed or solid process tip which is distally pointed (e.g., Ooerculodinium hirsutum; 10, 8). 346 ALTISEPTATE DINOCYST (Chorate Dino cyst Type): A chorate dinocyst possessing high septa, crests, or nembranes, of a height greater than four-tenths the overall radius, and projecting perpendicularly from the wall of the dinocyst. Such projec tions often delimit paraplate boun daries. Altiseptate dinocysts do not have processes such as are pre sent on skolochorate dinocysts, (e.g., Heslertonia heslertonesis; 27). ANNULATE COMPLEX (Process Complex Type): A closed, circular distribu- tion of processes. The processes may or may not be jointed to one another at any point along their length (e.g., Systematophora valensii; 36, 29). ANTAPICAL ARCHEOPYLE (Archeopyle Type): An archeopyle formed by a partial or total loss of one or more antapical paraplates (e.g., Tubercu- lodinium sp.; 36). ANTAPICAL HORN (Horns Present): A posterior projection or protuberance of the hypocyst expressed as one or two horns, of equal or unequal lengths (e.g., Deflandrea cf. D. diebeli: 16). ANTAPICAL PARAPLATES (Observed Para- plates): The most posteriorly located of all paraplates bordered on their anterior margin by the postcingular and/or posterior inter* calary paraplates. They correspond in position to the antapical plate of the motile dinoflagellate theca. (21). ANTERIOR INTERCALARY PARAPLATES (Observed Paraplates): Paraplates that are bordered on their anterior margin by the apical paraplates and on their posterior margin by the precingular paraplates. They corre* spond in position to the anterior intercalary plates of the motile dinoflagellate theca. (21). ANTERIORLY ATTACHED OPERCULUM (Status of Operculum): An operculum which characteristically, rather than accidentally, remains attached to the dinocyst along the anterior margin of the archeopyle (e.g., Rhombodinium ? pentagonum; 35). APICAL ARCHEOPYLE (Archeopyle Type): An archeopyle formed by the partial or total loss of paraplates from the apical series alone or with preap- ical and/or minor anterior interca lary paraplates. (15). APICAL HORN (Horns Present): The anterior projection or protuberance of the epicyst (e.g., Deflandrea sp.; 16). APICAL PARAPLATES (Observed Para plates): The most anterior series of paraplates or those bordered on their anterior margin by the preap- ical paraplate series. Their poste rior margins abut the precingular paraplates and/or anterior interca lary paraplates. These paraplates correspond in position to the apical plates of the motile dinoflagellate theca. (21). ARCHEOPYLE: The aperture in a dino- cyst through which the dinoflagel late exits during excystment (e.g., Cordosphaeridium filosuro; (42). (See ANTAPICAL, APICAL, EPICYSTAL, INTERCALARY, PRECINGULAR, AND TRANSAPICAL SUTURE ARCHEOPYLE.) ARCHEOPYLE FORMULA: A series of alphanumeric symbols used to desig nate the number, type and interrela tionship of the paraplates which comprise the operculum of a dino cyst. (A detailed discussion of archeopyles and archeopyle formula tion is beyond the scope of this manual. See Evitt (1967) and Lentin and Williams (1976) for coverage of this topic.) ARCUATE COMPLEX (Process Complex Type): A series of processes arranged in an arc. The processes may or may not be joined to one another at any point along their length. (36). AREOLATE SCULPTURE (Positive Sculp ture): A regular irregular polyg onal mesh of low ridges, forming a reticulum. (AO). ARRGUICAVATE DINOCYST (Cavate Dino- cyst Type): Cavate dinocysts whose walls are separated from each other by rectilinear folds, which form tunnel-like spaces between the wall (e.g., Carpodinium granulatum: 4). ATTACHED OPERCULUM (Status of Oper culum) : Opercula which characteris tically remain attached to the cysts, (e.g., Forma P; 15). 351 ATTENUATED HEXA 2A ARCHEOPYLE (Type of 2A Archeopyle): An intercalary archeopyle in which the H2 and H6 margins of the 2a paraplate are exceptionally long and the H3 and H5 margins are exceedingly short. The HI margin is shorter than the H4 margin and both are shorter than the H3 and H5 margins. (See HEXA 2a ARCHEOPYLE. Palaeocystodinium sp.; 23, 16.) AUTOCOEL (Cavities Present): The cavity formed by the autophragm in AUTOCOEL single-walled dinocysts. (36). AUTOCYST (Dinocyst Structure): A dinocyst composed of only one wall (i.e., the autophragm) is referred AUTOCYST — to as an autocyst (e.g., Leieunia sp.; 36). AUTOPHRAGM (Phragma): The wall of a dinocyst exhibiting only a single wall, rather than multiple walls (i.e., periphragm, endophragm). Autophragm also describes the main wall of a dinocyst which exhibits an ectophragm, but no additional walls within the autocyst. (36). BACULATE SCULPTURE (Positive Sculp ture): A type of positive sculpture characterized by a bluntly termi nated, cylindrical projection in which the diameter is less than the height. (40). BICAVATE DINOCYST (Cavate Dinocyst Type): Cavate dinocysts in which the walls are separated anteriorly and posteriorly and appressed equa torial ly. Vail separations are not limited to the apace within peri- phragm projective structures (such as horns) or between the base of such projective structures and the next inner wall (e.g., Chatangiella tripartita: 23). BICONICAL (Dinocyst Shape): A form which resembles two cones with their bases abutting each other. The longitudinal axis is longer than the equatorial axes (e.g., Dinogymnium acuminatum; 17). BIFID PROCESS TIP (Process Tips): A process tip whose distal end is split into two equals parts by a fissure. The separated parts are less separated and shorter than those observed on a bifurcated pro cess tip (e.g., Cleistosphaerldium multifurcatum; 10, 8). BIFURCATE PROCESS TIP (Process Tips): A process tip which is split distally into two sections of equal or unequal length. BRANCHED PROCESS (Process Type): A process which splits into two or more branches at one or more places along its length (e.g., Perisseias- phaeridium pannosum; 6). BROAD HEXA 2A ARCHEOPYLE (Type of 2A' Archeopyle): A 2a archeopyle exhibiting very long HI and HA mar gins, medium length H2 and H6 mar gins, and exceedingly short H3 and H5 margins (see HEXA 2A ARCHEOPYLE; e.g., Deflandrea boloniensis; 23). BUCCINATE PROCESS (Process Type): A cylindrical process which flares widely at its distal end: trumpet- shaped (e.g., Hystrichosphaeridium tubiferum: 10, 14). BULBOSE PROCESS (Process Type): A process whose largest diameter is at Its proximal end. The process con tracts rather sharply and then flares distally to a diameter somewhat less than that of its prox imal diameter: flask- or bottle shaped. (10). CAMOCAVATE DINOCYST (Cavate Dinocyst Type): The wall separation between the endocyst and the pericyst is strongly asymmetrical with respect to the longitudinal axis and/or the dorsal-ventral axis, (e.g., Thalas- siphora sp.; 19). CAPITATE PROCESS TIP (Process Tips): A process that has a globular or an expanded tip (e.g., Splndinium mac- murdoense). CARDIOFORM (Dinocyst Shape): Broadly heart-shaped when viewed dorso-ventrally and reniform in apical-antapical view. The apical- antapical axis is longer than the dorsal-ventral axis. (34). CAULIFLORATE PROCESS TIP (Process Tips): A process tip whose shape is botryoidal. (10). CAVATE DINOCYST (Major Dinocyst Type): A dinocyst composed of two or three walls (i.e. periphragm and endophragm, or periphragm, meso- phragm and endophragm). Each wall is separated from the next inner wall by a cavity (i.e. pericoel, mesocoel, or endocoel; Deflandrea sp; 36). CBRATIOID (Dinocyst Shape): An out line similar to the dinoflagellate Ceratium, i.e. a dinocyst having one long apical horn, one or two oppo site post-paracingular and one, rarely two, antapical horns sepa rated by a broad equatorial area. The antapical horn arises from and projects more posteriorly than does the post-paracingular horn (e.g., Muderongia staurota; 32). CHORATE DINOCYST (Major Dinocyst Type): A dinocyst characterized by various, relatively long sculptural features whose relationship to the dinocyst diameter is expressed as the ratio: 356 (Radius of endocoel)/(Radius overall). The ratio varies between 0.5 and 0.6 in chorate dinocysts. The sculptural features are generally processes, ridges, or septa, (e.g., Tanvosphaeridium sp. and Exocos- phaeridium pseudohystrichodinium; 16. 8). CIRCUMCAVATE DINOCYST (Cavate Dino cyst Type): Cavate dinocysts in which the walls are appressed in the mid-dorsal and mid-ventral areas when seen in dorsal-ventral view, whereas the walls are separated in the marginal areas (e.g., Sirmiodl- niuro grossi; 1). CLAVATE PROCESS TIP (Process Tips): A process tip characterized by a rounded, bulging termination which Is larger in diameter than the prox imal end of the process. (10). 357 CLAVATE SCULPTURE (Positive Sculp ture): Positive sculpture charac terized by club-shaped projections whose diameter is least proximally 2 and greatest distally. The height of the projections is greater than the maximum diameter. (AO). COMBINATION ARCHEOPYLE (Archeopyle Complexity): An archeopyle formed by the separation or partial separa tion along parasutures of an oper culum composed of two or more para- plates from different paraplate series. (15). COMPOUND ARCHEOPYLE (Archeopyle Com plexity): An archeopyle formed by the separation or partial separation along sutures of an operculum com posed of two or more paraplates from the same paraplate series (e.g., Pareodinia dasvforma; 16). COMPRESSED BICONICAL (Dinocyst Shape): A biconical dinocyst in which the dorsal-ventral axis is shorter than the transverse axis. (34). 358 COMPRESSED CERATIOID (Dinocyst Shape): A form with a rounded, dome-shaped anterior region, a bilo- bate posterior region, and an ellip tical cross section. The antapical lobe or horn arises and projects more posteriorly than the shorter postcingular lobe or horn. (34). COMPRESSED PERIDINIOID (Dinocyst Shape): A form whose outline varies from oval to pentagonal and usually exhibits an apical horn, two lateral horns (may be absent), and one or two antapical horns. The dorsal- ventral axis is shorter than either the apical-antapical or the tran sverse axes. (34). CONICAL PROCESS (Process Type): A process with a relatively large basal diameter which decreases dis tal ly in a marked and continuous manner. The distal termination is pointed (e.g., Dioxya armata: 3, 10). CORNUCAVATE DINOCYST (Cavate Dino cyst Type): A cavate dinocyst in which the walls are only separated at or near the base of horns or pro trusions (e.g., Palaeocystodinium •p.; 16) CYLINDRICAL PROCESS (Process Type): A process whose diameter is constant throughout its length (e.g., Hystri- chosphaeridium ? arundum; 10, 25). DENTICULATE PROCESS TIP (Process Tips): A tubular process tip whose distal end is regularly serrated. The resulting uniform projections are parallel to the process axis and point outward from the dinocyst (e.g.Hvstrichospaeridium tubiferum; 10, 6). DEXTROROTATORY PARACINGULUM (Para- cingulum Type): A paracingulum whose two ends are displaced antero- posteriorly adjacent to the para- sulcul area. When Been in the dorsal-ventral view (ventral surface uppermost), the left end is more anteriorly located than the right end. (40). DIGITATE PROCESS TIP (Process Tips): A solid process tip split distally or at a number of levels along its length into finger-like branches. (10). PIRIGATE PROCESS TIP (Process Tips): A tubular process tip exhibiting aculeae which project perpendicu larly to the surface to the dino cyst. (10). 361 DISTAL PLATFORM (Process Tips): A process tip whose distal end expands into a flat, undulating or funnel- ss shaped circular to polygonal area, often fenestrate. (e.g., Areos- phaeridimn diktyplokus; 12). ECHIKATE SCULPTURE (Positive Sculp ture) : Positive sculpture typified by tapering, possibly long, and gen erally sharp-pointed spines. (40). ECT0C0EL (Cavities Present): A cavity formed between the ectophragm ECT0C0EL and the outermost major wall (i.e. the periphragm in multi-walled dinocysts and the autophragm in single-walled dinocysts; e.g., tfet- zeliella coleothrypta; 18). ECTOPHRAGM (Phragma): A thin, con tinuous or discontinuous membrane, trabeculae or ribbon-like structure supported on the distal ends of pro cesses or projections originating from the underlying wall (i.e. the ECTOPHRAGM periphragm or autophragm), or per haps by inward projecting continua tions of the ectophragm (e.g., Vet- seliella coleothypta; 18). 362 ELLIPSOIDAL (Dinocyst Shape): Elliptical in the dorsal-ventral view and elliptical or rounded in the apical-antapical view. The apical-antapical axis is longer than the equatorial axes. (34). ELONGATE (Dinocyst Shape): The longitudinal axis is much longer than its equatorial axes and the overall shape is ellipsoidal to fusiform (e.g., Pa1aeocystodinium golzowense; 1). ENDOARCHEOPYLE (Archeopyle(s) Pre sent): An archeopyle formed in the endophragm of multi-walled dinocysts by the complete or partial release of an operculum from the endocyst (e.g., Deflandrea (s.l.); 18). ENDOCOEL (Cavities Present): The central cavity formed or delimited in multi-walled dinocysts by the endophragm. The innermost cavity formed in multi-walled, multi-cavity dinocysts, (e.g., Rhombodinium glabrum; 36). ENDOCYST (Dinocyst Structure): The three-dimensional body formed by the endophragm. (e.g., Rhombodinium glabrum; 36). ENDOPHRAGM (Phragma): The innermost wall of a multi-walled dinocyst. It may be separated or closely appressed to the wall layer sur rounding it (either the mesophragm or periphragm). Support structures for the surrounding walls are rarely developed and when present are not regular structures, (e.g., Rhombo dinium glabrum; 36). ENLARGED ARCHEOPYLE (Additional Archeopyle Features): An archeopyle formed by the loss of an operculum composed of one or more complete paraplates plus portions of the sur rounding paraplates. Thus, the operculum is not bounded by para plate parasutures but by opercular sutures which cut through the adja cent paraplates or dinocyst wall adjacent to the opercular para- plated). (Modified from 40.) 364 ENTIRE PROCESS TIP (Process Tips): A tubular process tip which lacks outgrowths or perforations and whose •verted distal margin is not ser rated or otherwise uneven and ragged. EPICAVATE DINOCYST (Cavate Dinocyst Type): Cavate dinocysts in which walls are only separated anteriorly, and not merely in the basal area of or within an apical horn or protru sion (e.g., Nelsoniella tuberculata; 23). EPICYST (Parasulcus): That portion of the dinocyst anterior to the paracingulum. (21). EPICYST EPICYSTAL ARCHEOPYLE (Archeopyle Type): An archeopyle formed by the complete or partial separation of ell the paraplates anterior to the paracingulum. (15). EVEXATE PROCESS TIP (Process Tips): The distal diameter is smaller than the diameter of the process base and lacks any sort of distal knob, sharp point, or expansion. (10). EXCELLENT (Preservation): See PRESERVATION. FAIR (Preservation): See PRESERVATION. FENESTRATE PROCESS TIP (Process Tips): A tubular process tip whose walls are perforated to varying degrees by holes. The shape, size, and number of the holes is highly variable. (4). FLARED PROCESS (Process 7VPe): A type of hollow process, with or without an open distal end, whose diameter continuously increases from a relatively narrow base to a rela tive wide distal end. (10). FOLIATE PROCESS TIP (Process Tips): A process tip characterized by num erous short, truncated, or bifid members, which form a distal club like termination (e.g., Hvstrichok- olpoma rigaudae; 9, 10). FOSSAE PARASUTURES (Expression of Parasutures): The incised boun daries or inverse paraplate parasu tures between paraplates, which result in raised paraplate areas, (e.g., Eisenackia crassitabulata; 9). FOSSULATE SCULPTURE (Negative Sculp ture): Non-anastomising, elongate depressions or grooves. (40). FOVEOLATE SCULPTURE (Negative Sculp ture): Pits whose diameters are often greater than the length of the raised inter-pit areas. (40). 367 FREE OPERCULUM (Status of Oper culum) : An operculum which is com pletely detached from the remainder of the dinocyst. (15). GEMMATE SCULPTURE (Positive Sculp ture) : A type of positive sculpture characterized by grains or granules whose basal diameter is constricted and less than their height. (40). GONAL (Process Distribution): Pro cesses which arise at the intersec tion of three or more paraplate boundaries (e.g., Spiniferites sp.; 16). GOOD (Preservation): See PRESERVATION. GRANULATE SCULPTURE (Positive Sculp ture): A type of positive sculpture characterized by grains or granules whose basal diameter does not exceed their height. (40). GRANULES (Expression of Parasu- tures): Small, rounded lumps or nodes whose width does not exceed their height. Granules may deli neate paratabulation on the dino- cyst. (16). GYMNOCAVATE DINOCYST (Cavate Dino cyst Type): A cavate dinocyst in which the walls are separated only on latero-ventral surfaces. The apical-antapical view exhibits an outline similar to a side view of a bisaccate pollen with pendant sacci (e.g., Palynodinium grallator; 20). 369 HEXA 2A ARCHEOPYLE (Type of 2A Archeopyle): An archeopyle formed by the loss of a six-sided, second anterior intercalary paraplate (2a). The dimensions and proportions of the hexa 2a paraplate margins vary and are numbered from HI to H6 for identification. With the dorsal side of the dinocyst uppermost, num bering commences from the top margin (HI) of the 2a paraplate and pro ceeds in a counterclockwise direc tion around to the upper right margin (H6). Generally, four sides of the 2a paraplate are longer than the other two sides and the relative distribution of long and short sides results in the differentiation of four types of 2a archeopyles: (1) the standard hexa, (2) the attenuated hexa, (3) the broad hexa; and (4) the omegaform hexa. (23). HOLOCAVATE DINOCYST (Cavate Dinocyst Type): Cavate dinocysts composed of completely separated walls with sup porting structure between the more or less concentric walls. The amount of wall separation is more or less constant and is seen in all orientations, (e.g., Chlamydopho- rella ? membranoidea; 33) HYPOCYST (Parasulcus): That portion of dinocyst posterior to the para cingulum. (21). HYPOCYST --- INFUNDIBULAR PROCESS (Process Type) A process which is funnel-shaped, being widest and generally open dis tally (e.g. 10). INTERCALARY ARCHEOPYLE (Archeopyle Type): An archeopyle whose oper culum is composed of anterior inter calary paraplates. The operculum may be simple or compound. (15). INTERGONAL (Process Distribution): Processes located between two para plates, but not at the intersection of paraplate corners. (16). INTRATABULAR (Process Distribution) Processes or sculptural features located in the central portion of paraplates are said to be intrata- bular in position. Such features are usually surrounded by an unsculptured area or an area exhi biting a different type of sculp turing (e.g., Cordosphaeridium can- thanellum; 19, 32). LAEVOROTATORY PARACINGULUM (Para cingulum Type): A spiraled para cingulum whose right end is more anteriorly located than the left end, when viewed with the ventral surface uppermost (e.g., Psaligo- nvaulax deflandrei; 30). LAGENATE PROCESS (Process Type): A process whose relatively large basal diameter decreases sharply to a smaller diameter at its distal end. There is no distal flange caused by flaring as is the case on bulbose processes (e.g., Hystrichokolpoma cinctum; 10, 16). LATISPINOUS PROCESS (Process Type): A process elliptical in cross sec tion, with an open or distally closed termination, and a height less than its longest transverse dimension. (43). LENTICULAR (Dinocyst Shape): A form which is circular to broadly ellip tical, when seen in a dorsal-ventral view, and elliptical, though com pressed, in an apical-antapical view. The dorsal-ventral axis is much shorter than the other axes. (34). LINEAR COMPLEX (Process Complex Type): A straight*line distribution of processes which may or may not be joined to one another at any point along their length. (36). MARGINATE DINOCYST (Chorate Dinocyst Type): Dinocysts on which surface structures, such as processes and process complexes, are restricted to lateral paraplates, resulting in the ventral and dorsal paraplate areas being devoid of such structures (e.g., Areoligera cf. A. senonensis; 13). MEMBRANATE DINOCYST (Chorate Dino- cyst Type): A chorate dinocyst in which the processes are distally enclosed by an ectophragm (e.g., Membranilanacia reticulata: 39). MESOARCHEOPYLE (Archeopyle(s) Pre sent): An archeopyle formed in multi-walled dinocysts by the com plete or partial release of an oper culum from the mesophragm. 373 MESOCOEL (Cavities Present); The cavity, or cavities, formed in triple-walled dinocysts by the sepa ration of the endophragm and the aesophragm. Thus, the mesocoel is located between the pericoel(s) and MESOCOEL the endocoel and it is separated from them by the mesophragm and the endophragm, respectively (e.g., Deflandrea sp.; 36). HESOCYST HESOCYST (Dinocyst Structure); The three-dimensional body formed by the mesophragm (e.g., Deflandrea sp.; 36). MESOPHRAGM (Phragma): The middle wall in dinocysts having three walls; located between the peri MESOPHRAGM phragm and the endophragm. The mesophragm neither bears, nor is it supported by, structures or sculp turing (e.g., Deflandrea sp.; 36). NEGATIVE SCULPTURE (Type of Sculp ture): Sculpture in which the width of the raised sculptural elements (w-1) is greater than the distance between their bases (w-2). NON-REGULAR STRUCTURE (Structures Present): Structures (commonly pro cesses) which vary in number, shape, and distribution from one specimen to the next of the same species and are not considered to be basic char acteristics of a species, (e.g., Triblastula sp. and Thalassiphora sp.; 18). 374 NONTABULAR (Process Distribution): /jt / Sculptural features or processes g* A ^ A which are uniformly distributed, to a greater or lesser degree, and bear ^ A A A no relationship to the paratabula- / A A A A tion. They are generally numerous --- -A*— -n.- and closely spaced. (16). ^ /' A ^ OBLATE PROCESS TIP (Process Tips): A process tip which is cleanly trun cated at its distal end. (10). OHEGAFORM HEXA 2A ARCHEOPYLE (Type of 2A Archeopyle): Hexa 2a archeo- pyles having short H2 and H6 mar gins, and considerably longer H3 and H5 paraplate margins. The HI margin is longer than the H4 margin and both exhibit lengths midway between the longest and shortest paraplate margins (see HEXA 2A ARCHEOPYLE; e.g., Deflandrea (s.l.); 16, 23). OPERCULUM: An area composed of one or more paraplates which is released > from the dinocyst during excystment. The shape of the operculum is governed by its bounding parasu- tures. (15, 13). ORTHOGONAL PROCESS TIP (Process Tips): A hollow process tip with distal spines which project from the process approximately parallel to the surface of the dinocyst (e.g., Oligosphaeridimn complex; 10, 6). PANDASUTURAL (Distribution of Sculp ture) : Sculptural features which occur on the peripheral area of a paraplate. Often differs from that covering the remainder of the para plate (e.g., Deflandrea phosphori- tica; 18). PANDASUTURAL STRIAE (Expression of Parasutures): Transversely oriented striae confined to pandasutural areas between adjacent paraplates (e.g., Palaeoperdinium sp.; 16). PAPILLATE SCULPTURE (Positive Sculp ture): A type of positive sculpture composed of very low papillae or nipple-like projections. (40). 376 PARACINGULUM: Any morphologic fea ture (s) on the dinocyst which corre sponds to the cingulum or girdle on the dinoflagellate theca (e.g., Deflandrea sverdrupiana. Hvstrichok- olpoma eisenacki: 24, 37). PARACINGULAR HORN (Horns Present): A horn which projects from the lateral margin of the paracingulum (e.g., Wetzeliella articulate; 16). PARACINGULAR PARAPLATES (Observed Paraplates): The paraplates which comprise the paracingulum. Such paraplates correspond to the girdle or cingular plates on the motile dinoflagellate theca. (21). PARAPLATE: An area on the dinocyst, delimited by various morphologic features, which corresponds to a thecal plate (e.g., Paleoperldinium sp., Areoligera cf. A. senonensis; 18, 13). PARASULCAL NOTCH (Additional Archeo pyle Features): The re-entrant angle as seen in the outline of an apical archeopyle on the ventral surface of the dinocyst. The notch extends the archeopyle toward the paracingulum and represents the position formally occupied by the first apical (l1) paraplate. The sulcal notch points directly to the parasulcus (e.g., Forma A; 13). PARASULCAL PARAPLATES (Observed Paraplates): Paraplates which occupy the parasulcus. Such para plates correspond in position to sulcal plates of the motile dinofla gellate theca (e.g., Palaeoperidl- nium pyrophorum: 21). PARASULCAL TONGUE (Additional .Arche opyle Features): The extension of the apical archeopyle operculum, which formerly filled the area of the parasulcal notch. It is formed by the first apical paraplate (1*). (15). PARASULCUS: Any morphologic fea ture (s) on the ventral surface of the dinocyst which corresponds to the sulcus of the motile dinoflagel late theca. The parasulcus may be restricted to the hypocyst or may extend up onto the epicyst (e.g., Forma A, Deflandrea sp.; 13, 17). PARASUTURAL (Process Distribution): Sculpture or processes occurring along paraplate boundaries. Parasu- tural sculpture is usually linear and expressed by ridges, septa, channels, etc. (e.g., Spinferites sp.; 16). PARASUTURE: Morphologic features on the dinocyst which correspond to the plate sutures on the motile dinofla gellate theca (e.g., Gonyaulacysta 1unassica, Dichadogonyaulax schizob- lata; 13, 32). PARATABULATION: Hie complete set of paraplates delimited by parasutures or indicated by process distribution on the dinocyst. Paratabulation is analogous to tabulation on the motile dinocyst. Paratabulation is Indicated by an alphanumeric for mula. For example, that of Oligos- phaeridium complex (White) is Opr, 4' Oa, Oc, 5"', Op, I1'", Is. ( 6). PATULATE PROCESS TIP (Process Tips): A tubular process tip with aculeae which splay outward from their prox imal end, being neither perpendi cular nor parallel to the surface of the dinocyst. (10). PENITABULAR (Distribution of Sculp ture; Process Distribution): Sculp ture or processes adjacent to para plate margins. Such sculpture is usually linear and expressed as ridges, septae or membranes. (16). PENTAGONAL (Dinocyst Shape): A dinocyst whose overall shape is five-sided (e.g., Glyphanodinium faceturn: 11). 380 PERIARCHEOPYLE (Archeopyle(s) Pre sent): An archeopyle formed in multi-walled dinocysts by the com plete or partial release of an oper culum from the periphragm (e.g., Rhombodinium glabrum; 36). PERIARCHEOPYLE PERICOEL (Cavities Present): The outermost cavity, or cavities, formed in multi-walled dinocysts by PERICOEL- the separation between the peri phragm and the next inner wall (e.g., Rhombodinium glabrum; 36). PERICYST PERICYST (Dinocyst Structure): The three-dimensional body formed by the periphragm (e.g., Rhombodinium glabrum; 36). PERIPHRAGM (Phragma): The outer most, major wall present in multi walled dinocysts, exclusive of any PERIPHRAGM localized membrane, ectophragm, or trabeculae (e.g., Rhombodinium glabrum; 36). PHRAGMA: The general term for a dinocyst wall. ' Some dinocysts are composed of only one wall (i.e., an autophragm) whereas others have up to three walls. The different walls are the endophragm, mesophragm and periphragm (e.g., Deflandrea sp.; 36). PILATE SCULPTURE (Positive Sculp ture): A type of positive sculpture characterized by short projections which are swollen distally. Their overall configuration is suggestive of a blunt drumstick. (40). POOR (Preservation): See PRESERVATION. POSITIVE SCULPTURE (Type of Sculp ture) : Sculpture in which the width of the raised sculptural features (W-l) is less than the distance between sculptural features (W-2) on the surface of the phragma is posi tive. POSTCINGULAR HORN (Horns Present): A horn originating on the hypocyst just posterior to the paracingulum (e.g., Odontochitina; specimen pro vided by Evan J. Kidson). POSTCINGULAR PARAPLATES (Observed Paraplates): Postcingular para- plates are bordered on their ante rior margin by the paracingulum and on their posterior margin by antap- ical and/or posterior intercalary paraplates. They correspond to the postcingular plates of the motile dinoflagellate theca. (21). POSTERIOR INTERCALARY PARAPLATES (Observed Paraplates): Paraplates which are bordered on their anterior margin by the postcingular para plates and on their posterior margin by antapical paraplates. They cor respond in position to the posterior intercalary plates on the motile dinoflagellate theca. (30). POSTERIORLY ATTACHED OPERCULUM (Status of Operculum): An operculum which characteristically remains attached to the dinocyst along the posterior margin of the archeopyle (e.g., Spinidinium macmurdoense). PREAPICAL PARAPLATES (Observed Para plates): Paraplates that are located just anteriorly to the apical paraplate series (e.g., Gon- yaulacvsta jurassica; 33). PRECINGULAR ARCHEOPYLE (Archeopyle Type): Archeopyles are formed by the release of an operculum composed of precingular paraplates. The archeopyle may be simple or com pound. For example, Sillcisphaera ferox exhibits a simple precingular archeopyle, whereas Trioperculodi- nium siculum is a dinocyst bearing a compound archeopyle. The former is shown in a left lateral view. (16). PRECINGULAR PARAPLATES (Observed Paraplates): Paraplates located between the paracingulum, and the apical and intercalary paraplate aeries. (21). 384 PRESERVATION: An ordinal scale using the following definitions is utilized: Excellent - Specimen is complete in all details and displays no chemical or biological degradation. Good - Specimen exhibits minor phys ical damage and possibly some biolo gical and/or chemical degradation and/or thermal alteration. Fair - Specimen exhibits consider able physical damage and wall sec tions other than the operculum are missing. Biological and/or chemical degradation and/or thermal altera tion may be quite evident. Poor - Specimen is extremely broken, deformed and sections other than the operculum are missing. Biological and/or chemical degradation and/or thermal alteration has (have) pro gressed to an advanced state. PROCESS (Expression of Parasutures): An elongated projection arising from the surface of a dinocyst. Pro cesses are larger than spines, and generally smaller and more numerous than horns. They range from struc mix turally simple to complexly branched with intricate distal terminations. PROXIMATE DINOCYST (Major Dinocyst Type): Dinocysts in which the shape corresponds closely to the shape of the motile theca. They often exhibit periphragm structures which correspond to the girdle, sulcus and tabulation of the theca. Short sculptural features may be present, though long processes are absent from true proximate cysts. Proxi mate cysts are characterized by the ratio: (Radius of endocoel)/(Overall radius) > 0.8. (e.g., Gonyaulacysta jurassica and Gonvaulacysta palla; 13, 30.) PR0XIM0CH0RATE DINOCYST (Major Dino cyst Type): Dinocysts exhibiting morphologic features between those of proximate and chorate dinocysts. More rigorously defined as having a value between 0.6 and 0.8 for the ratio of the endocoel radius to the overall radius. They exhibit clear indications of the motile dinofla gellate tabulation by sutural out growths (e.g., Mieouroaonyaulax valensii; 30). 386 PSILATE SCULPTURE (Type of Sculp ture): A surface lacking in either positive or negative sculpture. A smooth surface. (41). PTERATE DINOCYST (Chorate Dinocyst Type): Dinocysts exhibiting pro cesses confined to the equatorial region and distally linked in such a manner as to form a wing or flange around the dinocyst (e.g., Wanaea fimbriate; 40). PTEROCAVATE DINOCYST (Cavate Dino cyst Type): Cavate dinocysts exhi biting an equatorial periocoel formed by two wall layers which are appressed in the polar regions (e.g., Stephodinium coronatum; 7). PUSTULATE SCULPTURE (Positive Sculp ture): Positive sculpture con sisting of low, small, hollow, and rounded protrusions or pustule-like structures. (41). QUADRA 2A ARCHEOPYLE (Type of 2A Archeopyle): An archeopyle formed by the loss of a four-sided, second-anterior intercalary para plate (2a). When the dinocyst is viewed with the dorsal side upper most, the margins of the quadra 2a paraplate are numbered from the top (Ql) in a counterclockwise direction around to the right-hand side (Q4). (e.g., Wetzeliella articulate; 16, 23). QUADRALATERAL (Dinocyst Shape): A dinocyst whose overall shape is four-sided; usually the longitudinal dimension exceeds the transverse dimension (e.g., Hystrichosphaer- opsis rectangularis; 4). RECURVED PROCESS TIP (Process Tips): A hollow process tip whose flared distal end is concentrically folded back around its longitudinal axis and toward the dinocyst body (e.g., Cordosphaeridlum cantharellum; 19). 388 REDUCED ARCHEOPYLE (Additional Archeopyle Features): An archeopyle formed by the loss of an operculum which separated within, rather than m along the surrounding parasutures. Thus, a flange of cyst wall is left between the parasutures surrounding the archeopyle and the actual struc ture along which the operculum sepa rated from the dinocyst (e.g., Hys- trichosphaera sp.; 15). REGULAR STRUCTURES (Structures Pre sent): Structures (e.g., septa or processes) which are basic charac teristics of a species; and are always present in well preserved specimens. They often exhibit a consistency of shape, number, and distribution (e.g., Gardodinium sp. and Cannosphaeropsis sp.; 18). RETICULATE SCULPTURE (Negative Sculpture): Sculptural features arranged in a net-like distribution. (41). RIDGE (Expression of Parasutures): An elongated thickening on the sur face of the dinocyst, (e.g., Gon- yaulacvsta palla; 30). RUGULATE SCULPTURE (Positive Sculp ture): Positive sculpture charac terized by fine, irregularly distri buted surface wrinkles. (41). SCABRATE SCULPTURE (Positive Sculp ture): Positive sculpture con sisting of very low, fine-grained bumps which create an indistinct rough surface. (41). SECATE PROCESS (Process Tips): A process tip whose distal end exhi bits flat tab-like extensions which project perpendicularly to the long axis of the process and approxi mately parallel to the surface of the dinocyst. The end of each tab may be truncated, concave, or bifur cated. (41). SEPTUM (Expression of Parasutures): An elongated projection, more or less membraneous, which extends approximately perpendicularly from the wall of the dinocyst. (16). SETOSE SCULPTURE (Positive Sculp ture): Positive sculpture with num erous, pointed, cone-shaped spines or bristles. (40). SHAGREENATE SCULPTURE (Type of Sculpture): A surface which appears roughened like the skin of a shark. (40). SIMPLE ARCHEOPYLE (Archeopyle Com plexity): An archeopyle formed by the separation or partial separation along parasutures of a single para plate. (15). SIMULATE COMPLEX (Process Complex Type): A complex of processes formed within and parallel to the boundaries of a paraplate. The simulate complex is a closed polygon whose individual processes may be joined to one another proximally, distally, or along their length (e.g., Kiaselovla tenuivirgula; 36, 38). SKOLOCHORATE DINOCYST (Chorate Dino cyst Type): Chorate dinocysts whose projections consist of processes, or processes and low septa or ridges. The processes have a length greater than four-tenths of the overall radius (e.g., Hystrichosphaeridium sp., Spiniferites sp.; 6). SOLEATE COMPLEX (Process Complex Type): Processes arranged in an open half-circle or a crescent. The processes may or may not be joined to one another at any point along their length (e.g., Areoligera cf. A. senonensist 36, 13). SPINE (Expression of Parasutures): Usually short, cone-shaped surficial projections that are often solid (e.g., Vozzhennikovia rotunda). 392 STANDARD HEXA 2A ARCHEOPYLE (Type of 2A Archeopyle): A hexa 2a archeo pyle having relatively long H2 and H6 paraplate margins and relatively short H3 and H5 paraplate margins (see HEXA 2A ARCHEOPYLE; (e.g., Spi- nidinium macrourdoense; 23). STRIATE SCULPTURE (Positive Sculp ture): Positive sculpture typified by elongate, more or less parallel grooves (striae) separating projec jT .V - . . . * M tions. The length of the sculptural elements is at least twice their breadth. (40). SUBCQNICAL PROCESS (Process Type): A process whose large proximal diam eter decreases distally and is trun cated to form a flat end distally w (e.g., Conosphaeridlum striatoconus; & 10, 9). SUBSPHERICAL (Dinocyst Shape): A cyst which appears roughly circular when viewed from any direction, though slight variations in axis length may be evident. (34). TAENIATE PROCESS (Process Type): Processes which appear to be discon tinuous membranes or flat plate-like structures more or less perpendi cular to the dinocyst (e.g., Cordos- phaeridium filosum; 42). TAPERING PROCESS (Process Type): A type of process whose relatively wide proximal diameter decreases distally in an even manner. The tip may or may not be truncated (e.g., HystrichokoIpoma eisenacki; 40, 37). 394 TRABECULATE DINOCYST (Chorate Dino cyst Type): A type of chorate dino cyst which has its processes linked distally by trabeculae (e.g., Canno- sphaeropsis utinesis; 8). TRANSAPICAL ARCHEOPYLE (Archeopyle Type): An archeopyle formed by paraplate separation along sutures extending from the apex to the para- cingulum along the lateral margins of the dinocyst. (15). TRIFURCATE PROCESS TIP (Process Tips): A process tip characterized by its distal end being split into three separate tips which are often parallel to the dinocyst surface (e.g., Spiniferites ramosus; 16, 8). TUBERCULATE SCULPTURE (Positive Sculpture): Positive sculpture characterized by knobby outgrowths. (41). 395 TUBIFORM PROCESS (Process Type): A hollow process whose immediate prox imal and distal ends are slightly flared (e.g., Hystrichosphaeridjum salplngophorum; 10, 8). UNSPIRALED PARACINGULUM (Para- cingulum Type): A parcingulum whose ends on either side of the para- sulcus do not exhibit any offset in an apical-antapical direction. (40). VERRUCATE SCULPTURE (Positive Sculp ture): Positive sculpture composed of warty shaped projections greater than 0.5 p in height or diameter. (41). REFERENCES 1. Alberti, G., 1961, Zur Kenntnis mesozoischer und alttertiarer Dino- flagellaten und Hystrichosphaerideen von Nord- und Mitteldeutsch- land sowie einigen anderen europaischen Gebieten; Paleontographica, Abt. A, v. 116, p. 1-58, pi. 1-12. 2. Artzner, D., E. H. Davies, G. Dorbofer, A. Fasola, G. Norris, and S. Poplawski, 1979. A systematic illustrated guide to fossil organic-walled Dinoflagellate Genera. Life Sciences Miscellaneous Publications; Royal Ontario Museum. 119 p. 3. Cookson, I. C., and A. Eisenack, 1958. Microplankton from Austra lian and New Guinea Upper Mesozoic Sediments. Roy. Soc. Victoria Proc., v. 70, p. 19-79, pi. 1-12. 4. , 1962. Additional microplankton from Australian Cretaceous sediments. Micropaleontology, v. 8, no. 4, p. 485-507, pi. 1-7. 5. Davey, R. J,, and G. L. Williams. 1966a. The Genera Hystricho- sphaera and Achomosphaera. In; Davey, R. J., Downie, C., Sar jeant, W. A. S., and G. L. Williams, Studies on Mesozoic and Ceno- zoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 25-52. 6. , 1966b. The genus Hystrichosphaeridium and its allies. In: Davey, R. J . , Downie, C., Sarjeant, W. A. S., and G. L. Williams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 53-106. 7. Deflandre, G. 1936. Microfossiles des silex cretaces. Premiere partie. Generalites Flagelles. Ann. Paleont., v. 25, p. 151-191, pi. 1-10. 8. , 1937. Microfossiles des silex cretaces. Deuxieme partie. Flagelles Incertae sedis Hystrichosphaerides, Sarcodines Organismes divers. Ann. Paleont., v. 26, p. 51-103, pi. 11-18. 9. Deflandre, G., and I. C. Cookson, 1955. Fossil microplankton from Australian Late Mesozoic and Tertiary sediments. Austral. Jour. Mar. Freshw. Res., v. 6 , p. 242-313, pi. 1-9. 10. Downie, C., and W. A. S. Sarjeant. 1966. The morphology, termi nology, and classification of fossil dinoflagellate cysts. In: Davey, R. J., Downie, C., Sarjeant, W. A. S., and G. L. Williams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 10-17. 11. Drugg, W. S., 1967. Palynology of the Upper Moreno Formation (Late Cretaceous-Paleocene) Escarpado Canyon, California; Palaeontologra- phica, Abt. B, v. 120, p. 1-71, pi. 1-9. 396 397 12. Eaton, E. L., 1971. A morphogenetic series of dinoflagellate cysts from the Bracklesham Beds of the Isle of Wight, Hampshire, England; In; Farinacci, A. (ed.), Proceedings Second Planktonic Conference, Roma 1970, Edizioni Tecnoscienza, Rome, v. 1, p. 355-379, pi. 1-4. 13. Evitt, W. R . , 1961. Observations on the morphology of fossil dino- flagellates. Micropaleontology, v. 7, no. 4, p. 385-420, pi. 1-9. 14. _____ , 1963. A discussion and proposals concerning fossil dino- flagellates, hystrichospheres and acritarchs, I, 11; Proc. Nat. Acad. Sci., Wash., v. 49, p. 158-164, 298-302. 15. _____ , 1967. Dinoflagellate studies II. The archeopyle. Stan ford Univ. Publ. Geol. Sci., 10, no. 3, p. 1-83, pi. 1-9. 16. _____ , 1969. Dinoflagellates and other organisms in palynological preparations. La: Tschudy, R. H. 'and Scott, R. A. (eds.), Aspects of Palynology; Wiley-Interscience, New York, p. 439-479. 17. _____ , 1970. Dinoflagellates--A selective review. Geoscience and Man, v. I, Amer. Assoc. Strat. Palyn., Baton Rouge, Louisiana, p. 29-45. 18. Evitt, W. R . , J. K. Lentin, M. E. Millioud, L. E. Stover, and G. L. Williams, 1977. Dinoflagellate cyst terminology. Geological Survey of Canada, Paper 76-24, p. 1-11. 19. Gocht, H., 1969. Formengemeinschaften alttertiaren Mikroplanktons aus Bohrproben des Erdolfeldes Meckelfeld bei Hamburg; Paleontogra- phica, Abt. B, v. 126, p. 1-100, pi. 1-11. 20. _____ , 1970. Dinoflagellaten - Zysten aus einem Geschiebefeuer- stein und ihr Erhaltungszustand; Neues Jahrb. Geol. Palaontol., Mh. p. 129-140. 21. Gocht, H., and H. Netzel, 1976. Reliefstrukturen des Kreide- Dinoflagellaten Palaeoperidinium pyrophorum (Ehr.) im Vergleich mit Panzer-Merkmalen rezenter Peridinium-Arten, N. Jb. Geol. Palaont. Abh., 152, 3, p. 380-413. 22. Klumpp, B . . 1953. Beitrag zur Kenntnis der Mikrofossilien des mitt- leren und oberen Eozan; Palaeontographica, Abt. A, v. 103, p. 377-406, pi. 16-20. 23. Lentin J. K., and G. L. Williams, 1976. A monograph of fossil per- idinioid dinoflagellate cysts. Bedford Institute Oceanography Rept. BI-R-75-16, p. 1-237 p. 24. Manum, S., 1963. Some new species of Deflandrea and their probable affinity with Peridinium. Nor. Polarinst., Arbok 1962, p. 55-67, pi. 1-3. 398 25. Millioud, M. £., 6. L. Williams, and J. K. Lentin, 1975. Stratigraphic range charts. Selected Cretaceous Dinoflagellates. In: W. S. Evitt (ed.), Contribution Series No. 4, Amer. Assoc. Strat. Palynologists, Stanford University, p. 65-72, pi. 1-12. 26. Morgenroth, P., 1968. Zur Kenntnis der Dinoflagellaten und Hystri- chosphaeridien des Danien. Geol. Jahrb., v. 86, p. 533-578, pi. 41-48. 27. Neale, J. W. and W. A. S. Sarjeant, 1962. Microplankton from the Speeton Clay of Yorkshire. Geol. Mag., v. 99, n. 5, p. 439-458, pi. 19-20. 28. Norris, G., 1965. Archeopyle structures in Upper Jurassic dinofla gellates from Southern England. N. Z. J. Geol. Geophys., v. 8, p. 792-806. 29. Sarjeant, W. A. S., 1960. New hystrichospheres from the Upper Jurassic of Dorset. Geol. Mag., v. 97, No. 2, p. 137-145, pi. 6. 30. Sarjeant, W. A. S., 1966. Dinoflagellate cysts with Gonyaulax-type tabulation. In: Davey, R. J . , Downie, C., Sarjeant, W. A. S., and G. L. Williams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 107-156. 31. _____ , 1966. Further dinoflagellate cysts from the Speeton Clay. In: Davey, R. J . , Downie, C., Sarjeant, W. A. S., and G. L. Wil liams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 199-214. 32. _____ , 1974. Fossil and living dinoflagellates. Academic Press., London and New York, 182 p. 33. Stover, L. E., and W. R. Evitt, 1978. Analyses of Pre-Pleistocene Organic-walled dinoflagellates. Stanford University Publications Geological Sciences, v. XV, 300 p. 34. Stover, L. E . , and G. L. Williams, 1977. Introduction to Tertiary dinoflagellates. Twelfth Louisiana State University Short Course, Baton Rouge, Louisiana, 41 p. 35. Vozzhennikova, T. F., 1965. Vvedenie v izuchenie iskopaemykh peri- dineevykh vodorosli; Akad. Nauk SSSR, Sib. Otd., Inst. Geol. Geofiz., Tr., 156 p. (Introduction to the study of fossil peridi- nian algae, K. Syers, trans., W.A.S. Sarjeant, ed.: Boston Spa, Yorkshire, England, Natl. Lending Library for Science and Tech nology, 1967). 36. Williams, G. L., 1978. Dinoflagellate, acritarchs and tasmanitids, in Haq, B. U. and A. Boersma (eds.), Introduction to Marine Micro paleontology, Elseiver Scientific Publishing Co., Amsterdam, p. 293-326. 399 37. Williams, G. L. and C. Downie, 1966a. The genus Hystrichokolpoma. In; Davey, R. J., Downie, C . , Sarjeant, W. A. S., and G. X. Wil liams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 176-181. 38. _____ , 1966b. Wetzeliella from the London Clay. In: Davey, R. J., Downie, C., Sarjeant, W. A. S., and G. L. Williams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 182-198. 39. _____ , 1966c. Further dinoflagellate cysts from the London Clay. In: Davey, R. J., Downie, C., Sarjeant, W. A. S., and G. L. Wil liams, Studies on Mesozoic and Cainozoic dinoflagellate cysts; Bull. Br. Mus. Nat. Hist. (Geol.), Suppl. 3, p. 215-235. AO. Williams, G. L., W. A. S. Sarjeant, and E. J. Kidson, 1973. A glossary of the terminology applied to dinoflagellate amphiesmae and cysts and acritarchs. Amer. Assoc. Strat. Paly., Contribu tions, Series No. 2, p. 1-222. 41. Williams, G. L., W. A. S. Sarjeant, and E. J. Kidson, 1978. A glossary of the terminology applied to dinoflagellate amphiesmae and cysts and acritarchs. 1978 Edition Amer. Assoc. Strat. Paly. Contributions, Series No. 2A, p. 1-121. 42. Wilson, G., 1967. Some new species of Lower Tertiary dinoflagel lates from McMurdo Sound, Antarctica, New Zealand Jl. Bot., v. 5, no. 1, p. 57-83. 400 DINOCYST DESCRIPTIVE SHEET naiE-r GEOGRAPHIC LOCATION: SECTION/DRILL CORE «t SAMPLE AND SLIDE «t _ COORDINATES: ______ SPECIMEN NAME: _____ I0LL/PHD106AAPH « : ______. HEM HRBHIF1CATJ0N:______SURFACE Bms naims HjjjQR^iMQCYST im □ gwrc M M tm TYPE ^ MAROINATE HENIRAMATE PTERRU OTHER OTHER 0 401 SAMPLE S SLIDE « l ______COORDINATES! mss FEATURES (CONJ'D) „ __ „ STRUCTURE □ lEHT PHRA8NA STRUCTURE KUTOCYST 1 PTESrHO i w h m^URE j PER1CYST 2 NONE PERI- HMD ENDOCTSTS S ONE □ PERI- NESO- ENOOCYSTS 4 NORE THAN ONE AUTOPHRABH J PERI-ENOOPHRABH 2 RgiJHs.MKai □ ANTAPICAL HORN □ PER1-NESO-ENDOPHRA8H 3 HUTDCOEl HONE T ECT0-PERI-END0PHRA8H 4 PERI-ENDDCOEL ONE 2 ECTO-RUTOPHRAOH 5 PERI- PESO- ENDDCOEL TOO (UNEOUAL LEN8TH)3 OTHER 0 ECTO- PERI- ENDOCOEL TWO (EOUAL IEN6TH) 4 ECTD- RUTOCOEL NORE THAN TNO 3 MS£NL □ ENDDCOEL r7 1 OTHER NON-RE6ULAR 2 PARRCIN8ULAR HORN □ OTHER 3 NONE I NONE 4 1-8IS0-EROD ONE 2 TWO 3 □ E D C D E D NORE THAN TNO 4 1 R]CONICAL 1 PARTIAL 2 CRRDlorORH 2 POSTCINBULAR HORN □ ABSENT 3 CERAT01D 8 NONE 1 COMPRESSED 01CONICAL 4 ONE 2 EXPRESSION OF PARASUTURES CONPRESSED CERATIDID 5 TNO 3 PRINARY □ □ C0NPRE8SED PERIDIN]010 B NORE THAN TNO 4 ELLIPSOIDAL T SECONDARY C D ELONBRTE 0 OTHER 1 FOSSAE 1 LENTICULAR 9 9RANULES 2 PENTRBONRL TO PRESERVATION l~1 PANDASUTURAL STRIAE 3 tURDRRLRTERRL 1] PROCESSES 4 BUOSPHERICRL 12 Ex K llM i i NI06ES S OTHER IS 9000 2 SEPTUM 0 FAIR 9 OPINES 7 POOR 4 . OTHER 0 H r a r * 9 ABSENT 2 COLOR OBSERVED PARAPLATES PER]CYST □ PREAPICAL m m D UNSPIRALE 1 ENOOCYST □ APICAL m DEXTROROTATORY 2 CLEAR ANTERIOR INTERCALARY CD LAEVQROTATORY 9 PALE YELLOM PRECINOULAR 1NDETERHINANT 4 DEEP YELLOW CD YELLON 0RAN6E PARACINSULAR CD Id D DAANBE POSTCINBULAR CD 1 ORANBE CROWN POSTERIOR INTERCALARY m NYP0-EP1CY8T 2 9RDNN NONE 0 OTHER ANTAPICAL m PARA9ULCAL CD OTHER CD 2- 402 SAMPLE A SLIDE «i______COORDINATES: m r m i m or SCULPTURE PROCESS CPHPLEX TYPE PRINARY SECOjOARY PRINARY SECOttARY P R I N A R Y □ AUTDCYST □ □ PERICYST □ □ SECONDARY □ PER]CYST □ □ NESOCYST □ □ LINEAR CONPLEX 1 ENDOCYST □ D ARCUATE CONPLEX 2 ME SOCYST P □ SOLEATE CONPLEX S FOSSULATE i ANNULATE CONPLEX 4 ENDOCYST □ □ FOVEOLATE 2 SINULNTE CONPLEX S PSILATE I RETICULATE S OTHER 0 SHA6REENATE OTHER 4 POSH IVE HE6ATIVE DISTRIBUTION OF SCULPTURE PROCESS TYPE NIXED PRINARY SECONDARY PRINARY INDETERMINATE PERICYST □ □ SECONDARY ffi OTHER NESOCYST □ □ ACICULAR m s i t i y e ENDOCYST D □ CONICAL R1MRT SECWOflRY SUBCONICAL NONTABULRR 1 TAPERIN6 PERICYST Q U C D INTRATABULAR 2 CYLINDRICAL NESOCYST C D C D PEN]TABULAR S INFUNDIBULAR ENDOCYST □ □ m PARASUTURAL 4 FLARED PANDASUTURAL S 1UB1F0RH SCABRATE OTHER S SUCCINATE branulate LABENATE PAPILLATE PMCFSS CMRRCTF/tlSTICS BULBOUS PUSTULATE LATISPINDUS UERRUCATE r m w □ TAENIATE OENNATE PRESENT 1 OTHER 1UBERCULATE ABSENT 2 PILATE INTERNAL PROCESS CLAVATE NUNBER OF PROCESSES I T T ! STRUCTURE BACULATE ECKlNATE PROCESS DISTRIBUTION PRINARY SETOSE ' PRINARY □ SECONDARY B STRIATE SECONDARY HOLLOW 1 SUBULATE □ DISTALLY SOLID 2 AREOLATE TERTIARY D SOLID S OTHER NOKTAIULAR OTHER 4 1NTSATABULAR PEN!TABULAR PROCESS IERH1NATION PARASUTURAL PRINARY □ PANDASUTURAL •ONAL SECONDARY □ INTEROONAL OPEN 1 OTHER CLOSED 2 AO 3 SAMPLE A SLIDE ______COORDINATES. HH3CFS5 CHMRCTERISnCS (CONl'D) COMPLEXITY MPD1TIOHAL ARCHEOPYLE PROCESS TIPS Features PRIMARY I L i PERI- NESO- ENDO- SECONDARY □ □ o 1 PERI-HESO-EMDO- CD SIMPLE J parasulcal m m m ACUMINATE COMPOUND S NOTCH L—ll —l j i—i-J EVEXATE COMBINATION 4 CAPITATE INDETERMINATE parasulcal m m m CAVLiriORATE TONGUE CLAYATE accessory m m m S1F1D PARASUTURES U L J FOLIATE IffTH P U D □ O enlarged . m m m DELATE ARCHEOPYLE L X J L J -J l _i_ i DIGITATE 1RANSAP1TCAL DRANCHED APICAL IIFURCATE INTERCALARY reduced m m m TRlfURCATE PRECINGULAR ARCHEOPYLE U J U J U J ENTIRE EPICYSTAL FENESTRATE ANTAPICAL JYPF OF 2A ARCHEOPYLE ACULEATE OTHER PERIARCHEOPYLE □ *£MTE INDETERMINATE DENTICULATE ENDOARCHEOPYLE □ RECURVED S1BTUS Of OPERCULUM 1 PATULATE PERI- NESO* MiA- STANDARD HEXA DIR]BATE DROAO HEXA 2 ORTHOGONAL p □ □ ONEBAFORN HEXA S DISTAL PLATFORM 1 ufriACE 1 ATTENUATED HEXA 4 NIXED ATTACHED. ANTERIORLY 2 DUADRA 5 OTHER ATTACHED. POSTERIORLY 8 FREE * JMCHFDPVLE FORMULA OTHER ■ PERIARCHEOPYLE aesorrcheopyle w h f /m i f atmmisTics fP M rn P Y irtS T PRESENT. □ ENDOARCHEOPYLE PERIARCHEOPYLE ENDOARCHEOPYLE . PERI-ENDOARCHEOPYLE PER1-NES0-END0ARCHE0PYLE NONE OBSERVED OTHER -4 404 SAMPLE i SLIDE *i COORDINATES! mmms m i DINEN810NS LENBTH OF PROCESSES MICAftUA LEMBTH MIDTH THICKNESS LEN6TH RRNBEi PERICYST _ N1DTH RAHSEi NESOCYST ____ _ ENDOCYST _ > OF PROCESSES NERSURED. _ LEN6TH OF HORNS APICAL ARCHEOPYLE DIHENS10H5 (INSULAR. RIBHT WIDTH HEI6HT LEFT PERICYST ______POSTCINBULAR. RIBHT NESOCYST ______LEFT ENDOCYST ______ANTAPICAL. RIBHT LEFT ARCHEOPYLE RATIDi ARCHEOPYLE INDEX. COMMENTS + PLATES The dinocyst surface and the view from which it is illustrated in each photograph is expressed with the following abbreviations. "DV" and " W " indicate dorsal view and ventral view, respectively. "DS" and "VS" indicate dorsal surface and ventral surface, respectively. "OS" indi cates the specimen is seen in optical section. The length and width of elongate specimens are recorded by "L X W:". The symbol "p" stands for microns. Slide numbers with a previs of "W" were prepared by the author, whereas a slide number prefix of "E" refers to slides prepared by the Exxon Production Research Company. The abbreviation "coords." represent coordinates as measured on the Zeiss Universal microscope (serial number 038295) belonging to the Amoco Production Company Research Center, Tulsa, Oklahoma. The letter and number(s) contained in brackets at the end of each caption refer to the Microlocator square in which the illustrated specimen can be found. For example, "(S32)" at the end of the caption indicates the specimen illustrated can be found by setting the mechanical stage of the micro scope to Microlocator square S32. When the palynological slide con taining the illustrated specimen is placed on the mechanical stage, the specimen will be in the field of view. The Microlocator slide used in this study is stored with the study slides. 405 406 Plate 1 Figures 1, 2 Ceratiopsis boloniensis (Riegel 1974) Lentin and Williams 1977b. Fig. 1 shows the parasulcus, 2a archeopyle with the operculum in place and the large hypocoel between the antapical horns. DV, DS. L X W: 112 X 78jj. Sample 8498, slide W/2, coords. 111.1 X 11.8, (M16). Fig. 2 left lateral view showing the profile of the archeopyle with the operculum in place. L X W: 119 X 65p. Sample 8498, slide W/7, coords. 122.9 X 12.3, (S28). 3, 7 Ceratiopsis striata (Drugg 1967) Lentin and Williams 1977b. Fig. 3 depicts a damaged specimen in which the apical horn has been partially pushed into the endocoel. Note the linear sculpture on the surface of the peri- phragm. DV, DS. Fig. 7 shows the apical horn and its solid, distal papillae. DV, VS. L X W: 116 X 78|J. Sample 8464, slide W/5, coords. 106.9 X 17.3, (S22). 4, 8, 9 Senegalinium asymmetricum (Wilson 1967a) Stover and Evitt 1978. Fig. 4 shows the paracingulum on the dorsal sur face. High focus, DV, DS. Fig. 8 shows the granular nature of the endocyst. DV, VS. Fig. 9. The posteri orly attached operculum is shown standing partially free of the pericyst and the endocyst. DV, DS. L X W: 94 X 68p. Sample 8511, slide E/1, coords. 133.2 X 17.9, (T39). Ceratiopsis dartmooria (Cookson and Eisenack 1965b) Lentin and Williams 1981. Fig. 5 shows the 2a endoarche- opyie and the anterior margin of the periarcheopyle. Intratabular grana are evident on the 3" paraplate below the archeopyle. W , DS. Fig. 10 shows the parasulcul area and the intratabular grana on the ventral surface. Faint parasutural lines run between the paraplate areas defined by the grana. W , VS. L X W: 134 X 70(J. Sample 8495, slide W/3, coords. 122.5 X 6.0, (F28). Ceratiopsis speciosa (Alberti 1959) Lentin and Williams 1977b. Fig. 6 shows large periarcheopyle margin and grana on periphragm. DV, DS. Fig. 11 shows parasulcus and indented paracingulum. DV, VS. L X W: 155 X 95p. Sample 8495, slide W/2, coords. 123.4 X 12.3, (M29). 1sabe!idinium druggii (Stover 1974) Lentin and Williams 1977a. The omega form 2a archeopyle with its operculum attached is evident, though distorted. Note the small circular depression in the apical horn. DV, DS. L X W: 78 X 80|J. Sample 8451, slide E/1, coords. 126.5 X 11.8, (M32). Isabelidinium pellucidum (Deflandre and Cookson 1955) Lentin and Williams 1977a. Fig. 13 depicts a specimen with short, broad endocyst. (The dark area in the endo- cyst is an air bubble.) DV, DS. L X W: 102 X 77|J. 408 Sample 8477, slide 14, coords. 108.8 X 16.7 (S14). Fig. 14 depicts a specimen which has undergone bacterial infestation. Note the circular bacterial scars. W , VS. L X W: 116 X 73p. Sample 8507, slide E/2, coords. 126.6 X 5.1, (E32). 409 Plate 2 Figures 1-4 Phthanope r id ini um echinatum Eaton 1976. Fig. 1 depicts the ventral surface. Note echinae along the margin and the short left antapical horn. W , VS. Fig. 2 shows echinae adjacent to the parasutures. Note the short, blunt apical horn. W , OS. Fig. 3 shows the rows of echinae adjacent to the paracingulum. W , DS. L X W: 51 X 43|J. Sample 8511, slide W/l, coords. 123.5 X 14.8, (P29). Fig. 4 is a right oblique view showing the para- tabulation delimited by the penetabular echinae and the 2a archeopyle. L X W: 49 X 46p. Sample 8511, slide E/1, coords. 119.3 X 4.3 (D25). 5-17 Deflandrea antarctica Wilson 1967a. Figs. 5-17 and Plate 3, Figs. 1-5 illustrate the range in morphologic variation included within Deflandrea antarctica. Fig. 5 shows a Type I specimen with a stout apical horn, broad shoulders on the epipericyst, a protruding paracingulum and posteriorly convergent epihypocystal margins. DV, DS. t X W: 127.5 X 90.Ip. Sample 8506, slide E/3, coords. 122.7 X 15.9, (R28). Figs. 6-7 show a Type 1 specimen with nontabular grana scattered about the peri- phragm. The overall shape is the same as the specimen in Plate 2, Fig. 5 except the apical horn is shorter and the 410 paracingulac projections are more developed. Fig. 6. DV, VS. Fig. 7. DV, OS. Fig. 8. DV, DS. L X W: 124 X 94p. Sample 8465, slide E/3, coords. 122.7 X 7.3 (G28). Figs. 9 and 14 show a Type I specimen with a rounded outline and little, if any, sculpture on the epi- cyst. Fig. 9, W , DS; Fig. 14, W , VS. L X W: 129 X 95m . Sample 8507, slide E/2, coords. 116.9 X 2.0, (A22). Figs. 10 and 11 show a transitional form of D. antarctica on which the granular sculpturing is well developed, but differentiation into paratabular areas is poorly developed. Fig. 10, DV, VS. Fig. 11, DV, DS. L X W: 120 X 88|J. Sample 8465, slide E/1, coords. 132.2 X 18.8 (U38). Figs. 12 and 13. A Type II specimen showing well developed paraplate areas. Fig. 12. Intra tabular granules outline the 3' and 4'* paraplates. W , DS. Fig. 13. Paraplates 1', l,,,,, and 2 1’'1 are out lined by intratabular granules. W , VS. L X V: 111 X 82p< Sample 8465, slide E/1, coords. 134.8 X 5.7, (E4l). Figs. 15-17, Type II D. antarctica. Fig. 15. Paraplate 4*' is indicated just below the 2a archeopyle by intratabular spinules. Note the highly reduced epihy- pocyst and the spines along the right margin of the dino cyst. DV, DS. Fig. 16 shows the margins of the para- sulcus outlined by folds and spines. DV, OS. Fig. 17 shows well developed spines along the margins of the dinocyst and the ventral margins of paraplates 2' and Parasutural lines are evident in the parasulcal area. DV, VS. LXW: 100 X 85|i. Sample 8506, slide E/1, coords. 123.8 X 15.8, (R29). Plate 3 Deflandrea antarctica Wilson 1967a. Figs. 1-3 show a Type II specimen with paraplates expressed by short, stout grana or short spines. Fig. 1. W , OS. Fig. 2. W , DS. Fig. 3. W , VS. IXV: 124 X 88p. Sample 8465, slide E/1, coords. 128.9 X 6.9, (F35). Figs. 4 and 5 show a Type I D. antarctica. The nontabular sculpture is widely developed as granules and spines. The endocyst also is slightly rugulate. Fig. 4. DV, VS. Fig. 5. DV, DS. L X W: 132.6 X 100.3p. Sample 8465, slide E/1, coords. 122.4 X 21.8, (X29). Deflandrea cf. phosphoritica Eisenack 1938. Figs. 6 and 7. A specimen with a broad paracingular area. Fig. 6 shows the parasulcus and comma shape "flagellar" scar. W , VS. Fig. 7 shows the 2a archeopyle. W , DS. L X W: 121 X 88|J. Sample 8463, slide E/1, coords. 116.5 X 12.4, (M22). Figs. 8 and 9 show a specimen of D. cf. phosphor itica with very slight paracingular projections. Fig. 8 shows the parasulcus and comma shaped flagellar scar. W , VS. Fig. 9 shows the 2a archeopyle. W , DS. L X W: 112 X 76|J. Sample 8463, slide E/1, coords. 116.9 X 5.1, (D22). 413 10 Deflandrea oebisfeldensis Alberti sensu Cookson and Cran- well 1967. The endocyst is subcircular and clearly sepa rated from the pericyst. W , VS. 1 X W: 128 X 94p. Sample 8474, slide W/5, coords. 115.2 X 10.9, (K20). 11-19 Deflandrea sp. A. Figs. 11-13 show a specimen bearing well developed pandasutural striae on the dorsal and ven tral surfaces. Fig. 11 ventral surface showing the para- sulcal area, "flagellar" scar and pandasutural striae on the epicyst. DV, VS. Fig. 12. DV, OS. Fig. 13 shows what appears to be a 31 endoarcheopyle. However, the apical margin is somewhat ragged, suggesting its shape is the result of tearing. Note the absence of pandasutural striae in the apical area of the endocyst. DV, DS. L X W: 105 X 77p. Sample 8511, slide E/1, coords. 117.8 X 7.9, (G23). Figs. 14 and 15. Loose operculum of Deflandrea sp. A composed of the 2a paraplate. This sug gests the archeopyle is formed by the loss of only the 2a paraplate and not by 3 anterior intercalary paraplates. Fig. 14. Perioperculum in focus. Fig. 15. Endoperculum in focus. L X W: 30 X 42jJ. Sample 8511, slide E/1, coords. 131.9 X 10.9, (J38). Figs. 16-19. A damaged specimen depicting distinctive striae and an endoarcheo pyle suggest a 31 archeopyle formula. Fig. 16. DV, DS. Fig. 17. DV, DS. Fig. 18. DV, VS. Fig. 19. DV, VS. LXV: 90 X 73p. Sample 8511/1, slide E/1, coords. 120.9 X 11.8, (L26). 414 Plate 4 Figures 1-12 Deflandrea cygniformis Pothe de Baldis 1966. Figs. 1 and 2 show a specimen bearing little or no paracingular development. Fig. 1. DV, VS. Fig. 2 shows the 2a per iarcheopyle, the continuous paracingulum on the dorsal surface, and the "flagellar" scar in the parasulcal depression. DV, DS. L X W: 182 X 163|J. Sample 8479, slide E/1, coords. 132.3 X 1.9, (A38). Figs. 3 and 4 show a specimen with very reduced paracingular projec tions. Fig. 3. W , DS. Fig. 4. W , DS. L X W: 204 X 90(J. Sample 8455, slide E/3, coords. 105.5 X 19.4, (U21). Figs. 5-6 show a specimen with a well developed perihypocyst and moderate paracingular projections. Fig. 5. DV, VS. Fig. 6. The distal end of the speci mens apical horn is rounded and solid. DV, DS. L X W: 180 X 92p. Sample 8455, slide E/3, coords. 115.4 X 19.8, (V21). Figs. 7 and 8 show a specimen with a clearly expressed 2a archeopyle, well developed paracingular pro jections, and a well developed epihypocyst. Note the separation between the endocyst and the hypocyst. Fig. 7. The periarcheopyle has a ragged, torn apical margin, and the operculum is gone. The operculum of the endoarcheopyle is outlined by parasutures and is in place. W , DS. Fig. 8. Note the scabbrate surface of 415 the pericyst. W , VS. I X W: 182 X 104|J. Sample 8479, slide E/3, coords. 121.3 X 10.7, (K27). Figs. 9-12 show a specimen with extreme development of the paracingular projections and the antapical horns. Fig. 9. Note para-, sulcus, flagellar scar, and the pitted, scabbrate surface of the periphragm. W , VS. Fig. 10. Note the truncated anterior margin of the periarcheopyle. W , OS. Fig. 11 shows the posterior outline of the periarcheopyle, the endoarcheopyle, and the displaced operculum within the endocyst. Note the surface of the endophragm. W , DS. Fig. 12 shows the continuous paracingulum on the dorsal surface. W , DS. L X W: 196 X 128p. Sample 8479, slide E/1, coords. 128.5 X 19.8, (V34). Plate 5 Phelodinium sp. A. Fig. 1 shows a damaged specimen typ ical of those encountered. Paracingulum indicated by the narrow transverse folds. W , DS. L X W: 85 X 82|J. Sample 8476, slide W/10, coords. 127.7 X 3.8, (C33). Fig. 2 shows a well preserved specimen bearing granular to rugulate sculpturing. Note flat topped apical horn, narrow paracingulum, and the small pericoel between the endophragm and the periphragm. W , DS. I X W: 116 X 116|i. Sample 8476, slide W/10, coords. 121.3 X 11.9, (M27). Lejeunecysta fallax (Morgenroth 1966b) Artzner and Dorhofer 1978. Note the solid tips on the antapical horns, the poorly developed paracingular folds, and the outline of the archeopyle. W , DS. L X W: 68 X 66|J. Sample 8477, slide W/7, coords. 118.3 X 7.3, (G24). Lejeunecysta hyalina (Gerlach 1961) Artzner and Dorhofer 1978. Note the well developed paracingular folds and thin nature of the autophragm. W , VS. L X W: 114 X I04|j. Sample 8477, slide W/14, coords. 101.5 X 9.7, (K6). Fig. 6 shows an antapical view of a specimen compressed in an apical-antapical direction. H X W: 63 X 80p. Sample 8477, slide W/14, coords. 113.2 X 19.9, (V18). Sejepgpeffpfrijt flepfrroides g e p e h e h 3 9 7 # w?n4.- $9jek 1980- jFfg. § is r n anlapiPSl yiew 9 f t h e epieyst sbwing the nniline m r g t n o f lb® o f f s e t app&enpyle. If % w* $ 3 y A 3 p. $ m p l e M 7 7 , slide W/14, eneyds.. 194.-9 % 18-9 (mi). Pflleenpeyidininm pyyaphnym (Ebyenbeyg 1898) Ssyjeani m7h- n»- h yy, vs- yig* 8- w, vs* (Phase eon- t y a s M b X W? 116 If 94p- Sample 8495, slide W/3, ppppde- j?9 ;? * 3-4, (C35)* Spinidininm sp. A- A specimen esbibibins elnsely spaced cspfpstp, penebabwlay spines. Fig* 9- The spines nni=- line bbe payasnlpal eyes and the ends nf t h e paya- Fingnlnm* W , VS- Fig* 19* W , ff§* Fig* H r Nnie papapingwlwi is nwblined by paysllel rnws o f spines: W pg. b X W= 58 If 46h• Sample 8496, siide W/8 , cnnyds* 134-6 If 19*5 (N4Q)* Spinidininm densispinamm Stanley 1965. b X W* 51 K 46p* Sample 8493, slide W/6 , eneFds* 118*8 If 9*4, 18191* Spinidininm mapmHrdnense (Wilsnn 1967a) bentin and W i H H a m s 1976* DV, 08* b X W* 105 X 75H* Sample 8457, slide W/9, eneFds* 131*6 X 19*9, (b27), 418 14 Spinidinium essoi Cookson and Eisenack 1967a. DV, DS. L X W: 63 X 44p. Sample 8468, slide E/1, coords. 120.2 X 17.1, (S25). 15, 16 Spinidinium 1antemum Cookson and Eisenack 1970a. Fig. 15. Note the 2a archeopyle with the posteriorly attached operculum pushed into the epicoel. DV, DS. Fig. 16. DV, VS. L X W: 70 X 43|J. Sample 8499, slide W/3, coords. 112.1 X 15.1, (Q17). 419 Plate 6 Figures 1 Spiniferites ramosus subsp. reticulatus (Davey and Wil liams 1966a) Lentin and Williams 1973. A poorly pre served, but typical, specimen from Seymour Island. Note the reticulate surface of the endophragm. DV, DS. L X W: 95 X 87|J. Sample 8451, slide E/1, coords. 124.5 X 4.1, (D30). 2 Dinogymnium cf. curvatum (Vozzhennikovia 1967) Lentin and Williams 1973. DV, DS. L X W: 73 X 36(J. Sample 8476, slide W/2, coords. 126.1 X 18.6, (U32). 3, 9 Palaeocystodinium granulatum (Wilson 1967b) Lentin and Williams 1976. Fig. 3 shows the epicyst of a damaged specimen. Note spinate nature of the periphragm. W , DS. L X W: 105 X 4lp. Sample 8457, slide W/9, coords. 119.0 X 12.3, (M24). Fig. 9 shows a specimen with trun cated apical and antapical horns. Orientation indetermi nate. L X W: 128 X 43|J. Sample 8457, slide W/8, coords. 120.7 X 11.9, (M26). 4, 5, 7 Palaeocystodinium australinum (Cookson, 1965 emend. Malloy 1972) Lentin and Williams 1976. Fig. 4. Right lateral view of a complete specimen showing the outline of the 2a intercalary archeopyle at the upper left. L X V : 201 X 36p. Sample 8498, slide W/3, coords. 125.5 X 13.7, (N31). Fig. 5 shows a hypocyst of P. australinium. I X W: 95 X 43p. Sample 8498, slide W/7, coords. 121.6 X 10.3, (K27). Fig. 7. Note pre- cingular archeopyle and endocyst. W , VS. L X W: 204 X 41p. Sample 8498, slide W/3, coords. 132.9 X 12.9, (M39). Pareodinia sp. Left lateral view of a specimen exhi biting an archeopyle. L X W: 99 X 46m * Sample 8509, slide W/8, coords. 105.5 X 15.3, (Q21). Palaeocystodinium golzowense Alberti 1961. DV, DS. L X W: 112 X 34p. Sample 8495, slide W/3, coords. 113.8 X 9.7, (J19). Forma-A. Fig. 10 shows a specimen with coarse, linear sculpturing. Note the darkened area at the base of each horn. L X W: 88 X 30p. Samples 8470 (maceral), slide 1, coords. 103.4 X 9.2, (J8). Fig. 11. L X W: 70 X 32m * Sample 8490 (maceral), slide 2, coords. 108.3 X 10.7, (L13). Figs. 12-14 show a specimen exhi biting apical and antapical horns and an (?)intercalary archeopyle. L X W: 121 X 30m . Sample 8470 (maceral), slide 1, coords. 108.5 X 15.0, (Q13). Fig. 15 shows a specimen with a long apical horn and an intercalary archeopyle. L X W: 111 X 24m . Sample 8470 (maceral), slide 2, coords. 97.0 X 16.6, (SI). Fig. 16. L X 90 X 37(J. Sample 8506 (maceral), slide 2, coords. 107.4 X 10.7, (L12). Plate 7 Vozzhennikovia apertura (Wilson 1967a) Lentin and Wil liams 1976. Note the distinct paracingulum and para sulcus. The parasulcus is devoid of spines. Fig. 1. W , DS. Fig. 2. W , DS. Fig. 3. W . OS. Fig. 4. W , VS. L X W: 43 X 39y. Sample 8463, slide 3, coords. 129.1 X 9.8, (K35). Cyclopsiella elliptica Drugg and Loeblich 1967. W , DS. L X W: 56 X 54p. Sample 8462, slide 1, coords. 132.0 X 14.6, (P38). Vozzhennikovia rotunda (Wilson 19678'), Lentin and Williams 1976. Fig. 6. Spines generally nontabularly distrib uted. Spines are linear adjacent to the paracingulum. W , VS. L X W: 53 X 37p. Sample 8511, slide E/1, coords. 122.5 X 19.3, (U28). Fig. 7. W , VS. L X W: 68 X 60|i. Sample 8463, slide E/1, coords. 132.9 X 6.4, (F39). Fig. 8. W , VS. L X W: 49 X 36y. Sample 8506, slide W/l, coords. 120.7 X 5.5, (E26). Cyclopsiella trematophora (Cookson and Eisenack 1967a) Lentin and Williams 1977b. Note circular opening with its thickened rim on the left side of the specimen. L X W: 107 X 80y. Sample 8511, slide W/4, coords. 120.3 X 8.1, (H26). 423 10, 16-20 Alterbia sp. A. Fig. 10 depicts the serrated outline characteristic of Alterbia sp. A. Note the concave apex and spikelike left antapical horn. W , OS. L X W: 68 X 54(J. Sample 8477, slide E/3, coords. 122.0 X 15.5, (Q27). Fig. 16. W , VS. L X W: 85 X 51|J. Sample 8477, slide E/1, coords. 125.6 X 18.5, (U31). Figs. 17-20 show the attenuated 2a archeopyle with its posteriorly attached operculum, the paracingular and par- asulcal areas. Fig. 17 depicts the shape of the endocyst and the serrated pericyst. DV, OS. Fig. 18 shows the archeopyle with its operculum attached and the continuous paracingulum on the dorsal surface. Note the apical con cavity on the serrated crests. DV, DS. Fig. 19 shows the parallel crests adjacent to the paracingulum and the folds delimiting the parasulcus. DV, VS. Fig. 20 shows the serrated crests on the pericyst margin and the oper culum buckled inward into the epicoel. DV, DS.. I X W: 87 X 76|J. Sample 8452, slide E/1, coords. 118.3 X 11.4, (L23). 11, 12 Kallosphaeridium cf. capulatum Stover 1977. Fig. 11 shows the accessory archeopyle sutures and low granular sculpture. Fig. 12 shows the attached operculum pushed down into the autocoel. L X W: 29 X 31|J. Sample 8498, slide E/7, coords. 115.7 X 6.9, (G21). 424 13-15 Cerebrocysta bartonensis Bujak 1980. L X W: 31 X 31|J. Sample 8498, slide 2, coords. 104.4 X 6.9, (G9). 425 Plate 8 Figures 1, 2 Diconodinium cristatum Cookson and Eisenack 1974 emend. Morgan 1977. Fig. 1. DV, OS. Fig. 2 shows the antap ical "keel" distinctive of this species. DV, VS. L X W: 87 X 60fJ. Sample 8476, slide E/5, coords. 117.5 X 3.6, (C23). 3, 4 Diconodinium multispinum (Deflandre and Cookson 1955) Eisenack and Cookson 1960 emend. Morgan 1977. Fig. 3. Note truncated and capitate spines. DV, VS. Fig. 4 shows the bifid apical horn. DV, DS. L X W: 92 X 54p. Sample 8443, slide E/1, coords. 131.5 X 12.3, (M37). 5-7 Cribroperidinium edwardsii (Cookson and Eisenack 1958) Davey 1969a. Fig. 5 depicts the parasulcal area and the coarse granulation and spines on the ventral surface. DV, VS. Fig. 6 shows the stout apical horn and thick periphragm. DV, OS. Fig. 7 shows the gaping precingular archeopyle and the heavy margins surrounding the opening. DV, DS. L X W: 138 X 136p. Sample 8508, slide E/2, coords. 124.7 X 8.3, (H30). 8-10 Cribroperidinium muderogense (Cookson and Eisenack 1958) Davey 1969a. Fig. 8 shows the parasulcal area slightly left of center. Note the accessory parasutures and the 426 extreme anterior-posterior displacement of the para cingulum. W , VS. Fig. 9. Note short spines capping some parasutural ridges. W , OS. Fig. 10 shows the stout apical horn. W , DS. L X W: 136 X 87p. Sample 8463, slide E/1, coords. 131.0 X 2.7, (B37). 11 Cyclonephe1ium distinctum Deflandre and Cookson 1955 emend. Stover and Evitt 1978. Damaged specimen showing the parasulcal notch and a pronounced left antapical pro tuberance. W , VS. L X W: 104 X 102|J. Sample 8503, slide W/5, coords. 119.0 X 11.4, (L24). 12-14 Aptea securigera Davey and Verdier 1974. Fig. 12 shows a variety of processes, including a distinctive ax shaped process. W , VS. Fig. 13. Note variation in process shape. W , OS. Fig. 14. Note accessory archeopyle sutures between the precingular paraplates. W , DS. L X W: 80 X 111|J. Sample 8451, slide E/1, coords. 114.2 X 13.7, (P19). Plate 9 Iropletosphaeridium sp. A. Fig. 1 and 2. Phase contrast photographs illustrating the nontabular whiplike pro cesses with capitate and bifid process terminations. Fig. 3. Note finely granular surface on the central body. L X W: 30 X 2 4 | j ; processes <10|J long. Sample 8500, slide W/3, coords. 112.0 X 7.3, (S17). Comasphaeridium cometes (Valensi 1948) DeConnick 1969. L X W: 15 X 20|J; processes 4p long. Sample 8499, slide W/3, coords. 120.7 X 19.3, (U26). Impletosphaeridium sp. C. Note the narrow, solid dis- tally acuminate processes. The impression of flexibility given by the processes is characteristic for this spe cies. L X W: 31 X 26|j; processes <10|J long. Sample 8496, slide W/8, coords. 114.2 X 20.7, (W19). Tanyosphaeridium Xanthiopyxides (0. Wetzel 1933b) Stover and Evitt 1978. Fig. 8 shows the terminations of the distally flared hollow processes. Fig. 9 shows the gran ular surface of the central body. L X W: 29 X 20p; pro cesses <16jj long. Sample 6495, slide W/3, coords. 122.1 X 13.7, (P27). Micrhystridium sp. A. Note the dense pattern of solid, acuminate spines. L X W: 32 X 26p; processes <8|J long. Sample 8457, slide W/9, coords. 110.5 X 15.2, (Q15). Xylochoarion cf. hacknessense Erkman and Sarjeant 1978. The specimen bears hundreds of nontabular capitate or bifurcate processes. L X V; 23 X 20|j; processes <10p long. Sample 8467, slide E/1, coords. 132.4 X 12.5, (M38). Hystrichosphaeridium parvum Davey 1969b. Note granular endocyst and broad, delicate processes. Diameter endo cyst 25|J; processes <7p. Sample 8504, slide W/7, coords. 123.8 X 1 8 .6 , (U29). Oligospharidium pulcherrimum (Deflandre and Cookson 1955) Davey and Williams 1966b. Note distally flared and fenestrate processes. Fig. 15. DV, DS. Fig. 16. DV, OS. Diameter (central body) 44p; processes to 24p. Sample 8479, slide W/6, coords. 111.3 X 6.3, (F16). 429 Plate 10 Figures 1-3 Hystrichosphaeridium tubiferum subsp. brevispinum (Davey and Williams 1966b) Lentin and Williams 1973. Note the distally flared and closed processes. Fig. 1. W , VS. Fig. 2. W , OS. Fig. 3 shows the closed terminations on the hollow processes. W , DS. Diameter of the central body 37p; processes coords. 114.9 X 13.6, (N20). 4-6, 10, 11 Hystrichosphaeridium sp. A. Fig. 4 shows the distal, fenestrate platforms on the hollow processes. Note oper culum of the apical archeopyle has been pushed down into the endocoel. W , DS. Fig. 5. Note the flexibility of the processes. W , OS. Fig. 6 shows apical processes projecting out of the endocoel. W , VS. Diameter of the central body 39p; processes <30|J. Sample 8500, slide W/l, coords. 116.8 X 21.8, (X22). Figs. 10 and 11 show another specimen with the apical operculum sunken within the endocoel. Fig. 10. Note the hollow processes. DV, OS. Fig. 11. Note the distal terminations. DV, DS. Diameter of the central body 4lp; processes <29|J. Sample 8463, slide E/1, coords. 126.6 X 18.4, (T32). 7-9 Operculodinium bergmannii (Archangelsky 1969a) Stover and Evitt 1978. Fig. 7 shows the granular surface of the 430 central body. Fig. 8 shows the processes around the margin of the central body. Precingular archeopyle is open to the left. Fig. 9 depicts the detail of the non- tabular processes. Note the split base on many pro cesses. I X W: 56 X 48p; processes <9|J. Sample 8511, slide E/1, coords. 113.5 X 4.4, (D18). 12, 13 Hystrichosphaeridium salpingophorum Deflandre 1935 emend. Davey and Williams 1966b. Fig. 12. Right lateral view, upper surface in view. Fig. 13. Right lateral view, lower focus in view. Diameter of the central body 36|J; processes <19fJ. Sample 8495, slide W/3, coords. 118.5 X 19.3, (U24). Plate 11 Spiniferites ramosa subsp. granosus (Davey and Williams 1966a) Lentin and Williams 1973. Fig. 1. Left lateral view showing the granular surface of the endocyst. Fig. 2 is an optical section in left lateral view. Fig. 3 shows the right side in left lateral view. L X W: 53 X 44p; processes <17|J. Sample 8464, slide W/l, coords. 119.9 X 17.5, (T25). Spiniferites cf. cornutus (Gerlach 1961) Sarjeant 1970. Note that the long apical process is somewhat ventrally located. L X W: 49 X 32 jj; processes slide W/4, coords. 110.9 X 14.6, (Q16). Spiniferites ramosus subsp. multibrevis (Davey and Wil liams 1966a) Lentin and Williams 1973. Fig. 5. Right lateral view of the left side of the endocyst. Fig. 6. Right lateral view of the right side. L X W: 60 X 54(j; processes <12|J. Sample 8463, slide E/1, coords. 129.5 X 12.0, (M35). Forma-B. Fig. 7 shows the branching terminations on the hollow processes. Fig. 8 shows the finely granular endo- phragm and the low ridges connecting the process bases. L X W: 34 X 27(i. Sample 8500, slide W/6, coords. 432 126.7 X 14.8, (Q32). Figs. 9 and 10. Diameter of the central body: 30|j; processes <11|J. Sample 8500, slide W/7, coords. 131.0 X 16.0, (R37). 11-15 Aiora fenestrata sensu Wilson 1967a. Fig. 11 shows the apical operculum in place. Fig. 12 shows the detail of the flat, fenestrate ribbon-like processes and connecting membranes. Fig. 13. Note detached process on right side of central body. Fig. 14. Note large antapical process. Fig. 15 shows details of the processes and the large win dows outlined by the connecting membranes. L X W of the process network: 90 X 102(j; L X W of the central body: 77 X 40m • Sample 8500, slide W/10; coords. 119.0 X 6.5, (F24). 433 Plate 12 Figures 1-3 Spiniferites ramosus subsp. roultibrevis (Davey and Wil liams 1966a) Lentin and Williams 1973. Fig. 1. Left lateral view of an optical section. Figs. 2 and 3. Left lateral view of the left side. L X W of the central body: 43 X 37|J; processes E/1, coords. 131.3 X 17.3, (S37). 4-8 Impletosphaeridium sp. B. Figs. 4, 5, and 8 show a spe cimen with a granular endophragm and numerous distally bifurcate processes. Central body L X W: 20 X 19p; spines < 6 | J . Sample 8500, slide W/6, coords. 130.5 X 14.1, (P36). Figs. 6 and 7 show a specimen with an opening in the wall which may be an apical archeopyle. Central body diameter 25|J; processes <10|J. Sample 8511, slide E/1, coords. 124.8 X 21.7, (X30). 9, 10 Baltisphaeridium ligospinosum DeConnick 1969. Fig. 9 shows the nontabular distribution of the solid processes. Diameter of central body 26|J; processes <8p. Sample 8495, slide W/10, coords. 115.7 X 19.5, (V21). Fig. 10. Diameter of central body 20p; processes <7|J. Sample 8495, slide W/3, coords. 118.5 X 14.6, (P24). OligoBphaeridium complex (White 1842) Davey and Williams 1966b. Fig. 11 shows the hollow infundibular processes in the pre- and postcingular areas. DV, VS. Fig. 12 shows the outline of the central body. DV, DS. Central body L X W: 37 X 27^. Sample 8495, slide W/10, coords. 113.5 X 5.3, (E18). Spiniferites ramosus (Ehrenberg 1838) Loeblich and Loeb- lich 1966. Fig. 13. Right lateral view of the right side. Fig. 14. Optical section seen from the right side. Fig. 15. Right lateral view of the left side. Diameter of the central body: 43|J; processes <9|J. Sample 8463, slide E/1, coords. 132.0 X 13.9, (P38). Turbiosphaera filosa (Wilson 1967a) Archangelsky 1969a. Fig. 16 shows the surface sculpture on the central body and the precingular archeopyle. W , DS. Fig. 17 shows the distribution of the processes. Note the large apical structure. W , VS. Fig. 18. W , OS. L X W: 77 X 53|J; processes <22p. Sample 8464, slide W/l, coords. 122.0 X 8.3, (H27). 435 Plate 13 Figures 1-13 Areosphaeridium diktyoplokus (Klumpp 1953) Eaton 1971. Fig. 1 shows a specimen with fenestrate distal platforms and processes. The operculum is dislodged slightly. DV, VS. Fig. 2. DV, DS. Central body L X W: 53 X 46p. Sample 8500, slide W/9, coords. 120.9 X 11.8, (1126). Fig. 3 shows a specimen whose processes are frequently branched proximally. Central body diameter 54p; pro cesses <19(J. Sample 8476, slide W/6, coords. 115.4 X 18.0, (T21). Figs. 4-6 show a specimen with fenestrate processes and well developed distal platforms. Fig. 4. Antapical view of the epicyst and archeopyle. Fig. 5. Antapical view of the antapex. Fig. 6. Optical section as seen from the antapex. Central body L X W: 53 X 48p; processes <22p; Sample 8467, slide W/6, coords. 113.3 X 11.4, (L18). Figs. 7-9 show a specimen with ragged, well developed fenestrate processes and a granular central body. Fig. 7. DV, VS. Fig. 8. DV, OS. Fig. 9. DV, DS. Central body L X W: 66 X 62|J; processes <48)J. Sample 8 5 0 0 , slide W/9, coords. 120.2 X 11.1, (L25). Fig. 10 shows a specimen with very thin processes, some of which have been truncated by physical damage. Central body L X W: 56 X 44p; pro cesses <19p. Sample 8467, slide W/6, coords. 436 116.6 X 12.4, (M24). Figs. 11-12 show a specimen with short thick processes which have folded back on them selves. Note distal platforms. Central body L X W: 58 X 77|J; processes <24p. Sample 8500, slide W/5, coords. 127.9 X 12.6, (M34). Fig. 13 shows a specimen with extremely short, broad processes. Central body I X W: 46 X 60p; processes W/l, coords. 118.5 X 12.9, (N24). 437 Plate 14 Figures 1-3 Hystrichosphaeridium cf. astartes Sannemann 1955. Fig. 1 shows the pattern formed by the bases of the processes. Fig. 2 shows the cross-section of some processes. Fig. 3 shows the cross-sections of the central body and the pro cesses on its margin. L X V: 42,5 X 42.5p. Sample 8462, slide E/1, coords. 124.5 X 4.6, (D30). 4 Cometodinium cf. whitei (Deflandre and Courteville 1939) Stover and Evitt 1978. Fig. 4 shows two specimens bearing numerous thin, solid processes. L X W (upper specimen): 27.2 X 27.2p. L X W (lower specimen); 34 X 28.9|J. Sample 8509, slide W/8, coords. 114.6 X 18.8, (U20). 5-7 Operculodinium bergmannii (Archangelsky 1969a) Stover and Evitt 1978. Fig. 5. W , VS. Fig. 6 shows a cross- section of the central body covered by capitate pro cesses. W , OS. Fig. 7 shows the precingular archeo- pyle. W , DS. Central body, L X W: 45 X 4l(j; processes <17|J. Sample 8512, slide W/10, coords. 131.4 X 14.3, (P37). 8 Spiniferites ramosus subsp. granomembranaceus (Davey and Williams 1966a) Lentin and Williams 1973. Note the gran- 438 ular nature of the endocyst and the clear membranes con necting the short trifurcate processes. The operculum is partially visible on the right. Left lateral view. L X W: 64.6 X 61.2&J. Sample 8494, slide W/l, coords. 127.3 X 10.9, (K33). Paralecaniella indentata (Deflandre and Cookson 1955) Cookson and Eisenack 1970b emend. Elsik 1977. L X W; 51 X 47.6p. Sample 8492, slide W/3, coords. 108.9 X 19.1, (U14). 10, 11 Odontochitina cf. operculata (0. Wetzel 1933a) Deflandre and Cookson 1955. Fig. 10 shows the entire specimen. W , VS. Fig. 11 shows the spines scattered over the per- iphragm and the nipple-like extension of the endocyst into the cavity of the antapical horn. W , VS. L X W: 144.5 X 90.9|J. Sample 8476, slide E/5, coords. 122.4 X 11.0, (L28). 12-15 Alisocysta circumtabulata (Drugg, 1967) Stover and Evitt 1978. Fig. 12 shows the parasulcal area. W , VS. Fig. 13 shows the parasulcal notch in the apical archeo- pyle margin. W , VS. Fig. 14 shows the cross-section of the central body and the lateral paraplate areas. W , OS. Fig. 15 shows the 4 1,1 paraplate and adjacent panda- sutural areas. W , DS. L X W: 47.6 X 47.6p. Sample 8497, slide W/7, coords. 116.2 X 12.4, (M21). 439 Plate 15 Figures 1, 7 Thalassiphora velata (Deflandre and Cookson 1955) Eise- nack and Gocht 1960. Fig. 1 shows the details of the apical attachment between the periphragm and the endo- phragm. Fig. 4 is a composite photograph showing the fibrous periphragm and its points of attachment to the endophragm. Note precingular archeopyle outline on the granular endocyst. Endocyst diameter 94p; pericyst diam eter 173|J. Fig. 7 shows the details of the antapical attachment point. Sample 8465, slide W/4, coords. 108.4 X 15.9, (R13). 2, 3, 5, 6 Impagidinium maculatum (Cookson and Eisenack 1961b) Stover and Evitt 1978. Fig. 2. Left lateral view of the dorsal surface. Fig. 3. Optical section of the left lateral view. Figs. 5 and 6. Left lateral view of the ventral surface. L X W: 48 X 43|J. Sample 8490, slide W/8, coords. 124.1 X 11.4, (L30). 8 , 9, 11, 12 Impagidinium victorianum (Cookson and Eisenack 1965a) Stover and Evitt 1978. Fig. 8 shows the reduced pre cingular archeopyle and the paracingulum. DV, DS. Fig. 9. DV, DS. Fig. 11 shows the low parasutural mem branes on the margin of the dinocyst. DV, OS. Fig. 12 shows the parasulcal area. DV, VS. L X W: 70 X 77p. Sample 8512, slide W/10, coords. 120.3 X 9.0, (J27). 440 10 Thalassiphora pelagica (Eisenack 1954) Eisenack and Gocht 1960. Note the outline of the precingular archeopyle and the short antapical projection. (Composite photograph). OV, DS. Endocyst diameter: 92|i. Pericyst diameter: 187p. Sample 8500, slide W/20, coords. 107.2 X 5.2, (E22). 441 Plate 16 Figures 1, 2 Palambages Forma B Manum and Cookson 1964. Fig. 1 shows a colony consisting of eight individual bodies. An angular opening is seen in lateral view on the lower right body. Colony diameter: 66|J. Fig. 2 shows the detail of the coarse granular sculpture on the middle and lower two individual bodies. Sample 8495, slide W/10, coords. 129.2 X 8.2, (H35). 3 Palambages morulosa 0. Wetzel 1961. 1 X W: 162 X 131(J. Sample 8479, slide E/3, coords. 135.0 X 4.5, (H41). 4-6 Palambages Type 1. Fig. 1 shows a colony and the distri bution of the strands forming the skeletal network of the individual bodies. I X W: 95 X 94|J. Fig. 5 is a closeup view of the network of strands and the thin mem brane covering the strand network. Sample 8 4 7 6 , slide W/2, coords. 1 1 9 . 6 X 1 6 . 8 , (S25). Fig. 6 shows an angular opening in the wall of one individual body. Field of view 56p square. Archeopyle L X W: 9 X 7jj. Sample 8479, slide E/3, coords. 135.5 X 5.9, (E41). Cymatiosphaera sp. Diameter of the inner body 32|J, diam eter of the outer body 39p. Sample 8447, slide E/2, coords. 114.6 X 7.6, (G20). Ophiobolus lapidaris 0. Wetzel 1933a emend. Evitt 1968. I X W: 31 X 20p. Sample 8501, slide W/2, coords. 114.3 X 10.9, (119). Pterospennella australiensis (Deflandre and Cookson 1955) Eisenack 1972. I X W (outer body): 54 X 43m . L X W (inner body): 27 X 19p. Sample 8478, slide W/4, coords. 123.1 X 5.4, (E28). Leiofusa .jurassica (Cookson and Eisenack 1958. Central body L X W: 24 X 12m ; projections <16m - Sample 8502, slide W/2, coords. 113.3 X 10.0, (K18). Chytroeisphaeridia explanata Bujak 1980. L X W: 95 X 87(J. Sample 8503, slide W/4, coords. 107.8 X 15.3, (Q13). Eyrea nebulosa Cookson and Eisenack 1971. Note the poorly defined, nebulous outer wall. Periphragm diam eter: 87m ; endophragm diameter: 50p. Sample 8512, slide W/6, coords. 122.9 X 14.4, (P28). Botryococcus sp. L X W: 36 X 26p* Sample 8511, slide E/1, coords. 120.5 X 17.6, (T26). Trigonopyxidia ginella (Cookson and Eisenack 1960a) Downie and Sarjeant 1965. Note the small endocyst and the smooth archeopyle margin. I X W: 51 X 56p> Sample 8497, slide W/10, coords. 104.8 X 8.6, (H20). 443 Plate 17 Figures 1 A dinocyst with a long apical horn, precingular archeo pyle, parasutural septa delimiting paraplates, and a con tinuous paracingulum. (Gonyaulacysta jurassica. Redrawn from Evitt, 1969.) 2 Chorate dinocyst with a precingular archeopyle, large process at both poles and distinctive paracingular pro cesses. (Cordosphaeridium filosum. Redrawn from Wilson, 1967.) 3 A chorate dinocyst with a precingular archeopyle, promi nent antapical processes and undelimited paracingulum. (Coronifera sp. Redrawn from Evitt, 1969.) 4 A ceratioid dinocyst exhibiting one apical, one antap ical, and one post-cingular horn. The operculum of the apical archeopyle is slightly displaced from the rest of the dinocyst. The paracingulum is continuous, indicating the dorsal surface is in view. (Pseudoceratiuro ludbrooki Redrawn from Evitt, 1969.) A chorate dinocyst exhibiting an apical archeopyle, dis tinctive processes on the paracingulum, parasulcus, and at the antapical pole. (Hystrichokolpoma cinctum. Redrawn from Evitt, 1969.) A proximate dinocyst with an apical horn, apical archeopyle suture and a paracingulum indicated by a tran sverse band devoid of sculpturing. (Chlamydophorella nyei. Redrawn from Evitt, 1969.) A dinocyst exhibiting an antapical archeopyle. (Tubercu- lodinium sp. Redrawn from Williams, 1978.) A proximate dinocyst with an epicystal archeopyle. (Dichadogonyaulax schizoblata. Left lateral view; redrawn from Sarjeant, 1974.) Bicavate dinocyst with a paracingulum clearly delimited by two parallel rows of hairlike processes. An archeo pyle has never been observed in this species. (Palaeoh- ystrichophora infusorioides. Redrawn from Evitt, 1969.) 445 Plate 18 Figures 1 Left lateral view of a dinocyst with a precingular arche opyle. The operculum can be seen within the autocoel. Note the smooth, even margin of the archeopyle. No evi dence of the paracingulum or the parasulcus can be seen. (Chytroeisphaeridia chytroeides; specimen provided by Dan N. Beju.) 2 Although this is a right lateral view, the specimen is oriented as if the archeopyle was apical in position. Note, however, that the archeopyle margin is smooth, rather than zigzag like the margin of an apical archeo pyle. (Chytroeisphaeridia chytroeides; specimen provided by Dan N. Beju.) 3 The offset paracingulum is interpreted by the parasulcus, which is located on the hypocyst and the epicyst. The left end of the paracingulum is more anteriorly located than the right end. (Psaligonyaulax deflandrei, ventral view of the ventral surface; redrawn from 30.) Two post-paracingular horns are evident; the one on the right is larger. (Muderongia cf. simplex, dorsal view of the dorsal surface; specimen provided by Evan J. Kidson.) 4 The parasulcus and paracingulum are indicated by unorna mented depressions or grooves. Note that the parasulcus is confined to the hypocyst. (Vozzhennikovia apertura, ventral view of the ventral surface.) The paracingulum is expressed by a shallow groove. The parasulcus continues from the hypocyst up onto the epi cyst, where it terminates in a parasulcal notch. (Gener alized dinocyst, ventral view of the ventral surface; redrawn from Evitt, 1969.) A peridinioid dinocyst with two antapical horns of equal length. Note the intercalary archeopyle on the dorsal surface of the epicyst. (Wetzeliella irtyschensis, dorsal view of the dorsal surface; redrawn from Alberti, 1961.) The single paracingular horn is on the right and the antapical horn is on the left. Note that the operculum with its long apical horn is just barely separated from the epicyst. (Dorsal view of the dorsal surface; spe cimen provided by Evan J. Kidson.) 447 PLATE 1 448 PLATE 2 _ / / 450 iliippr 451 PLATE 5 452 453 PLATE 7 454 PLATE 8 455 PLATE 9 456 pymio 457 PLATE 11 458 459 PLATE 13 PLATE 14 si aivid 462 PLATE 16 463 PLATE 17 464 PLATE 18 Vitae Name: John Harry Wykoff Wrenn Date of Birth: August 9, 1944 Place of Birth: Newark, New Jersey Citizenship: United States High School: Arlington Heights High School Arlington Heights, Illinois Graduated: June, 1962 Military Service: United States Marine Corps June, 1962 to June, 1965 Undergraduate Education: William Rainey Harper College Palatine, Illinois Associate of Science, June, 1972 Northern Illinois University DeKalb, Illinois Bachelor of Science (Geology) December, 1974 Graduate Education: Northern Illinois University DeKalb, Illinois Master of Science (Geology) May, 1977 Louisiana State University Baton Rouge, Louisiana Ph.D. (Geology) August, 1982 PUBLICATIONS: Papers: 1973a Read, D., Wrenn, J., and J. Delaney. An anal ysis of trace metals in the bottom sediments and water of the Fox River, in: Cadium, Copper, Lead and Zinc: Trace Metal Pollutants in an Aquatic Ecosystem by Anderson, R. V. NSF Grant GY-10814, 1973. 465 466 1973b Wrenn, J., and M. G. Mudrey, Jr. Disposition of core from DVDP 1 and DVDP 2. Dry Valley Drilling Project Bulletin No. 3: 108-113. 1974 Chapman-Smith, M . , Luchman, P. and J. Wrenn. Geologic logs of DVDP 8 and 9 New Harbor. Dry Valley Drilling Project Bulletin No. 3: 137-147. 1975 Webb, P. N. and J. H. Wrenn. Foraminifera from DVDP Holes 8, 9, and 10, Taylor Valley, Antarctica. Antarctic Journal of the U.S., 10 (4): 168-169. 1976b Wrenn, J. H. Microfossils, key to Antarcti ca's history. News Bits. Long Year Manufac turing Co. Minneapolis, Minnesota. March- April: 11. 1976c Wrenn, J. H. and P. N. Webb. Microfossils from Taylor Valley, Antarctica. Antarctic Journal of the U.S., 11 (2): 82-85. 1979 Wrenn, J. H . , An Operations Manual for the Scanning Electron Microscope Installation. Department of Geology, Louisiana State Univer sity. 67 p. 1981 Wrenn, J. H. and S. W. Beckman. Maceral and Total Organic Carbon Analyses of DVDP Drill Core No. 11 In: L. D. McGinnis (ed.), A.G.U./Antarctic Research Series, 33: 391-402. 1982a Wrenn, J. H. and S. W. Beckman. Maceral, Total Organic Carbon, and Palynological Anal yses of Ross Ice Shelf Project Site J9 Cores. Science, 216: 187-189. 1982b Wrenn, J. H. and P. N. Webb. Physiographic analysis and interpretation of the Ferrar Gla cier - Victoria Valley area. In: C. Craddock (ed.), Antarctic Geoscience, I.U.G.S. Series B: 1117-1131. 1982c Webb, P. N. and J. H. Wrenn. Late Cenozoic micropaleontology and biostratigraphy of eastern Taylor Valley, Antarctica. In: C. Craddock (ed.), Antarctic Geoscience, I.U.G.S. Series B: 1091-1099. 467 ABSTRACTS: 1976a Webb, P. N. and J. H. Wrenn. Interpretation of foraminiferal assemblages from Lower Taylor Valley (DVDP 8-12) (abstract). Dry Valley Drilling Project Seminar II, Wellington, New Zealand. DVDP Bulletin No. 7, 105-107. 1976b Webb, P. N. and J. H. Wrenn. Fossil Fiords, Victoria Land, Antarctica (Abstract). 69th Annual Meeting of the Illinois Academy of Sci ence. Knox College, Galesburg, Illinois. 1976c Wrenn, J. H. and P. N. Webb. A microfaunal reconnaissance of core material from lower Taylor Valley (DVDP 8-12) (Abstract). Dry Valley Drilling Project Seminar II, Well ington, New Zealand. DVDP Bulletin No. 7, 108-109. 1976d Wrenn, J. H. and P. N. Webb. A Micropaleonto- logical reconnaissance of Taylor Valley, South Victoria Land, Antarctica (Abstract). First Annual Student Conference in Earth Science. Milwaukee, Wisconsin. 1977a Webb, P. N. and J. H. Wrenn. Late Cenozoic micropaleontology and biostratigraphy of eastern Taylor Valley, Antarctica. (Abstract). Third Symposium on Antarctic Geology and Geophysics. August 22-27, 1977. University of Wisconsin, Madison, Wisconsin. Volume of Abstracts, p. 159. 1977b Wrenn, J. H. and P. N. Webb. Physiographic analysis and interpretation of Ferrar Gla cier - Victoria Valley area. (Abstract). Third Symposium on Antarctic Geology and Geo physics. August 22-27, 1977. University of Wisconsin, Madison, Wisconsin, Volume of Abstracts, p. 167. 1978 Wrenn, J. H. and S. W. Beckman. Maceral and total organic carbon analysis of DVDP core No. 11. (Abstract). Dry Valley Drilling Pro ject Seminar III. Tokyo, Japan. June 3-7, 1978. DVDP Bulletin No. 8, p. 116-118. EXAMINATION AND THESIS REPORT ranHiilaM? John H. Wrenn Major Field: Geology Title of Thesis: D Inocystbiostratigraphy of SeymourIsland, Palmer Peninsula, Antarctica, Approved: Chairman Dean of the Graduate EXAMINING COMMITTEE: Date of Examination: May 18, 1982 ______MICROPLflNKTON oeb i sfel dens i s sensu C&C i dens sfel i oeb sp, A sp. cygniformis Cf, phosphoritico Deflondrea antorctica D, antorctica Type I Type II Diconodinium cristatumD, mu115spinum um disperti turn i in id Impag I. sp. I. sp. B I, sp. C Isabelidinium druggiiI. pellucidum KalLosphaeridium Leiofusa cf. capulatum jurassica Lejeunecysta ax all f L, hyolino Cometodinium c fCribroperidiniumuhitei , Cyclonepheliumsp. distinctumCyclopsiella trematophoraCymateosphaera sp, Eyrea nebuIosa H, poruum H. tubiferum subsp.H. sp. brevispinum A Achomosphaera sp. Aioro fenestroto ' Ison Alisocysta sensu lii circumstabulataAlterbia sp. A Aptea securigera A. sp, Areosphderidium BaltisphaeridiumdiKtyopIokus Botryococcus Ligospinosum sp, Ceratiopsis speciosaCIeistosphaeridium Comasphaeridiuni anchoriferum cometes Forma-A Forma-B Hystrichosphaeridium astartes -Impletosphaeridius sp, A o-F m 1 c r o p I an k -ton , POLLENITES SPOROMORPHS ft. Indeterminate Microplankton Total MtcropIankton Disacciatrileti P o ly sa c t ci i S t r i a t i ti ti a i rt S Mon oco IpMon ti i Veryhachium Vozzhennikovia sp V. ro tu apertura n d a 5. ramosus . S sp. subsp.ThaI assiphoro reticulatus pelagica T . v e lata Turbiosphaera filosa Spiniferites ramosus SeIenopemphixSenegal nephroides iniuit cum i r asymmet S . esso i S . ternuman 1 5. macmurdoenseS . sp . . S A sp . S, ramosus subsp, granomembranaceus Palambages morulosa Phlhanoperidinium echinatum Spinidinium densispinatum IsabelidiniumI . p e l druggii lu cidum 01igosphaeridium . 0 sp . Operculodinium complex Ophiobolus bergmanni Palaeocystodinium Lapidarisi P. granulotum P . golzowense s p . P , Type ParalecanieI I a I indentata Lejeunecysta L. hyaLina fallax . L sp. Micrhystridium sp. A Pterospermopsis australum I."'spV ” BC‘ I . s p . C KaI Io sp h a e rid iu m c f . cap ulatum aeoperidinium l Pa pyrophorum Leiofusa jurassico P heIodum i spn . i A ro RS S CO CO — S3 IN? IN? — CO — ro ro 3 S § g & c n IN? — — (-> Co ro ro IN? - CO — CO 1° i CO ro s IN? (-* | | ■ ro f—* f—* Ja. . B3 CO CO IN? H-» — - - * — § Si t>— ro — CO — i—» CO rocn ro — — IN? ro ro -b. £3 cn —jOO «- IN? OO cn £8 N COIN? ro cn CO IN? 60 cn CO ro g ro cn IN? IN? fN3 CO OB IN? — — — ■A. ro N- § ro CO CO CO cn -O cn J*. 52? —j — — IN? 55 ro CO OO CO o CO IN?O 88 B rva IS — — aa — —— S S3 K cn C0 — S aa c n s CO ro IN? — rO CO 03 CO CO ro S3 CO Cl? - IN? -te. IN? -J COIN? Si cn H—• S3 — , , . IN? - IN? 88 IN? CO SS —— — FN? £3 8 TO — -ew cn cn -U. E3 — — S3 g S3 R3 cn rv? — — — IN? IN? IN? — ro .u o. — to co CO 8 CO OO — — a? CO 5 - — —— — r» 09 CO -mj IN? — cn — o -u — CO — s CO , , - fv? IN? CO ro £3 IN? a? 8 IN? f—» — cn CO — cn CO IN? 1—X - g B i § »—» »—» cnCO — cn IN? — - S3 CO CD CO ---——-- CO — 1- — r-r-.- J m cn s CO IN? ro g • OD CO CO IN? OO IN? S3 COCO CO OO proplankton, spores, pollen, macerals and mlospore color Index values in the samples of Section S 8 M H T as a ss SS Ri. as si 3S3 S3 as (S s IS as £3 as as SS as st S S 83 LSL E3 £ as SSSSS s R3 83 SS £ ss S3 as £ S is SS 5> S3 3i SS RS £3 SL SS s as Sfl S3 Fo S 3 ss S S3 RS 83 Sfi S. fS E 3S3 S3 Rj 2 S3 S3 SS ES s S3 MonocoIp iMonocoIp t i GranuIonap i GranuIonap t i Ret i tcuIonopi i Ps iIonap i t i Periporit L Periporit ptychotripori ti ptychotripori Stephanocolpiti D i coIp i t i i PoIysacc t i D i sacc iotriI Str j et i at i t i Laevigatomonoleti Loevi gat i Murornati f t p i c u l a i i Monopori • tMonopori i StephanocoIporiti Per i coIp i t i Tr iptychi Tr Tr i por i t i ScuLptatomonoLeti S rtephanopo i t i Amorphous preserved Poorly UeI preserved I Pollenites-Sporites Total M i ospores Scleratoclasts ory preserved Poorly Lie infested LAmorphous preserved I io pr Clr ne Value Index Color Mi ospore Infested oa Mcrl (xldn Inertinite) (Excluding Indeterminate Macerals Total Infested Amorphous Acr i tarchs Infested neemnt Pollenites-Sporitcs Indeterminate TOTAL Inertinite Microforaminifera Di nocysts . SPORITESB. MACERALS RAI CARBON ORGANIC s t s a l c o t s i t o r P Iasts t s a e I o t y h P 2 cn cn C Q ^ CD OO CO CD O -e*. -fc* 3 3 CO CO OO OO GO OO CO CO CO c o cr -o I <-*■■ CO CD cn OO CO CO r o CO rt> ^ » - * r —* * 3 CD cj o 3 MICROPLRNKTON Alisocysta circumtabu I ata Areosphaeridium diktyoplokus BaLtisphaeridium L igospinosum Comasphaeridium cometes Come tod i n i um c-F , white! Def L andrea s p . Eyrea nebulosa Impletosphaeridium sp. A I . s p . C Pa Iaeocystodinium golzowense PaLaeoperidinium pyrophorum Palambages Forma B P . moru L osa cn CO co OO Paralecan iella indentata Erf Spin idin ium densispina turn S . esso i S .. sp . A S . sp . Spin i-fer i tes ramosus subsp. granomembranaceus S. ramosus subsp. reticulatus Vozzhenn i.kovia rotunda CO Erf Erf Indeterm i nate CD rsi Total Microplankton CO s SPOROMORPHS p w 09 09 CO ro -U 09 -J Total Microplankton V ® CO § / ’ / SPOROMORPHS POLLENITES ro S t r i a t i t i tv.-' (-* t CO t-* ro h-» .ro a CO h-» CO CO o s 8 CO Disacciatrileti H* CO 09 CJI SS Ok CO o Polysacci ti D i c o l p i t i t—» l\> 09 .£> ro CO 09 cn CO 8 T r i p t y c h i H* CO sj -J ro [t.-PO CO cn CO CO cn -fck CO CO .u Stephanocolpiti CO ro - P t y c h o t r ipor i t.i (-» ro CO ro M o n o p o r i t i CO H*. CO I-* M Kk CO 09 Ok t-k ro T r i p o r i t i Psilonapiti N9 i-* Granulonapiti SPORITES »-* Z o n a t i CO Tricrassati M ro M M .u CO GO M 1 * ^1 00 H» a 8 A A p i c u l a t i H» •-» 1—k ro CO ro O 09 cn o t—* 1 M W M u r o r n a t i 1 ro 00 CO CO U1 - COCO 09 ro 8 CO L a e v i g a t i 00 IO - cn 32 Ji. ro 1 M 09 s Laevigatomonoleti 1— ►-* cn 1—* ro Sculptatomonoleti 09 i-» 1 I- § fr-I r— 09 CO g 8 3 ro 8 s CO o M Indeterminate PolI enites-Sporites l-» “ ro “ ro cn Ok CO o 8 S N> .& 09 Total Pollenites-Sporites .u 1 si 8 -J HI a cn Ok M R C E R f l L S i-** (—* (Jell p r e s e r v e d i—t 0 0 ^ ro CO 00 09 -j ro Poorly preserved y H ±k )-* CO ro fO CO I n f e s t e d P h y t o e I as is P 7 1 ^ CO A ro cn ro CO cn 1 CO CO -J 8 09 09 CO CO t-* s ro A m o r p h o u s SPORITES Zona t i Tricrassati ro OO ES FS £8 Ap i cuI at i Murornati ro ft ft Laev i gat i ho f3 Laeuigatomonoleti Sculptatomonoleti ft ft Indeterminate Pollen i tes-Sporites ro 2 ft 2 Total PoI Ienites-Sporites MACERALS Llell preserved Poorly preserved Infested PhytocLasts ro on ro cn 03 co co ro Amo rphous Amorphous infested UeIL preserved Poorly preserved Pro t i s tocI as ts Infested ro Sc Ie ra toe I as ts CD M i ospores D i n ocys ts Acr i tarchs Microforamin ifera co I n e r t i n i te Amorphous Infested Indeterminate 03 s CO Total Macerals (Excluding Inertinite) CO Miospore Color Index Value cp cz> CO ro CO - tw cn co CD ft CO cn CD — i CD ft co OO TOTAL ORGANIC CARBON SPOROMOR MICROPLft! granomembrana Indetermi n a te a n Indetermi Impletosphaerid Vozzhenn i.kooia Vozzhenn S .. sp . A . sp .. S I . IsC . p . den ium idin Spin i S esso . S . . sp . S S . S ramosus . subs Sp iniferites iniferites ra Sp P . mo ruL osa ruL P mo . Alisocysta circ' Baltisphaeridiu Palaeocystodini iu Palaeoperidin Palambages a Form I eI i Paralecan Total Total Microplank Areosphaeridiuiti drea s p . an CometodiniumL cfi ef D Eyrea nebulosa C omasphae r i d i um: i d i r omasphae C ro CO & co '** co Table 3. Distribution table showing the percent TOC and the freqU' miospore color index ualues in the samples of Section \ 2. 1 1 SPORITEj MRCERfll POLLENITi SPOROMOI Indeterminate P< In f es ted es f In UeI I preserved I UeI Poorly preserve< Amorphous Ps iIonap i t i t Triporiti i iIonap Ps Granulonapiti A p i c u I a t i i t t a rassa c I u i c r T i p A i Murornati t ga Laeui Laeuigatomonole Sculptatomonole Total Pollenitej D i coIp i t i t i coIp i D Stephanocolpiti ti Ptychotripori 1 Monopori Triptychi DisacciatriIe t i t DisacciatriIe i t Zona Str i at i 11 i at i Str ti Polysacci Total Total Microplani -t*. i—»• 0 3 cn ro ro 0 3 — r o ro ro - CO CO CO s CO — j ' ■■ ■■ '.,v‘ ' J cn ro s — i—»■ 1 1 03 co CO 03 — r o ro 03 § —J -Pw ro CO cn ■—1 8 1 C 3 F 3 TO 0 3 £ 8 CO 1—» £ 3 r o CO CO 2035 1____1 — *. cn CO 83 s — CO cn CD c n ro CO i cn CO £ 8 k oo ro 03 — -Ck H—* ro cn jk. — CO 1 . 1 * 03 CO CO 83 ro 03 03 ro r o ro CO CO — ro r o -tk. » — ro CO CO ro 83 - i CO ro CO COCO 1 r 1 - — CO -U- CO -U. 5i CO cn CO H- S3 r o CO s? 4—» a o 200 ro -C* CO i—* CO cn CO £2 CO 03 cn 03 •—1 ro 1—* TO s ' ^ N X* oo o§ ro '"V CO CO ro oo ro — J*. #— cn CO Tricrassati 1 h- t-k Mro *sl >— M A 05 00 ft A . 05 h- g 8 8 A Apiculcti I M h-» cn ro w ro o 05 cn o H- Murcrrati 1 TJ CD CO CO CO cn a - 05 CO 8 I ft 8 00 Laevigati 1 0 I—• ro M ro 05 s ro ro t-j cn K A ro Laevigatomonoiej ro i—» »— cn t-- ro Scu I ptatomonoLel H* CO ro I-* ro ‘ t-» -0 I-* 05 K t—» jk I—1 CD s § 8 -j ro 8 § CO O Hk Indeterminate PI M i-* I-* A ro l-k CO ro -J cn a 8 8 05 S3 8 CO CO ro a 2 8 8 A S3 8 2 cn A Total Pcllenitej Q H PCERfll J CD - H-* Ue11 p re s e rv e d ! Cl CO cn i-k h-* CO \ p - NJ CO 00 03 -4 ro Poorly preserve:! CO A CO I-* I-* ro A ro CO o M/ CD I n f e s te d \ n Ok. cn a a CO CO A ro cn CO cn cn CO a CO o CO CO *0 ro 05 05 CO co h- o ro Amorphous j w (*“» )-» t—* >-* cn CD A CD cn cn Amorphous infes] t-^ Dell preserved (-» i—* GO Poorly preserve Infested j 05 ro ro ro ScLeratocIasts ] CO A CD M cn 'J CO (S3 CO liiospores M CO 1—* Dinocysts ro Acritarchs Microforam in ifei 0) A cn cn CD A cn i—» CO ro Inertinite ro t-» - CD - A i-* - CO Amorphous Infes- 05 05 03 05 0) 05 05 05 0) 05 CD ro O O s (-» 8 O O O o M O 8 8 Total Macerals (S3 IS) CO ro CO CO ro ro ro PO CO H- ro ro Miospore Color . 1940. 0.259 1530. 0. 491 0.237 . 1810. 6. 0. 578 0.136 2. 738 (- o O 2.887 1.412 Z CO 957 •j ro cnCO TOTAL ORGANIC in - - - f ---- - m --- - lj capulatum " . . ------— ____ s s boLoniensis 1 e I La La indentata I e 1 ft ops ops 1 M I CR O PI L M R N KON T . . . . . p p p p p p s p p s s s Lisocysta cibcumstabaLata ...... s S oon o ti Sample Number Number ftcbomospbaeba sp . ftcbomospbaeba sp ft tispbaebidiam iyospinosumBal L Cera-t C . dar-tmoor-ia . C C . s p . C. p spociosa . s C X . s p . ImpagidiniumC . p macuLatum ImpLetospbaebidium s . X sp. A Come-todlnipm c -F . w b i t e i e t i b w . Cdbebbocysta-F bdbtonensisCome-todlnipm c CycLopsieLLa tbematopboba El y b e a a nebuLosa e b y Cymatiospbaeba El sp. Hystbicbospbaebidiam p a b o o Hystbicbospbaebidiam b a p H. -tubi-Febum sabsp. bbeoispinumH. -tubi-Febum Kal lospbaebidium c -F ina lospbaebidium-F Kal L c a Lejeunecysta y b PaLaeocystodin i u m a u s t b a L i n u m u n i L a b t s OpebCuLodirtium bergmanniiu m a u PaLaeocystodini P. P. yoLzowense P Opbiobolus Lapidabis Palaeopebidin i u m m pybop.bobum u Palaeopebidini Pa I ambages mobulosa I Pa Panaleoan PbeLodinium sp. Spinidinium A densispinatum S. S. lantebnum Indetebminate S S T anyospbaeb i d i um xan th i opyx I das I opyx i th um xan Spini-Febites i bamosus d anyospbaebi T S S S Tbiyonopyxidia y i n e LLa e n Tbiyonopyxidia i y — oo CO CO , — — .— - . —* n o c n r v o — c n g § — — s Cl . oo c n — O r o --- j r o —— CO C-O PS — & = ! — C _ O oo gp CO j — O 0 5 c n ro __ ,— j _ C — — C r o S3 r v o , , - £S .. 3 oo CD J as no cn __ S — on oo , — CO n«o c n a s ro O oo S oo cjn • oo cjn j - — cn — >— — ■ CO — oo on — C bn o o —* CO ■iv c n c n r s o— r > o Table 4. Distribution table showing the percent TOC and the frequency counts of mic in the samples of Sections 15 and IB. y ! ’ ! A / \ / \ • • Sporites & Phy toe I asts I toe Phy Protistoclasts Sporites & SPORITES MRCERALS POLLENITES p i t i t i p I SPOROMORPHS p i t i t i p I rphou's Indeterminate Indeterminate / \ Total Pollenites Total Total microplankton Total Di sacc i a t r iIe t i t iIe r i et t a L i i sacc tr Di i sacc i t Di i PoIysacc i Monoco tych p i Tr Di co Di i i t t i i por StephanocoIp i Ptychotr i i t ti t Stephanocolpori i opor i por Mon i Tr Granulonapiti Indeterminate Pollenites Ps iI on ap i t i t i i t ap i on Stephanopor iI Ps Infested Ap i cuI a t i t a i cuI t a i rn Ap ro Mu Laeu i ga t i t ga i Laeu Laeuigatomonoleti Infested ScuIptatomonoIeti UeI I preserved I UeI Poorly preserved Amo Amorphous infested UelI UelI preserued Poorly preserued asts IeratocI Sc Dinocusts Miospores Miospores 8 8 cn ro TO — 1—<" ro 1—k -th. h—* 8 8 £ ro CO M 03 ro ro IO i—» l—k CO 4^. (—* OO CO g ro » *—* J 8 3 § 35 ro 8 l—t »—* CO - -Ch. 1—k cn ro j—» g cn 03 ►—* 1—* — 03i— CO -Ch. 03 CO . • 3 CO -Ch to 8? oo l—l -th. CD ro -- ro CO 00 CO s ro CO CO 03 -Ch. g S h—■■ 8 PS 03 -Ch 8 CO A ro h—» cn ro —j 03 CO - 8 8 cn PS 8 CO -4 ro -Ch. micropI ankton, spores, pollen, macerals and miospore color index values 0 (I) ID P 0 P P id ID p 0 L CD P P 0 0 U 0 L a — i 0 c 0 ipH 01 0 p C 0 (D E p H L 0 0 0 0 P 01 P P c ® ;r-t £ 0 0 '*■* 0 L 1 L p 0 0 V > iH (L c J a -J X c in 0 U 0 0 X V 0 0 ill c P P 0 to 0 L p ^ H ifi ■H ® 0 Q. a 0 ® 0 P p L p 0 0 P 0 0 L ,p 0 P 0 0 ■r-t 0 L p -< 0 0 L a »H c P C 0 0 c 0 - — i 0 L 0 0 0 L 0 L 0 ■p 0 a 0 0 P £1 E c 0 ® 0 0 0 iH u u p a iiH (5 ■H o irt L (0 (0 0) L u a p £ 0 L 0 P 0 a c p -p E 0 a o J 0 0 a o irt 0 c P c L c o o 0 0 L a ® 0 0 L 0 0 a oi o 0 0 0 L 0 c j 0) 01 P 0 01 P I £ a oi p 0 P £ £ £ Q 0 £ o 3 if, iiH 0 P -■ (11 Cl £1 - ® 0 0 a a 0 a o Cl Cl-J c 5 0 -» ai o L 0 L L J L 0 0 p c 0 ,h ® 01 ® c 0 - o 0 0 3 o 0 P 0 0 -> 0 P p 0 ,« L p p p 0 L p D) L OOU c 0 0 c E E ® o c 0 '« I Q b U)1 (/I T b d) U) CL 0 J J U) H f- CL h 1 4 3 0,134 501 4 11 2 1 6 335 JHH84 "es, pollen, macerals and miospore color index values C&C - -- ---- CROPLflNKTON anuiti ^ I . u i ctor i i ctor i u . I ImpIetosphaeridium B . sp . I spA . C . I . sp Lejeunecysta sp. OpercuIodiniumi Qphiobolus bergmanni lapidaris 0 1igosphaeridium 0 complex Micrhystridium spA . D . D . s pA . Impagidiniun maculatum Deflandrea antarctica Type I Forma-B H. tubiferuni s u b s pbreuispinum . A . H sp , D. D. oebisfeldensis sensu D . gniformisD . cy D, D, antarctica Type II Cometodiniurn c fwhitei . Cyclopsiella trematophora Botryococcus sp.Chytroeisphaeridia explanata D . . . sp D Hystrichosphaeridium parvum H . . sp . H Cymateosphaera sp. Comasphaeridium cometes Diconodinium cristatumD. multispinum Eyrea nebulosa Forma-A Aptea securigera Aiora fenestrata sensu UiIson Areosphaeridium BaItisphaeridium diktyoplokus ligospinosum A L terb i a a s pA . i terb L A 3 3 0--0 z in C Q _ — S e c t i o n ^ D ro to —t ro — — — C — — ro — to 8512 — i -fck. CO -fc*. 1—k — s ro - CO «— cn CD — 8510 . . CO — — ro 8509 ro cn —j ro s* — t ss ro — ro CO 8508 CD t—» SS I—» 8507 03 —- ro ro cn ~ ro ro 03 CD — 09 8506 CO — 8505 -b. ' CO ro i—» ro CO 03 S3 CO _£* CO cn CD cS — ro |M CO ro ro ro — _fik. CO roi—‘ _E* 8 cn CO CD CO 1—» o — —j — cn ro ~ 03 — cn CO cd ro —‘ CO — co j*. si— s* i—»■ CO — CO ro CO cn o — 1 »- INS ro S3 03 ro S — —— 8500 X Table 5. Distribution table showing the percent TOC and the frequency counts of mic I . SP . C Lejeunecysta sp . Micrhystridium sp . A 0 I igosphaeridium complex Operculodinium bergraann i i Ophiobolus lapidaris Pa Iaeoperidinium pyrophorum Palambages morulosa P . Type I Eg S3 ParalecanielLa indentata PheIod i n i um s p . A Phthanoperidin ium echinatum Senegalinium asymmetricum Spinidinium densispinatum S . esso i S. macnturdoense S . sp . Spiniferites ramosus S. ramosus subsp. multibreois S. ramosus subsp. reticulatus S . sp . Thalassiphora pelagica Vozzhennikooia apertura s V . rotunda S3 83 SI fS 83 Indeterminate Microplankton SS S3 S S3 Total Microplankton SPOROMORPHS POLLENITES S t r i a t i t i S3 & <£n S3 Disacciatrileti PoIysacc i t i Tr i ptych i S3 88 S tephanocolpi ti Ptychotripori ti Stephanocolpori ti Tri por i ti 2 ± Stephanoporiti Per i por i t i IondDi ti PhytoeIasts Protistoclasts MACERALS SPORITES te j j TOTAL ORGANIC CARBON ORGANIC TOTAL Infested Inert i n n i Inert Infested Amorphous Infested Indeterminate Total Macerals CExcluding Inertinite) Miospore Color Index Value Indeterminate Pollen i tes-Sporites Indeterminatei Pollen LJe I I p reserved p I I LJe Poorly preserved LJe I L preservedL I LJe Poorly preserved M i ospo res res ospo Scleratoclasts i M nocysts i D tarchs i Acr Microforaminifera Ap i cu L at i i at L cu i Ap Amorphous Amorphous infested Murornat i i Murornat i gat Laeui Total Total Pollenites-Sporites Ps i L on ap i t i i i t t i i ap por on i Per L i i t Ps i Lonap Granu Tr i crassat i crassat i Tr Laevigatomonoleti 5 tephanocolpit i i tephanocolpit 5 i ti Ptychotriporit i ti Stephanocolpori por i Tr ti Stephanopori CO 0 9 CD CO 1— * — — CO - Jk 0 9 cn co ro ro -Ck. 0.201 s - CO S s CO cn ro ro — cn S3 — 58 0.263 1—» cn -fek. CO j CD ro ro ro ES ro 09 CO - co — oo ■— CO ro CO ro CO cn 1.167 •N-" s CO Jk. 1—* _tk. ■«J ro — cn CO oo _tk —— OO E3 09 09 -6* 0.351 cn CO ro — ro CO cn CO — CO S3 - ros CO ro cn cn s • • I—* CO CO •^j _th C£> J*. § —J- CD 09 CD ro CO cn ro ss 09 8 ... » -- S3 H- oo 09 ro 1 CO -Ck cn 09 - _- CO 1.054 1—• ro CO ro CO & oo 09 CD CO CD -fck. ro 1—“ 1—k CD EH 09 CO ro -—i ro — isd —j 0.116 CD SB Co oo ro t~->. -tk> — as - -tk. ro 1—k 8S CD CD s3 CO & CO 09 CO fs _6k ro •—* CO cn - ro oo 88 oo cn ro 8 ro i—‘ ro 09 CD CO CO ro (-* CO i—‘ — — 1—* S3 S CO cn H-* 0.775 *—* SS -^+-, - ■-7^y+--S,r d 09 ro ss — ro ro ro co CO ro CO cn — ~ CO ro 3 ro ro CO CO CO 0.662 > / - s » » ' v --- CD a > — t-» cn co _Ek. _fch. s i ro — S ££ — ictions 17, IB and 19. C O O O C O COQOCOOOOOCOOOCOCOCOCOCOO0COGOCOCOCO -Ck -U 4^. -£^ .£». -few _£*. _£». -fck. _c*. -C** -fc^ -fc*. _t>. -t*. -±w — -j — i -t^ j*. c n c n c n c n *—J c n — j c n c n UJ <+ co ro co cn j *. 03 ^!k c n 03 —-J CD CO CD fN3 1—* CO —O OO -fc* CD CH 03 M I CROPLANKTON X ------X Def Landrea cygniformis X ------X Lejeunecysta fallax X ------X L. hyalina X X SeIenopemphix nephroides ------X Forma A ------X Lejeunecysta sp . ------X Hystrichosphaeridium astartes ------X Vozzhenn ikooi a apertura ------X Palambages Type I ------X Deflandrea sp. ------X Eyrea nebulosa ------X Impletosphaeridium sp. A ------X I . s p , ------X Operculodinium bergmannii ------X Ophlobolus lapidaris ------X Palaeoperidinium pyrophorum ------X Palambages morulosa ------X ParaI canieI I a indentata ------X Spinidinium essoi ------X Vozzhenn ikouia rotunda Xr------X Aptea securigera x ------X Diconodin ium cristatum ------X D. multispinum X Achomosphaera sp. X Pa Iaeocystodinium sp. X------X Deflandrea oebisfeldensis > sensu C&.C Achdmosphaera sp. X Palaeocystod 1 nium sp. X X Deflandrea oebisfeldensis > sensu C&lC Cometod 1 nium c f . white! Mi crhystr idium sp. A Phelodinium s p . A Spinidinium macmurdoense S . s p . A Sp i n i -f e r i tes sp . A Iterb i a s p . A Isabelidinium pellucidum CycIonepheIium distinctum Phthanoperidin ium echinatum Hystrichosphaeridium paroum CycI opsieI I a trematophora Ap tea s p . ImpIetosphaeridium sp . C Isabelidinium druggii Deflandrea sp. A Cribroperidin ium s p . C y m a t 1 osphaera sp. Cleistosphaeridium anchoriferum Spiniferites ramosus subsp. reticulatus 01igosphaeridium complex Spinidinium lanternum Botryococcus sp. Deflandrea antarctica Type I Areosphaeridium* diktyoplokus Sp i n i d i n i um s p . Comasphaeridium cometes Veryhachium sp. Ba I tisphaeridium ligospinosum Leiofusa .jurassica Deflandrea antarctica Type II ret 1 cut atus -X 01igosphaeridium complex Spinidinium lanternum X Botryococcus sp. X Deflandrea antarctica Type I X Areosphaeridlum'diktyoplokus X Spinidinium sp. t X Comasphaeridium cometes Veryhachium sp. Baliisphaeridium ligospinosum Leiofuso jurassica Deflandrea antarctica Type II X Hystrichosphaeridium s p . A X Spiniferites ramosus X Kal losphaeridium c f . capulatum X Aiora fenestrata sensu UiIson Spiniferites ramosus subsp. granomembranaceus Thalassiphora uelata Turbiosphaera filosum Thalassiphora pelagica Hystrichosphaeridium tubiferum subsp. breuispin ium Deflandrea cf. phosphor!tica Impagidinium sp, 01igosphaeridium sp. Alisocysta circumtabu I ata Senegalinium asymmetricum Spinidinium densispi natum Impagidinium dispertitum Palaeocystodinium granulatum Ceratiopsis speciosa Forma B PaLaeocystodinium golzowense S a m p l e to to - t o o to j i o o o e - a a o o o a o o . — • u o Table 6, Range chart o-f dinocyst species in Section 3, Seymour Islaj (Arranged by the stratigraphic top of each species, ) , cn 2 in M ft oo oo CO oo oo oo CO c o -t*. -C&. J*. 3 3 cu r> OO oo oo GO CO OO CO oo CO CO CO CO CO CT-o I c+" ro CO 0 3 cn CO CO l\3 CO H* *-■ ft i- Ui o ™s ft 3 MICROPLRNKTON X -X Comasphaeridium cometes X- X ImpIetosphaeridium sp. C X -X Spinidinium essoi X -X Spin iferi tes ramosus s u b s p . g ran omemb ran aceus X -X Eyrea nebulosa X -X Spinidinium densispinaturn -X Paralecan iella indentata X -X ImpIetosphaeridium s p . A X -X Pa Iaeoperidinium pyrophorum X- -X DefIandrea sp. X—-X Alisocysta circumtabuLata X X Spiniferites ramosus subsp. > reticula tus X X Pa Iaeocystodinium golzowense Spinidinium densispinatum Para IecanieI I a indentata ImpIetosphaeridium s p . A PaLaeoperidinium pyrophorum DefIandrea sp. AL isocysta circumtabu Iata Spiniferites ramosus subsp. reticula tus Palaeocystodin ium golzowense Cometodinium c f . whitei Palambages morulosa Vozzhennikooia rotunda Areosphaeridium diktyoplokus Palambages Forma B Spinidinium sp. A BaItisphaeridium ligospinosum n a ID o& ** X- -X ImpIetosphaer i d| V 3 o in X- ■# Palaeoperidin U n a & Q -X 0 0 Deflandrea sp, J3 (0 ^ T5 m x— x AL isocysta circ| ® I f) H» M> U Spiniferites rc ©' x— x ID reticulatus • in w ® X—X Baltisphaeridiui c I x-x Spinidinium sp. z CD Impletosphaeridium sp, C Spinidinium I on te rnum te Spinidinium on I Spiniferites ramosus ta a um rcumtabuIc fwhitei Alisocysta , i i n c i tod Come Cymateosphaera sp, Spinidinium densispinatum Spiniferites sp, Palaeocystodinium sp, Hysirichosphaeridium parvum Achomosphaera sp, Ka11osphaeridium cfcapulatumOpercuIodinium bergmannii Palaeocystodinium golzowense Paralecaniella indenta Section X-X Table S Range c P a r -t o -P ciinocyst spec i e s in Sec-tion 15 and IS C f^n ranged fc> sd -t In e s-tra-ti graphic -top o -f e a c In species. ) o rt> e+ X X PaIaeocysiodinium golzowense Q — n o a- 3 X X Paralecan iello indenta in h- ■o cn © x X Spinidinium densispinatum n q >-*■ 3 ID CL X X Spiniferites sp. in x-x Pa Iaeocystodinium s p . if t a> x x Spinidinium sp. cc X X Impagidinium maculatum X X Pa Iaeocystodinium australinum in X X Imp Ietosphaeridium sp . A X X Ophiobolus lapidaris X X Ceratiopsis boloniensis o X X Cerebrocysta bartonensis o X X Eyrea nebulosa X X Palaeoperidinium pyrophorum X X Spinidinium s p . A x-x Lejeunecysta hyalina x x Palambages morulosa x x Trigonopyxidia ginella X -X Baltisphaeridium Iigospinosum X -X Ceratiopsis dartmooria X ■X Cyclopsiella trematophora X- -X Imp Ietosphaer i d i um sp. A X- -X Ophiobolus lapidaris X- -X Ceratiopsis boloniensis X- -X Cerebrocysta bartonensis X- -X Eyrea nebulosa X- -X PaLaeoper id in ium pyrophorum X- -X Spinidinium sp, A x-x Lejeunecysta byalina x-x PaLambages morulosa x^< Trigonopyxidia ginella x- -X Baltisphaeridium ligospinosum -X Ceratiopsis dartmooria x- -X Cyclopsiella trematophora X X Ceratiopsis speciosa x-x C, sp, x - x ' Hystrichosphaeridiufn tubiferum < subsp, breuispinium x * Phelodinium sp. A x-x Tanyosphaeridium xanthiopyxides 00 Section 00 00 00 CO 00 00 CO 00 00 CO oi tn CJ1 01 01 01 01 01 01 01 o o 0 o o o o CO ji. 01 0) CO CO ro MICROPLfiNKTON X— X Botryococcus sp, X—X Forma-A x— x Spinidinium densispinaturn -----X Cymatiosphaera sp, -----X DefLandrea sp, A -----X Impagidinium uictorianum -----X Micrhystridium sp. A -----X Operculodinium bergmannii X------X Hystrichosphaeridium sp, X------X Spiniferites sp, X- - x Impagidinium maculatum X- Palaeoperidinium pyrophorum Senegalinium asymmetricum Chytroeisphaeridia explanata DefLandrea sp, Hystrichosphaeridium paruum Pa ra L ecan i e L L a indentata Spinidinium essoi Baltisphaeridium ligospinosum Cyclopsiella trematophora Eyrea nebulosa Phelodinium sp, A Phthanoperidinium echinatum Spinidinium sp, -X Vozzhennikouia rotunda X- -X V, apertura ----- ;------X Spinidinium sp. 7V Vozzhennikovia rotunda v A VA v, apertura V A AV Areosphaeridium diktyoplokus )( VA Imp Ietosphaer id i um sp, A X------X I . sp. B Palambages morulosa X- Come tod i n i um c f , whitei Aptea securigera X- Diconodinium multispinum Spinidinium macmurdoense Deflandrea cygniformis D. oebisfeldensis sensu C&C Diconodinium cristatum ALterbia sp. A X- 01igosphaeridium complex X- Palambages Type I X- Spiniferites ramosus subsp. reticula tus x- -X Ophiobolus lapidaris Comasphaeridium cometes Spiniferites ramosus subsp, multibreuis -X Impletosphaeridium sp, C X- -X Deflandrea antarctica Type I x- Hystrichosphaeridium sp. A X- -X H. tubiferum subsp, brevispinum [ x - -X Deflandrea antarctica Type II Cyclonephelium distinctum Forma-B Spiniferites ramosus Aiora fenestrata sensu U iI son IX- -X Lejeunecysta sp. /\ Ix- -X Thalassiphora pelagica- MICROPLANKTON V. V. aper S e c t i on S ei c t ■X Cymatiosphaera■X s p . X Deflandrea s pA . X Chytroeisphaeridia explan X Deflandrea s p . X Hystrichosphaeridium parv X Eyrea nebulosa -X , Botryococcus-X sp Forma-A ■X Spinidinium -X densispinatum; X uictorianumium Impagidin X Micrhystridium s pA . i X Operculodiniumi bergmann X Hystrichosphaeridium sp.X Spiniferites s p . X maculatum ium Impagidin IaeoperidiniumX pyrophor Pa X Senegalinium asymmetricum X Paralecaniella indentata Xinidinium essoi Sp X Baltisphaeridium ligospin X Cyclopsiella treraatophora X Phelodinium s pA . X echinatuium Phthanoperidin X Spinidinium s p . X Vozzhennikouia rotunda x X X X X X X X CD X X X X CO X X- X- X x- X- X X Table 9. Range chart of dinocyst species in Sections 17, 18 and (Arranged by the stratigraphic top of each species.) in o q X X Spinidinium s p . Q 3 X X VozzhenniKouia rotunda a X -X V . aper tura -X U 3 Areosphaeridium diktyoploj X -X Impletosphaeridium s p . A X I . sp . B X X Palambages morulosa X X Cometodinium c f . white! X—X Aptea securigera X X Diconodinium multispinum X Spinidinium macmurdoense X X Deflandrea cygniformis X X D. oebisfeldensis sensu G3 X X Diconodinium cristatum X X ALterbia sp. A X X 01igosphaeridium complex X X Palambages Type I X X Spiniferites ramosus s u b s ] re t i cuI a tus X Ophiobolus Lapidaris X X Comasphaeridium cometes X—X Spiniferites ramosus subsj multibreuis X Impletosphaeridium sp. C X X Deflandrea antarctica Typ;< X X Hystrichosphaeridium sp. XX H. tubiferum subsp. breui X X Deflandrea antarctica Typ< Cyc I on ephe I i um distincturh Forma-B Spiniferites ramosus Aiora fenestrata sensu LJi Lejeunecysta sp. ThaI assiphora pelagica 0> CO CO CO CO CO CO CO CO OO CO GO CO CO CO 00 OO CO GO OO OO CO CO -fcik -tu. _fc». -Ck. -fc*. -fc- -fc*. -tk. -tw _fc*. -C&. -fc*. _&*. -ta> -t*- -Ew _£». -t>- — 1 cji 4 c n cji cct c o r o co c n _c^ cri _tw c n c n — i c n c o C 3 r o 1— * co—1 00 co cn 0 5 MICROPLRNKTON Ceratiopsis speciosa Forma-B Polaeocystodin ium golzowense P. g ran u I a turn Spin idin ium densispinatum Oligosphaeridium sp. A Turbiosphaera fiIosa Spin iferi tes ramosus subsp. granomembranaceus -X Hystrichosphaeridium sp. X Baltisphaeridium ligospinosum X Leiofusa jurassica -X Areosphaeridium diktyop I ok us X Sp i n 1d i n1um sp x Def Landrea aniarctica Type I -x OL igosphaeridium complex X Spin idinium lanternum X ImpIetosphaeridium s p . C X Isabelidinium druggil X Cyclopsiella trematophora X Micrhystridium sp, A X Phelodinium s p . A X Spin idin ium macmurdoense X S . sp . A ± 1 X Spin i-feri tes sp . X Deflandrea s p . X Eyrea nebulosa i m o i S . sp.A -X Spiniferites sp. X Def L andrea s p . X Eyrea nebulosa X ImpLetosphaeridium sp. X I . sp . X Operculodin ium bergmannii X Ophiobolus Lapidaris X Palaeoperidin ium pyrophorum X PaLambages morulosa X Paralecanlei la indentata X Sp in id in ium essoi X Vozzhenn ikouia rotunda Aiora fenestrato sensu Uilson -X Veryhachium sp. Comasphaeridium cometes X Spiniferites ramosus subsp. reticulatus X Cymatiosphaera sp. X Aptea s p . • X Hystrichosphaeridium paruum X Cometodin ium cf . white! X PterospermeLLa austraIiensis X Diconodinium multispinum X PaLambages Type I X Phthanoperidinium echinatum Impagidinium dispertitum Def Landrea c f . phosphoritica Impagidinium s p . X Def Landrea antarctica Type II X Hystrichosphaeridium astartes X Vozzhenn ikouia apertura ThaLassiphora peLagica ALisocysta circumtabuLata SenegaL in ium asymmetricum X KaLLosphaeridium c f . capuLatum x Phthanoperid inium echinatum Impagidinium disperti turn DefLandrea c f . phosphoritica Impagidinium s p . -x Deflandrea antarctica Type II x Hystrichosphaeridium astartes x Vozzhennikouia apertura Thalassiphora pelagica Alisocysta circumtabuI ata Senegalinium asymmetricum -x KaLLosphaeridium c f . capulatum x Lejeunecysta sp. Hysirichosphaeridium tubiferum subsp. breoispinum Thalassiphora velata -x Spiniferites ramosus x Forma-A x Cribroperidinium sp. x X CycLonepheIium distinctum. X X Aptea securigera X X Diconodin ium cristatum X X Botryococcus sp. X X Deflandrea oebisfeldensis sensu C8.C XX CIeistosphaeridium anchoriferum X-- X Alterbia sp. A X Deflandrea s p . A XX Isabelidin ium pellucidum X— X Def landrea cygn iformis X-- X Lejeunecysta fallax X X L . hyaIina X X Se I enopemphix nephroides x Achomosphaera sp. X Palaeocystodin ium s p . Table 10. Range chart of dinocyst species in Section 3, Seymour Isla| (Arranged by the stratigraphic base of each species.) 3) E Q l a O' O O CL O •- V X X A X / X X X \/ \/ \/ \/ X /\ A A s\ X X \ f \/ V X/s X s \ XA A A X X }\AAA f \/ \/ X X XA A XXX /\ Seymour Island, Antarctica lecies. ) JHW83 > z u i 01 t->- (D COCO COOOOOCO CO CO OO OO CO OO C Q r\j n -P x -E x -E x -fcx -Ex -fcx -fcx -E x - r x -E x 3 3 f r+- CO CO CO CO CO OO CO CO CO COCOCOCO O’ ~o IN3 C O 0 3 c n •— 1 COCO CD POCO -E x 4-1 i- *' CT> <— (jj o 3 M I CROPLfiNKTON Spin idin ium sp. Baltisphaeridium ligospinosum -X Vozzhennikooia rotunda X ParaleconielI a indentata X X Spinidinium sp. A X ---- X PaLambages morulosa X- X Spinidinium densispinatum X X Deflandrea sp. X X PaLambages Forma B X ---- X Eyrea nebulosa X X Areosphaeridium diktyoplokus X X Comeiodin ium cf . whitei X ---- X Pa Iaeocystodinium golzowense > X- X ImpLetosphaeridium s p . A Spinidinium densispina turn Deflandrea sp. PaLambages Forma B Eyrea nebulosa Areosphaeridium diktyoplokus Cometodinium c f . whitei Pa Iaeocystodinium golzowense ImpIetosphaeridium s p . A Pa Iaeoperidinium pyrophorum Spiniferites ramosus subsp. granomembranaceus Alisocysta circum tabuLata Spiniferites ramosus subsp. ret i cuIatus Impletosphaerid1um s p . C Spinidinium essoi Comasphaeridium cometes MICROPLflN/ Imp Ietosphaer i d i d Ietosphaeri Imp Pa Iaeocystod i n i u u i n Iaeocystodi Pa Palambages Forma;; Areosphaeridium Comeiodinium cf, Baltisphaeridiuiii; Baltisphaeridiuiii; Paralecaniella i Spinidinium sp." Vozzhennikovia r Spinidinium sp, Deflandrea sp, Pa I ambages I morukPa X| Eyrea X| nebulosa ■X| Spin idin ium ium dens' idin Spin ■X| -X -X A CD CO -X A CD ro -X -X 05A CO CO CD O COAA CO CO CD CD 00 A 00 CO A CO CO CO A CO CO CO a AACO CO CO CO A CO / AACO r\> CO CO A CO Tabl e 11. Range cb a r -t o-f dinocys-t species in Section 12-13, Seym (Arranged by the strat 1 graphi c base o -F o a c d species. ) / 0 7>" Spinidin'iul J (I)n n - (D D e f l a n d r e a sp, a ci Q in „ ® 3 X—X Palambages Form! % X- XI Eyrea nebulosa i Q® *f n r X—X Areosphaeridiuitill If) 0 ^ 9 IU Cometodin ium cf ; n i X—X w P (II u 0 ‘ X X Pa I aeocys tod i ni'i « in 0 X|Spiniferites rami Q 3 .granomembranacl a ]> A l i s o c y s t a circtfl 3 X—X d* Q 3 X—X Spiniferites ram| n d- reticulatus n Q X- X Imp Ietosphaer i d i| X- Spinidinium essol <_ i X X Co m a s p h a e r i d i u m £ «J des 1 MICROPLRNKT ON MICROPLRNKT n i d i n i um sp. A um sp. i n i d i n 1 subsp. subsp. breoispinum Sp Eyrea Eyrea nebulosa Palaeoperidinium Palaeoperidinium pyrophorum CyclopsieLla CyclopsieLla trematophora Ceratiopsis bolonlensis Cerebrocysta bartonensis Phelodinium sp. Phelodinium sp. A Tanyosphaeridium xanthiopyx Ceratiopsis speciosa igospinosum tisphaeridium I Bal Ceratiopsis dartmoorla Ceratiopsis Ceratiopsis sp Hystrichosphaeridium tubiferum X—X > ^ - X Table IE. Range chart of dinocyst species in Section 15 and 16, (Arranged by the stratigraphic base of each species,) ii um s p . sum p . A i um cf. um cf. capulatum 1 nlum nlum golzowense i d um um bergmann 1 i n i ferltes ferltes sp, i n i Impletosphaendium sp. C ImpIetosphaerld Spinidinium sp. A Spinidinium sp. Cymateosphaera sp. Iosphaer KaI Iaeocystod Pa Palaeoperidin ium purophorum ium Palaeoperidin Cometodinium cf. whitei OpercuIod a indentata I ParaIecanieI Sp Spinidinium denslsplna turn Spinidinium denslsplna Ophtobolus lapidaris Achomosphaera s p , ata I Alisocysta clrcumtabu Lejeunecysta Lejeunecysta hyalina Palambages Palambages morulosa X nd 16, Seymour Island, Antarctica, Impagidiniurn maculatum Palaeocystodinium austrahnum Spimferites ramosus Impletosphaeridium sp, A Spinidinium sp Hystrichosphaeridium parvum Spinidiniumternum an I Qphiobolus lapidaris Achomosphaera sp, Alisocysta circumtabulata Lejeunecysta hyalina Palambages moruIosa Trigonopyxidia ginella Spinidiniumturn spina 1 dens S p i n i f e n t e s sp J H W 7 7 CO Sect i on 2 cn CO co 0 3 CO CO 03 CO co 03 0 3 co CO oo C Q cn cn cn cn cn cn cn cn cn cn cn cn cn 3 3 CD CD o CD o CTO K3 co cn CJ> 03 co (D # - "5 CD MICROPLfiNKTON -X Aiora fenestrata sensu U iI son -X Lejeunecysta s p . -X Thalassiphora pelagica -X Forma-B -X Deflandrea antarctica Type II -X Hystrichosphaeridium sp . A -x Deflandrea antarctica Type I -x Spinidinium macmurdoense ■X Ophiobolus lapidaris X Areosphaeridium diktypplokus X Baltisphaeridium ligospinosum X Impletosphaeridium sp. A X I . sp . B X Cyclopsiella trematophora X Eyrea nebulosa X Phelodinium s p , A X Phthan operidinium echinatum X Spinidinium sp. X Spiniferites sp. X Vozzhenn ikovia rotunda X X Spiniferites ramosus X---- X Impletosphaeridium s p . C X---- X Spiniferites ramosus subsp. reticulatus — X Diconodinium multispinum X---- X DefI and rea sp. x - x Impletosphaeridium s p . C X X Spiniferites ramosus subsp. reticulatus J*- X Diconodinium multispinum X X DefI and rea s p . X Hystrichosphaeridium paroum X X Paralecan iella indentata X X Spinidinium essoi X -X Hystrichosphaeridium tubiferum subsp. breuispinum X -X 01igosphaeridium complex X -X Palambages Type I X X Chytroeisphaeridia explanata X— X CycIonepheIium distinctum X---- -X Alterbia sp. A X -X Cometodin ium cf . whitei X X Vozzhennikouia apertura X X Senegalinium asymmetricum X X PaLaeoper idinium pyro'phorum X—X Comasphaeridium cometes X—X Spiniferites ramosus subsp. multibrevis X X Impagidinium maculatum X X Deflandrea cygniformis X X D, oebisfeI densis sensu C&C X X Diconodinium cristatum X X Aptea securigera X X Palambages morulosa X X Hystrichosphaeridium s p . X X Cymatiosphaera s p . X X Deflandrea s p . A X X Impagidinium victorianum X X Micrhystridium s p . A X X Operculodinium bergmannii X X Botryococcus s p . C l CS sp i n a turn a n i sp "1 mu Itibreuis mu subsp. subsp. breuispinum Impagidinium victorianum Impagidinium OpercuIodinium bergmann i i i OpercuIodinium bergmann Botryococcus s p . Impagidinium maculatum Impagidinium Cymatiosphaera Cymatiosphaera s p . A Deflandrea s p . Micrhystridium A s p . s Spinidinium den Diconodinium Diconodinium cristatum Aptea securigera Palambages Palambages morulosa Hystrichosphaeridium s p . Forma-A Senegal in ium asymmetricum ium in Senegal D. oeb i sf e I dens i s s'ensu s s'ensu i dens I e sf i oeb D. Deflandrea Deflandrea cygniformis Cometodinium c f . Cometodinium cwhitei f . Comasphaeridium Comasphaeridium cometes Spiniferites subsp. ramosus ParalecanieLla ParalecanieLla indentata Chytroeisphaeridia Chytroeisphaeridia explanata onepheIium distinctum CycI apertura ikovia Vozzhenn Hystrichosphaeridium Hystrichosphaeridium tubiferum Palambages Palambages Type.I A a s p . i Iterb A Palaeoperidinium pyrophorum Spinidinium Spinidinium essoi 01igosphaeridium 01igosphaeridium complex Hystrichosphoeridium Hystrichosphoeridium parvum V A V A V A A V X X X X -X X X -X - x -X -X XXX -X V* A A V A AAA \s X—XX X X -X X X X X X X X X X X—X X X ---- X X—XX X X X X JHW78 MICROPLANKTON subsp. subsp. reticulatus Vozzhennikovia Vozzhennikovia rotunda Impletosphaeridium sC p . Diconodinium Diconodinium multispinum Deflandrea sp I . B sI p . . Impletosphaeridium s p . Impletosphaeridium sA p . Spiniferites ramosus Spiniferites Spiniferites ramosus Phelodin ium s p . sA pium . Phelodin Spinidinium sp. Spiniferites Spiniferites sp. Hystrichosphaeridium sp Areosphaeridium Areosphaeridium diktyoplof BaItisphaeridium ligospin* Phthanoperidinium echinati Cyclopsiella Cyclopsiella trematophora Eyrea nebulosa Deflandrea antarctica T y p« y Deflandrea antarctica T Deflandrea Deflandrea antarctica Typ< Spinidinium macmurdoense Ophiobolus lapidaris Lejeunecysta Lejeunecysta s p . Thalassiphora pelagica Forma-B Aiora fenestrafa sensu LI I Aiora fenestrafa sensu LI Section X PO X <£> X X X x -X 0 5 -X CO X X X X X X X X X X x X x X X X x x X x X X Table 13. Range chart of dinocyst species in Sections 17, 18 an (Arranged by the stratigraphic base of each species.) i n i um um sp i n i subsp. reticulatus subsp. subsp. breuispinum subsp. multibreuis Diconodinium cristatum Diconodinium morulosa Palambages Senegal in ium asymmetricum ium in Senegal securigera Aptea Impletosphaeridium sp. C sp. Impletosphaeridium Deflandrea cygniformis ( Deflandrea sensu densis oebisfeI D. Hystrichosphaeridium tubi Hystrichosphaeridium Palambages Type I Type Palambages whitei cf. todiniurn Come PaLaeoperidinium pyrophori PaLaeoperidinium cometes Comasphaeridium subsi ramosus Spiniferites Spiniferites ramosus Spiniferites ramosus Spiniferites distinctum onepheIium CycI 01 igosphaeridium complex igosphaeridium 01 Diconodinium multispinum Diconodinium A . sp a i rb te L A X Hystrichosphaeridium X sp. Hystrichosphaeridium X sp. Cymatiosphaera XA sp. Deflandrea X victorianum Impagidinium X maculatum Impagidinium X sp. Spiniferites rotunda iKovia X Vozzhenn parui X Hystrichosphaeridium X indentata Paralecaniella X essoi Spinidinium X Chytroeisphaeridia exp I ani I X exp Chytroeisphaeridia X sp. Deflandrea X apertura Vozzhennikooia X X X X X X -X X X X X X X -X X X X X X ------X X—XX X ------x— X— X X— x- X X X X x tions 17, 18 and 19, each spec i es.) subs! subsp. subsp. breuispinum mu Itibrevis mu Impagidinium victorianum Impagidinium Impagidinium maculatum Impagidinium Diconodinium Diconodinium cristatum Hystrichosphaeridium sp. A Deflandrea sp. i A Micrhystridium si p , bergmann ium Operculodin Senegal inium asymmetricumj inium Senegal Botryococcus sp. Spinidinium densispinatum Paralecaniella Paralecaniella indentata Aptea securigera morulosa Palambages Cymatiosphaera s p . Cyclonephel ium distinctumij ium Cyclonephel cwhitei fium . Cometodin Deflandrea cygniformis D. oebisfeldensis sensu Forma-A Chytroeisphaeridia Chytroeisphaeridia explanj Vozzhenn ikoyia apertura ikoyia Vozzhenn Comasphaeridium cometes Hystr ichosphaer idium' pari idium' ichosphaer um tubil Hystr i d i chosphaer Spinidinium essoi i Hystr Palambages Type I A Iterb i a sp. A a sp. i Iterb A Palaeoperidinium pyrophori Spiniferites ramosus 0 Ligosphaeridium 0 complex Ligosphaeridium A A A V v V A NX A K X X X — A — -x -X -X -X XXX X ------A \x A V V v A V A A X X ------X X X X X X X X — ------X X X ----- X x X X X — A, v x J H W 7 8 (O