PALEOECOLOGY OF THE LOWER DEVONIAN ESOPUS AND CARLISLE CENTER FORMATIONS (TRISTATES GROUP) OF NEW YORK STATE
Michael D. Senglaub
A Thesis
Submitted to the Graduate College of Bowling Green State University in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
December 2004
Committee:
Margaret M. Yacobucci, Advisor
Don C. Steinker
© 2004
Michael D. Senglaub
All Rights Reserved iii
ABSTRACT
Margaret M. Yacobucci, Advisor
The Lower Devonian Esopus and Carlisle Center Formations of New York State are famous for their abundant Zoophycos and lack of other fossils. The goals of this
study were to determine the paleoenvironment during the deposition of the Esopus and
Carlisle Center Formations, to document any fossils present, and describe any
interactions between the trace-makers and other animals.
Numerous fossils are actually present in the Esopus and Carlisle Center
Formations, including sponges, conulariids, articulate and inarticulate brachiopods,
dacryoconarids, ostracodes, conodonts, and fish bones. Associated with some Zoophycos
are Chondrites-like burrows. Chondrites trace-makers may have used Zoophycos traces
as a food source.
Assuming a larger, better-fed, trace-making animal will make larger feeding
structures, Zoophycos size may be used as a paleoenvironmental indicator.
Measurements were made of 312 Zoophycos web radii and 231 meniscus heights from
several localities, and compared to data from the Green Pond Outlier collected by
Marintsch and Finks in 1978. Zoophycos from the Carlisle Center Formation are
consistently larger than those from the Green Pond Outlier, likely because the Green
Pond Outlier represents shallower water than the Carlisle Center Formation.
Small (~10cm wide) unbioturbated lenses are described from the Carlisle Center
Formation. These lenses have Zoophycos around them but not within them, and contain a
concentration of carbonate fossils. The lenses appear to be gutter casts, filled with iv
material transported by storm currents. Calcium phosphate skeletal elements otherwise predominate within the Carlisle Center Formation. It is likely that there is a preservational bias for calcium phosphate and against calcium carbonate, possibly due to the extensive bioturbation in this interval. Since the bioturbators did not enter the gutter casts, the shelly fossils within them were preserved.
From the presence of glauconite, Zoophycos, and gutter casts (but no tempestite deposits), a water depth of 60 to 100m can be inferred for the Carlisle Center Formation.
The Esopus Formation represents somewhat deeper water. The presence of glauconite and Zoophycos also indicate that the Carlisle Center Formation had a low sedimentation rate, and was slightly dysoxic. The Carlisle Center Formation does contain fossils, although many are likely transported or pelagic in origin.
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ACKNOWLEDGMENTS
I would like to thank my advisor, Dr. Yacobucci, for her guidance in the field, laboratory, and as an editor. Without her insight and counsel this project would not be completed. I also thank Dr. Steinker for his guidance and editorial contributions to this thesis. I would also like to thank Dr. Evans for his counsel during the development of this thesis. My appreciation goes out to my family for their constant support and even a small field trip for me. I thank Dr. Carl Brett, of the University of Cincinnati, and Dr.
Charles Ver Straeten, of the New York State Museum, for their help in the initial stages of this study. I am extremely grateful for the support from the Geology Foundation. I am grateful for the help of Bill Butcher in the photo and computer lab. I appreciate the help that Pat Wilhelm, the BGSU Geology Department secretary, gave me on almost a daily basis. I would be lost without her. Finally, I would also like to thank Dr. James Ebert of the State University of New York, College at Oneonta for spurring the interest in studying this interval within me.
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TABLE OF CONTENTS
Page
INTRODUCTION ...... 1
Regional Setting...... 1
Lower Devonian Stratigraphy...... 3
OBJECTIVES……………...... 9
METHODS…………...... 9
Field Work…...... 9
Laboratory Work...... 11
Thin Sections...... 11
Polished Sections...... 12
Conodont Extraction...... 13
Fossil Preparation and Identification ...... 14
STRATIGRAPHY AND GENERAL PALEONTOLOGY...... 14
Esopus Formation ...... 14
Stratigraphy...... 14
Polished Section Descriptions...... 16
Fauna…...... 21
Faunal Descriptions...... 21
Carlisle Center Formation...... 26
Stratigraphy...... 26
Thin Section Descriptions...... 29
Polished Section Descriptions...... 49
Fauna…...... 54 vii
Sponges...... 54
Description...... 54
Interpretation...... 54
Conulariids...... 56
Descriptions ...... 56
Interpretations ...... 59
Brachiopods ...... 61
Descriptions ...... 61
Interpretations ...... 64
Dacryoconarids ...... 66
Description...... 66
Interpretations ...... 66
Ostracodes...... 67
Descriptions ...... 67
Interpretations ...... 69
Holothurians...... 70
Description...... 70
Interpretations ...... 70
Chordates ...... 73
Descriptions ...... 73
Interpretations ...... 73
Trace Fossils...... 76
Descriptions ...... 76
Interpretations ...... 80 viii
THE PALEOENVIRONMENTAL AND PALEOECOLOGICAL SIGNIFICANCE OF
ZOOPHYCOS ………………...... 82
Ichnology Background...... 82
Ichnology Basics...... 82
Ichnofacies Concept...... 84
The Zoophycos Trace Fossil ...... 84
Zoophycos: Two Views...... 86
Size as an Indicator of Environmental Quality...... 88
Supporting Evidence...... 91
Web Radii...... 91
Meniscus Heights...... 104
THE PALEOENVIRONMENTAL SIGNIFICANCE OF GLAUCONITE...... 111
Glauconite: the Mineral ...... 111
Glauconite: Habits ...... 112
Environment of Glauconitization...... 112
Microenvironment ...... 112
Geographic Environment...... 113
Glauconite and Sequence Stratigraphy...... 114
Glauconite in the Carlisle Center Formation ...... 114
DISCUSSION…………………...... 115
Preservational Biases ...... 115
Paleoenvironment…… ...... 117
Unbioturbated Lenses...... 117
On the Origin of Gutter Casts ...... 118 ix
On the Origin of Concretions...... 119
Paleogeographic Trends...... 120
Zoophycos and Their Relation to the Unbioturbated Lenses. 121
Conclusions about the Unbioturbated Lenses...... 122
Apparent Water Depths...... 122
CONCLUSIONS…………… ...... 123
REFERENCES CITED...... 124 x
LIST OF FIGURES
Figure Page
1 Map of Eastern North America...... 2
2 Outcrop Trace of Lower and Middle Devonian Rocks...... 4
3 Stratigraphic Column in the Cherry Valley area ...... 5
4 Map of Green Pond Outlier ...... 6
5 Polished Section from Kingston, Uppermost Esopus Formation ...... 17
6 Polished Section from Kingston, Uppermost Esopus Formation ...... 18
7 Polished Section from Kingston, Uppermost Esopus Formation ...... 19
8 Polished Section from Kingston, Uppermost Esopus Formation ...... 20
9 Small Conulariid from Cottekill Quarry, Esopus Formation...... 22
10 Orbiculoid brachiopod from Shale Pit near Little York ...... 22
11 Orbiculoid brachiopod from Shale Pit near Little York ...... 24
12 Orbiculoid brachiopod from Shale Pit near Little York ...... 24
13 Platyceras spirale from Cherry Valley...... 25
14 Platyceras spirale from Cherry Valley...... 25
15 Large Pyrite Nodule from Shale Pit near Little York...... 26
16 Phosphate Nodule...... 28
17 Smaller Phosphate Nodule...... 28
18 Thin section of MS0103 ...... 30
19 Thin section of MS1003 ...... 30
20 Thin section of MS1103 ...... 32
21 Thin section of MS0703 ...... 34
22 Thin section of MS0703 ...... 35 xi
23 Thin section of MS0703 ...... 36
24 Thin section of MS0803A...... 37
25 Thin section of MS0803A...... 38
26 Thin section of MS0803B...... 39
27 Thin section of MS0803B...... 40
28 Thin section of MS0903 ...... 42
29 Thin section of MS1203 ...... 43
30 Thin section of MS0403 ...... 43
31 Thin section of MS0303 ...... 44
32 Thin section of MS0503 ...... 46
33 Thin section of MS0503 ...... 47
34 Thin section of MS1303 ...... 47
35 Thin section of MS1303 ...... 48
36 Unbioturbated Lens from Cherry Valley, Middle to Upper Carlisle Center
Formation...... 50
37 Chondrites Layer from Cherry Valley...... 51
38 Chondrites Layer from Cherry Valley...... 52
39 Fecal Pellet from Cherry Valley ...... 53
40 Sponge Spicules from Cherry Valley ...... 55
41 Conulariid Cluster from Cherry Valley ...... 57
42 Conulariid Cluster from Cherry Valley ...... 58
43 Conulariid Cluster from Cherry Valley ...... 58
44 Possible Conulariid from Cherry Valley ...... 60
45 Orbiculoid Brachiopod from Cherry Valley...... 60 xii
46 Orbiculoid Brachiopod from Cherry Valley (Detail) ...... 62
47 Orbiculoid Brachiopod from Cherry Valley...... 63
48 Lingulid Brachiopod from Cherry Valley ...... 63
49 Articulate Brachiopod from Cherry Valley ...... 65
50 Dacryoconarid Steinkern from Cherry Valley...... 67
51 Ostracode from Shale Pit near Little York ...... 68
52 Leperditiid Ostracode from Cherry Valley...... 69
53 Holothurian Plate Mold from Cherry Valley...... 71
54 Holothurian Plates from Cherry Valley ...... 72
55 Fish Bone from Cherry Valley ...... 74
56 Fish Bone from Cherry Valley (Detail) ...... 74
57 Icriodid Conodont from Cherry Valley ...... 75
58 Icriodid Conodont from Cherry Valley ...... 76
59 Zoophycos Apex from Cherry Valley...... 77
60 Zoophycos Bedding Plane from Cherry Valley ...... 78
61 Zoophycos Bedding Plane from Cherry Valley ...... 79
62 Scratch Marks from Cherry Valley...... 81
63 Scratch Marks from Cherry Valley...... 81
64 Development of Zoophycos Trace Fossil...... 85
65 Kotake View of Zoophycos...... 87
66 Development of Zoophycos Burrow System ...... 88
67 Chondrites-like Burrows from Shale Pit near Little York...... 89
68 Diagrammatic Sketch of Zoophycos ...... 90
69 Zoophycos Web Radii from Large Block ...... 93 xiii
70 Zoophycos Web Radii from Shale Pit near Little York ...... 93
71 Zoophycos Web Radii from Upper Block...... 94
72 Zoophycos Web Radii from Lower Block ...... 94
73 Zoophycos Web Radii from Kingston...... 95
74 Zoophycos Web Radii from Mountainville Unit A Member...... 96
75 Zoophycos Web Radii from Mountainville Unit B Member ...... 96
76 Zoophycos Web Radii from Mountainville Unit C Member ...... 97
77 Zoophycos Web Radii from Mountainville Unit D Member...... 97
78 Zoophycos Web radii from Quarry Hill Member ...... 98
79 Zoophycos Web Radii from Highland Mills Member ...... 98
80 Zoophycos Web Radii from Eddyville Member ...... 99
81 Zoophycos Web radii from Woodbury Creek Member ...... 99
82 Zoophycos Meniscus Heights from Kingston...... 106
83 Zoophycos Meniscus Heights from CVCC 1-6 ...... 106
84 Zoophycos Meniscus Heights from Cobleskill (Below Prominent Bed)...... 107
85 Zoophycos Meniscus Heights from Cobleskill (Within Prominent Bed) ...... 107
86 Zoophycos Meniscus Heights from Shale Pit near Little York ...... 108
87 Zoophycos Meniscus Heights from Large Block...... 108
88 Glauconitization of a Granular Substrate...... 112
xiv
LIST OF TABLES
Table Page
1 Stratigraphic Relations Between the Main Outcrop Belt and Green
Pond Outlier...... 7
2 Locality Information ...... 10
3 Statistical Information from Web Radii Samples ...... 100
4 T-Test Comparison of Zoophycos Web Radii from Main Outcrop Belt...... 102
5 T-Test Comparison of Zoophycos Web Radii from Green Pond Outlier...... 102
6 T-Test Comparison of Zoophycos Web Radii from Main Outcrop Belt and
Green Pond Outlier ...... 103
7 Statistical Information on Meniscus Height Samples...... 109
8 T-Test Comparison of Zoophycos Meniscus Heights ...... 110
1
INTRODUCTION
The Devonian of New York is one the most well studied packages of Devonian- age rocks in the world. The Helderberg (Lower Devonian) and Hamilton (Middle
Devonian) Groups are world famous for their fossil assemblages, yet the intervening
Tristates (Lower Devonian) Group has been relatively understudied.
The objectives of this thesis are to describe the paleontology, ichnology, and sedimentology of the Esopus and Carlisle Center Formations of New York State.
Workers in New York geology have tended to bypass these formations in favor of studying the more fossiliferous Helderberg Group and Onondaga Formation. This may be due in large part to the ubiquitous presence of the Zoophycos trace fossil in the Esopus and Carlisle Center Formations, which obscures most if not all other sedimentary structures, and the apparent lack of any shelly fauna.
Regional Setting
New York falls within the Appalachian foreland basin (Figure 1), which has existed since at least Cambrian times. The Appalachian basin extends from New York southwest down toward Alabama. The basin formed from numerous tectonic loading events that accreted material onto the edge of the craton (i.e., orogenies) during the
Paleozoic. This loading created proximal uplift in the areas adjacent to the loading, where as in the distal areas affected by the loading downwarping occurred, creating the
foreland basin. Sediments from the newly created mountains (e.g., Queenstown and
Catskill Deltas) then filled in these newly created basins. As sediments filled the basin,
new tectonic activity would occur and further downwarp the basin, creating new
accommodation space for additional sedimentation (Faill, 1985). 2
Figure 1: Map of eastern North America, showing the various terranes, including Avalon, the Appalachian Foreland Basin, and the Laurentian craton. From Faill, 1985, p. 16.
During the early to mid-Paleozoic, New York was a very geologically active area.
During the Late Ordovician, the Taconic Orogeny occurred when an island arc was accreted to the North American plate. This orogeny was not large enough to create large- scale deformation of the craton. The Taconic terrane now resides along the Hudson
River Valley. The mountains that are now called the Taconic Mountains east of the
Hudson River are the uplifted and thrust faulted metamorphic remnant of the much larger
original Taconic Mountains. These mountains were then eroded down during the
Silurian. In the Early Devonian, the New York area of the Appalachian Basin was
relatively quiet and stable. The abundant carbonates and mature quartz sands of the
Lower Devonian in New York reflect this relative quiescence.
The calm ended in the Middle Devonian when the Avalonian micro-continent
accreted to the North American plate during the Acadian Orogeny (Figure 1). This
orogeny created the Acadian Mountains, which began to erode as soon as they were
formed. Sediments created by this erosion produced the Catskill Clastic Wedge, a thick 3 sequence of terrigenous rocks, which is famous for its Gilboa Forest, a Givetian-aged lycopsid forest found near Gilboa, New York (Banks et al., 1985).
During the Permian, the Alleghanian Orogeny occurred, during which North
Africa collided with North America and Baltica, producing the Appalachian Mountains.
Any of the Permian sediments deposited in New York have been eroded away. This orogeny created a large fold and thrust belt found along the entire Atlantic Seaboard.
This belt extends into New Jersey and New York; much of the Hudson Valley’s rocks were folded during this orogeny.
Prior to each orogeny, there was an associated downwarping of the continental crust, deepening the basins. These basins then filled in with a generally shallowing upward sequence of facies, eventually filling in completely. As tectonic downwarping subsided, there was a distinct facies change from siliciclastic to a more carbonate- dominant deposition. These carbonates often are very fossiliferous and produce some of the most well preserved fossils in the world.
During much of the Devonian, a great diversity of life thrived in the marine environment, but the Esopus and Carlisle Center Formations of New York and New
Jersey show depauperate, low-diversity fossil assemblages, especially for typical
Devonian invertebrate taxa. This disproportionately low diversity may be because of unfavorable living conditions or could possibly be a preservational artifact. However, the
environment must not have been entirely inhospitable, as Zoophycos trace fossils are
abundant throughout this interval.
Lower Devonian Stratigraphy 4
The Lower Devonian units outcrop along the Mohawk and Hudson River valleys of New York State (Figure 2). The main outcrop belt is from Columbia Center in Central
New York east to Clarksville and south to Port Jervis and southwest into Pennsylvania.
Another area of outcrop east of the main outcrop belt is located in the Greenwood Lake
area of New York and New Jersey. The Green Pond Outlier is composed of a sequence
of Silurian and Devonian strata, in a general synclinal form. The outlier stretches from
near Cornwall, New York southwest to near Dover, New Jersey (Boucot et al., 1970;
Marintsch and Finks, 1978, 1982).
Figure 2: Outcrop trace of Lower and Middle Devonian rocks. Redrawn from Linsley, 1994.
The Lower Devonian in New York consists of two large stratigraphic groups, the
Helderberg and the Tristates Groups (Figure 3). The Helderberg is broken into the
Manlius, Coeymans, Kalkberg, New Scotland, Becraft, Alsen, and Port Ewen
Formations, all of which are very fossiliferous. At the top of the Helderberg, there is a major regional unconformity, the Wallbridge Unconformity. The erosional down cutting that formed this unconformity, vary greatly over the state. Around the Port Jervis area 5
(Figure 2) there are very few strata missing, but to the north and west the amount of strata missing increases until, in the western parts of the state, the Middle Devonian lies directly on Silurian rocks. The Tristates Group is composed of the Port Jervis, Glenerie,
Oriskany, Esopus, Carlisle Center, Bois Blanc, and Schoharie Formations. The Port
Jervis Limestone only outcrops in the vicinity of Port Jervis and is the oldest formation in the Tristates Group. The Glenerie Limestone is a more calcareous equivalent to the
Figure 3: Stratigraphic column in the Cherry Valley area. From Fisher, 1979 p. 24.
6
Oriskany Sandstone, into which it grades to the west. The Esopus, Carlisle Center, and
Schoharie Formations represent the majority of the Tristates Group. The Esopus is a thick sequence of shale and is characterized by the presence of Zoophycos and the lack of
other fauna throughout most of the outcrop belt. The Carlisle Center Formation is a
calcareous siltstone characterized by the ubiquitous presence of Zoophycos and an
apparent lack of any other fossils. The Schoharie Formation is a moderately fossiliferous
calcareous silty to sandy mudstone (Boucot et al., 1970; Ver Straeten and Brett, 1995).
The Green Pond Outlier (Figures 2 and 4) has a unique stratigraphy as compared
to the rest of the outcrop belt. The Helderberg Group is present but the Stone Ridge
Group has replaced the Tristates Group. The Stone Ridge Group is composed of the
Connelly Conglomerate (Oriskany equivalent), Esopus, and Pine Hill Formations
(Schoharie/Onondaga equivalent) (Boucot et al., 1970; Ver Straeten and Brett, 1995).
Figure 4: Map of Green Pond Outlier. Redrawn from Boucot, 1970. 7
The Esopus Formation in the main outcrop belt is subdivided into three members, the lower, middle, and upper members. The Esopus Formation in the Green Pond Outlier is subdivided into four members, the Mountainville, Quarry Hill, Highland Mills, and the
Eddyville Members (Table 1) (Boucot et al., 1970; Ver Straeten and Brett, 1995).
Stone Onondaga Ridge Pine Hill Formation Group Formation Kanouse Member Tristates Schoharie Woodbury Creek Group Formation Member Carlisle Center Esopus Formation Formation Eddyville Member Esopus Formation Highland Mills Member Oriskany Formation Quarry Hill Member Mountainville Member Connelly Conglomerate Table 1: Stratigraphic relations between the main outcrop belt (left) and Green Pond Outlier (right). Tie lines at center represent lateral equivalents.
The Schoharie Formation in the main outcrop belt is subdivided into three
members, an unnamed member and the Aquetuck and Saugerties Members (Ver Straeten
and Brett, 1995). The unnamed member is an equivalent to the Carlisle Center Formation
of Goldring and Flower (1942). In this thesis, I will refer to these rocks as the Carlisle
Center Formation. In the Green Pond Outlier, the Schoharie equivalent is the Pine Hill
Formation and is subdivided into two members, the Woodbury Creek and Kanouse
Members (Boucot et al., 1970; Ver Straeten and Brett, 1995).
In the main outcrop belt, the Carlisle Center and Schoharie Formations gradually
pinch out to the west, and the Bois Blanc (Schoharie equivalent) appears in western New
York and continues into Ontario, Canada. One reason for this shift was a paleo- 8 topographic high occupying central to west-central New York and northwest
Pennsylvania. This bulge starts around the Syracuse area and trends southwest into
Pennsylvania. Ver Straeten and Brett (2000) have traced reef crests within the Onondaga
Formation throughout this region. They surmise that this bulge or high was a result of the first technophase of the Acadian Orogeny. In this area, erosion or nondeposition was
the main process; in much of the bulge area, all of the Tristates and the Helderberg
Groups are missing.
The Carlisle Center Formation is especially well exposed at a road cut along U.S.
Route 20 near the town of Cherry Valley, New York. At this locality, an abrupt
lithologic change, from grey shale to quartz siltstone, is evident between the Esopus and
Carlisle Center Formations. The nature of this contact has been the topic of much debate.
This contact has been described as an unconformity, or a short depositional hiatus, while
others have claimed the contact was still unconsolidated when deposition of the Carlisle
Center Formation began (Johnson, 1957; Johnson and Southard, 1962; Miller and
Rehmer, 1982; Liebe and Grasso, 1990; Ver Straeten and Brett, 1995).
In the main outcrop belt, the Esopus and Carlisle Center Formations are notable
for their lack of abundant shelly fauna. However, the Zoophycos trace is present
throughout this interval. Zoophycos is a very distinctive spiral feeding trace fossil of a
soft-bodied worm. Previous studies conducted on the trace fossil in other study areas,
notably Japan and New Zealand, have focused on its morphology and its use as a
paleobathymetric indicator (present below storm wave base and above turbidite
sedimentation) (Seilacher, 1967; Ekdale, 1992; Kotake, 1989, 1990, 1991, 1992, 1993,
1994, 1997). At the Green Pond Outlier, Marintsch and Finks (1978, 1982) measured 9
Zoophycos size in the Esopus and Pine Hill Formations to estimate the quality of the paleoenvironment for the animal. Their study was based on the idea that the Zoophycos
trace maker would grow larger in more suitable environments.
OBJECTIVES
In this thesis, I will demonstrate with supporting evidence the paleoenvironment
for both the Esopus and Carlisle Center Formations. This evidence will include the
sedimentology of the formations and their fossil content, including size and number
present. The origin and significance of the unbioturbated lenses will also be addressed.
(In this thesis, I will refer to lenses that occur in the Carlisle Center Formation as
unbioturbated lenses, but these lenses are only not bioturbated by Zoophycos. Other
small burrows may exist within the lenses.)
I will document the fossils present, and discuss any preservational biases
associated with the fossil assemblages. Finally, I will discuss any interactions between
the trace fossil makers and the other animals that may have coexisted with them.
METHODS
Field Work
Outcrops of the Tristates Group were located from previous field trips and from
additional sources such as field trip guidebooks and papers. Geological maps were used
to locate additional outcrops in the field area. Land owners were contacted if access was
needed to their lands. Most of the sites studied were road and railroad cuts. Safety
equipment, including high visibility vests, was used to ensure the safety of the geologists
and passing motorists. 10
The field work was conducted in July 2003. Several outcrops were studied in the
Mohawk and Hudson River valleys. Localities are listed in Table 2. Most of these sections have been highly bioturbated by the Zoophycos trace makers and therefore the determination of individual beds was impossible. Measured sections were not taken at any of these locations because of the degree of bioturbation. Observations on stratigraphy and sedimentology were recorded in field notebooks. Rough estimates of thickness were made using a Brunton compass as an eyelevel. Global Positioning System coordinates were taken at some localities, using the NAD CONUS datum. Measurements were taken in the UTM coordinate system.
Formations Green Pond Outlier Localities Present UTM Coordinates Railroad cut east of Highland Mills, NY ES, PH Western shore of the south end of Greenwood Lake, NJ ES, PH
Main Outcrop Localities Former aggregate pit, one mile east of Cottekill, NY ES, CC 12 km southwest of Kingston NY North and south sides of Route 199 in Kingston, NY ES, SC North and south sides of Route 23 south of Leeds, NY ES 40 km north of Kingston Aggregate pit south of the town of Little York, NY ES, CC, ON 18T 0541014 4733111 25 km east of Cherry Valley, NY Empty lot on the south side of Route 7 in Cobleskill CC,ON 18T 0545698 4725185 Along US Route 20 east and west of its intersection ES, CC, ON E 18T 0522358 4740940 with Route 166 northeast of Cherry Valley, NY W 18T 0521129 4740975
Table 2: Locality information. See also maps provided in Figures 2 and 4. Key: ES = Esopus Formation, CC = Carlisle Center Formation, SC = Schoharie Formation, PH = Pine Hill Formation, ON = Onondaga Formation.
Outcrops were scoured for any fossils present. Macrofossils found were bagged
and tagged using heavy-duty Ziplock bags. Any pertinent information, including date, 11 stratigraphic position, and locality, was written on the bag with a permanent marker.
When oriented samples were taken, orientations were noted on the sample. The samples in their bags were then placed in boxes or shallow plastic tubs to be transported to the laboratory in Bowling Green, Ohio.
Small rock samples were taken for later lithologic and thin section analysis.
These samples were placed in heavy-duty Ziplock bags and labeled with pertinent information, including date, stratigraphic position, and locality. Large slabs were also taken for later cutting, using diamond rock saws, to reveal trace fossil morphology.
Zoophycos web radii were measured in the field using a standard metric tape measure. On bedding surfaces, one end of the tape measure was placed at the center of the web and measurements of the web were taken outwards toward the perimeter of the web. These measurements were then recorded in a field notebook and later used in statistical analyses. Zoophycos menisci were measured using a small metric ruler. A
Zoophycos meniscus was located on the outcrop and, with the ruler roughly parallel to the rock face, the height of the meniscus was measured. The maximum distance between the two tails of the chevrons was taken to establish consistency in measurements.
Laboratory Work
Thin Sections
A total of 11 thin sections were made to further analyze the lithology and cementation of the units studied. One thin section was made from rocks near the contact between the Esopus and Carlisle Center Formation. Two thin sections were made from rocks near the contact between the Carlisle Center and Onondaga Formations. Two thin sections were made from samples within the middle of the Carlisle Center Formation. 12
Six thin sections were made from lenses of unbioturbated sediment from the Carlisle
Center Formation to determine if there was a lithologic reason that the Zoophycos trace maker did not enter these areas. For instance, these could contain coarser grains or possibly more angular grains, something that a small soft-bodied animal would not ingest. Special consideration was made to what happens to the sediment when the
Zoophycos animal traveled through, and how this affected the rock’s cohesiveness.
Thin sections were made using a Logitech thin section grinding machine (model
number LP30). A chip was made no larger than a regular petrographic slide. The chip
was impregnated with blue epoxy using a vacuum. The impregnated chip was then
ground to remove the excess epoxy and was then epoxyed to a preground petrographic
slide. The slide and chip were then placed in a jig, which applies pressure to remove any
air bubbles. When the epoxy was set, the excess rock was removed with a Hillquest saw
and grinder. The slide was placed on the Logitech machine and was ground to
approximately 30 microns thick. Some additional hand grinding using a glass plate and
600 grit was necessary for some slides.
Polished Sections
Slabs of rock were cut to measure no more than 15 centimeters by 15 centimeters.
Special efforts were taken to polish samples from the Kingston Esopus Formation
outcrops because of their generally dark color. This dark color hinders the viewing of
any sedimentary structures; a good polish will bring out previously invisible structure
within the rock. These rocks were polished on lapidary wheels. A sequence of grits was
used to polish the rock slabs, starting with a 320 grit, then a 400 grit, and finally a 600 13 grit. Some smaller sections were polished further with a 1000 grit for better visibility of the sedimentary structures and/or fossils.
Conodont Extraction
Conodonts are very good biostratigraphic markers and are very useful for correlation to other areas. This is why conodont extraction was attempted from these units. Special consideration was taken to determine any differences in conodont content between the unbioturbated lenses and the Zoophycos burrowed areas.
To remove conodonts from the matrix, normal methods of extraction do not apply. Typically, conodont studies utilize carbonate rocks and use relatively weak acids
(e.g., acetic or hydrochloric acids) to disassociate the rocks. These acids do not harm the
conodonts and conodonts can be separated from the disassociated matrix by density
differences using heavy liquids. The rocks being studied here require more vigorous
methods to remove any microfossils, because they are cemented with both calcite and
silica. The former easily dissolves in weak acids, but the latter is highly resistant to weak
acids even at high concentrations.
Eighteen samples were selected from the Carlisle Center Formation; nearly all
were from the Cherry Valley outcrops. Most of the samples were from the unbioturbated
lenses; these areas were the most indurated areas and required the strongest acids to
disassociate the sediments.
Hydrofluoric acid (HF) was used to disassociate the sediments. A concentration
of approximately 10 percent HF was used to disaggregate small samples (~25 grams).
Breaking the rock sample into smaller pieces produced more disaggregated sediment than
cutting the samples into small cubes. The samples and HF were placed in polypropylene 14 beakers for up to 72 hours. The solution was decanted off twice and was neutralized with sodium carbonate. The remaining sediment was then sieved through 125 and 1190 micron sieves. Each sample yielded zero to four conodonts. The low yield is due to the small sample size and possibly some dissolution of the conodonts in the HF. HF does dissolve calcium phosphate, of which conodonts are made. However, several of the conodonts survived the acid bath, so dissolution was not complete.
Fossil Preparation and Identification
The fossils collected required minimal preparation. Specimens from the field were washed in water to remove any loose sediment and reveal any small features.
Removal of fossils from the surrounding matrix was not accomplished because of the hardness of the rocks. Fossils were identified using the Treatise on Invertebrate
Paleontology. Most fossils could be identified to some level, but due to the poor preservation or inability to see all features, some were not identified.
STRATIGRAPHY AND GENERAL PALEONTOLOGY
Esopus Formation
Stratigraphy
The Esopus Formation is a blue to gray to black, noncalcareous argillaceous shale, with the color depending on how weathered the rock face is. The Zoophycos trace fossil is present throughout the unit. This trace fossil creates instability in the rock, and when weathered the rocks will crumble. It is difficult to see bedding on weathered surfaces because of this. It is better to trench down to see any bedding or Zoophycos.
The Esopus Formation is divided into three members: a lower, middle, and upper
(Ver Straeten and Brett, 1995). As the Esopus Formation is a homogeneous formation, 15 the three members are very similar. The greatest thickness, over 150 meters, of the
Esopus Formation is in the main outcrop belt near Port Jervis, New York (Miller and
Rehmer, 1982). North and especially west the thickness decreases, such that the middle and lower member are only present at Cherry Valley, New York. West of Cherry Valley, the Esopus Formation eventually pinches out so that Middle Devonian rocks are lying directly on Silurian rocks. This westward thinning creates a dilemma with the nature of the overlying Carlisle Center Formation contact with the Esopus Formation at Cherry
Valley. On the contact itself, there are several scratch marks probably produced by an arthropod stuck in the mud, but these scratches were made into the underlying Esopus
Formation, specifically the middle member. The Carlisle Center Formation was then deposited, filling in the scratch marks and preserving them. This would imply that the top of the Esopus was not lithified when the Carlisle Center Formation began deposition
(and thus was able to be scratched and quickly filled), and that the upper member was never deposited at Cherry Valley.
Miller and Rehmer (1982), studying this contact in some detail, identified
Cruziana and Fustiglyphus as being present at this contact. They have concluded that there was a thin veneer of Carlisle Center Formation sediments on top of the Esopus
Formation sediments. The trace makers then burrowed down through the Carlisle Center sediments and scratched the now firm, but not lithified, Esopus sediments. If these sediments were “soupy,” in that they had a high water content, there would be deformation structures evident in the casts within the Carlisle Center Formation, but this was not observed (Miller and Rehmer, 1982).
16
Polished Section Descriptions
Kingston, uppermost Esopus Formation. Dark shale with Chondrites and Zoophycos
traces present. Figure 5 shows the Chondrites traces (lower third of specimen) being
replaced with some mixing (at center) by Zoophycos traces (middle to upper). This
region has experienced tectonic deformation, which likely produced the small scale
fractures filled with calcite at upper center. Figure 6 shows the other side of the same
slab shown in Figure 5. One can see similar mixing of ichnofossils but a larger mixing
zone between the two ichnofacies.
Kingston, uppermost Esopus Formation. Dark shale with Chondrites and Zoophycos
traces present. Figure 7 shows abundant Zoophycos with minor Chondrites traces. At the
upper right, there is a slight abrupt change in lithology from dark shale to lighter silt.
Areas like this are common in the uppermost Esopus Formation near the contact with the
Schoharie Formation. Pyrite nodules are also present. Figure 8 is the other side of the same slab shown in Figure 7. Figure 8 shows a distinctive Zoophycos at left center; this trace has been cut at an angle, which produces progressively larger chevrons. 17
A
Centimeter scale
B
Figure 5: Polished Section from Kingston, uppermost Esopus Formation. A: Normal view; B: Negative and contrast enhanced. Note distinctive change in ichnofossils present from bottom to top. Scale applies to both A and B. 18
A
Centimeter scale
B
Figure 6: Polished Section from Kingston, uppermost Esopus Formation. A: Normal view; B: Negative and contrast enhanced. Note distinctive change in ichnofossils present from bottom to top, with a somewhat thicker mixing zone in between as compared to the previous figure. Scale applies to both A and B. 19
A Centimeter scale
B
Figure 7: Polished Section from Kingston, uppermost Esopus Formation. A: Normal view; B: Contrast enhanced. Note contact at top right and pyrite nodule at lower center. Scale applies to both A and B. 20
A
Centimeter scale
B
Figure 8: Polished Section from Kingston, uppermost Esopus Formation. A: Normal view; B: Contrast enhanced. Note distinctive Zoophycos, at left, cut at an angle to produce progressively larger chevrons. White streaks at lower center are scratches from polishing. Scale applies to both A and B. 21
Fauna
The paleontology of the Esopus Formation has not received much attention. This is especially true in the main outcrop belt. Other workers have found small brachiopods,
Atlanticocoelia acutiplicata, in the Esopus Formation (Boucot and Rehmer, 1977; Koch,
1996). In a quarry near Cottekill, New York, several lamellorthoceratid nautiloid cephalopod species were found, with their unique cameral deposits (Stanley and Teichert,
1976). The by far most abundant fossil of the Esopus Formation is the Zoophycos trace fossil. Zoophycos is found in both the main outcrop belt and in the Green Pond Outlier.
I have found very few fossils in the Esopus Formation. They include several
Atlanticocoelia acutiplicata brachiopods and a small conulariid from the Cottekill
Quarry. At Cherry Valley, I have only found a slightly crushed platyceras gastropod. At a shale pit near Little York, I have found two orbiculoid brachiopods partially replaced by pyrite. I have also found numerous pyrite nodules, some up to 10 centimeters long.
Pyrite nodules represent a small amount of organic material on which pyrite has been deposited in local anoxic conditions. If each of these nodules represents one organism, the population of the Esopus Formation may be much larger.
Faunal Descriptions
Conulariid: Cottekill Quarry, Esopus Formation, float.
Small conulariid preserved with original skeletal material in shale. Rods are preserved but difficult to count for identification within Conularia. Measures 1.2 centimeters long.
Figure 9 shows the lower portion of the conulariid. See Carlisle Center Formation section below for discussion of conulariids. 22
Figure 9: Small conulariid from Cottekill Quarry, Esopus Formation.
Figure 10: Orbiculoid brachiopod from Shale Pit near Little York, upper 3.5 meters of Esopus Formation. Inarticulate brachiopod partially replaced by pyrite.
23
Orbiculoid brachiopod: Shale Pit near Little York, upper 3.5 meters of Esopus, float.
Two inarticulate brachiopods that have been partially replaced by pyrite (Figure 10).
These brachiopods both have the typical features of an orbiculoid brachiopod, including a
convex brachial valve with a circular valve shape and prominent growth lines (Figures 11 and 12). Both have only the brachial valve preserved. Both measure approximately 6 mm across.
Platyceras spirale: Cherry Valley, upper 2 m of Esopus Formation, float.
Small gastropod partially crushed in shale (Figures 13 and 14). Original shell material with growth lines preserved. In Figure 13 the body chamber is clearly crushed, with noticeably lighter colored sediment, lighter than the shell color, filling the body chamber.
The sediment infilling the shell is the surrounding shale. Measures 3.8 centimeters from
apex to opening.
Pyrite nodule: Little York Shale Pit, Esopus Formation, float.
Large pyrite nodule (Figure 15). Measures approximately 9.5 centimeters long. Interior
is nearly all pyrite with some sparry calcite. This nodule was found in float likely from
the Esopus Formation. 24
Figure 11: Orbiculoid brachiopod from Shale Pit near Little York, upper 3.5 meters of Esopus. Orbiculoid brachiopod partially replaced by pyrite.
Figure 12: Orbiculoid brachiopod from Shale Pit near Little York, upper 3.5 meters of Esopus. Orbiculoid brachiopod partially replaced by pyrite. 25
Figure 13: Platyceras spirale from Cherry Valley, upper 2 m of Esopus Formation. Note light colored sediment in body chamber. Centimeter scale.
Figure 14: Platyceras spirale from Cherry Valley, upper 2 m of Esopus Formation. Note crushed body chamber. Centimeter scale. 26
Figure 15: Large pyrite nodule from Shale Pit near Little York, Esopus Formation. Note light-colored sparry calcite at center. Centimeter scale.
Carlisle Center Formation
Stratigraphy
The Carlisle Center Formation is a quartz siltstone with variable amounts of glauconite. At the contact with the Esopus Formation at Cherry Valley, New York, the formation is nearly a green sand, with more glauconite than quartz silt and sand. This contact is somewhat undulate with probable scratch marks on the sole of the bed preserved from the high spots from the Esopus Formation (see Esopus Formation stratigraphy above). Only a centimeter above the contact there is the first occurrence of
Zoophycos. As one travels up section, the glauconite content declines in amount but does not disappear. The middle of the formation is characterized by the presence of 27
Zoophycos and the appearance of unbioturbated lenses. A discussion of the origin of
these lenses can be found in the discussion section. The upper sections of the formation
are characterized by more Zoophycos and an increase in glauconite. This increase in
glauconite peaks at the gradational contact with the overlying Onondaga Formation
(Edgecliff Member), where lithology changes from a quartz siltstone to a muddy
limestone. In this 20-30-centimeter-thick portion of the section, Zoophycos is absent,
with the only trace fossil present being Chondrites. Slightly higher in the section, there
are numerous large (10 centimeters) phosphate nodules, which have been bored (Figures
16 and 17). Some of these nodules have nucleated on fossils, including a lingulid
brachiopod.
At a shale pit near Little York, New York, the Esopus and Carlisle Center
Formations are freshly exposed. At the contact between the two formations there is a
lithology change from shale to siltstone, but the contact between them is gradual and
difficult to determine. The glauconized layer with phosphate pebbles near the contact is
absent at this locality. The absence of the glauconitic layer is interpreted as a deepening
of the basin as one travels east in the basin toward the Hudson Valley.
In this shale pit, only the lowermost portions of the Carlisle Center Formation are
present. This section is marked by the presence of Zoophycos and a possible small
unbioturbated lens. The paleogeographic implications of this smaller unbioturbated lens
are discussed in the discussion section. Glauconite is present in these rocks but much less
abundant that at the Cherry Valley outcrops. 28
Figure 16: Phosphate nodule, contact between Carlisle Center and Onondaga Formations. Note borings. Scale in centimeters.
Figure 17: Smaller phosphate nodule, contact between Carlisle Center and Onondaga Formations. Note borings. Scale in centimeters.
29
The Zoophycos in the Carlisle Center Formation occur in discrete packages. One
Zoophycos trace is stacked on top of another. When the Zoophycos trace-making animal
(probably a worm) travels through the sediment, the animal pushes and compacts the
sediment on the outside of the burrow. As the animal does this, the grains become
oriented along the outside of the burrow. This in turn will produce instability in the rock
and will eventually create cracks in the rock along these planes of weakness. This
increase in porosity can create conduits to transport ground water and remove or deposit
carbonate material or other minerals. Combined with jointing, this instability can also
create a rockfall problem, as seen in Cherry Valley, where several large blocks have
fallen and exposed wonderful bedding planes covered in Zoophycos.
Thin Section Descriptions
In this section, the thin section descriptions are arranged in stratigraphic order.
This was done to better show stratigraphic change over time.
Description of MS0103: Cherry Valley, Contact between Esopus and Carlisle Center
Formations.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to subrounded, quartz sand, with ferruginous cement. Abundant glauconite. Zoophycos present, concentrating clay particles in the burrow. Figure 18 shows a glauconite grain showing two shades of green. This grain may be relict, with a growth ring of secondary glauconite around the previously formed glauconite, or as this grain formed, the potassium content of the pore fluids decreased, creating the ring around the grain.
Glauconite grains with rings and partial rings are a common feature at the lower and 30
Figure 18: Thin section of MS0103 XP, Cherry Valley, Contact between Esopus and Carlisle Center Formation. Note glauconite grain with ring left of center.
Figure 19: Thin section of MS1003 XP Shale Pit near Little York, Contact between unbioturbated lens (right) and Zoophycos (left), 2 meters above Esopus and Carlisle Center Formation contact. 31 upper contacts within this unit. Grains composed entirely of the lighter shade of green are also abundant.
Description of MS1003: Little York Shale Pit, Contact between unbioturbated lens and
Zoophycos, two meters above Esopus and Carlisle Center Formation contact.
Subangular to subrounded quartz silt with ferruginous and calcite cement. Glauconite
present. No shelly material present. Within the unbioturbated lens there is less clay
cement. In the outside of the unbioturbated lens there is more clay, which may be due to
the abundance of Zoophycos mixing the sediments. Figure 19 shows the contact between
the two areas. The lighter area on the right is the unbioturbated lens and on the left is the
Zoophycos area, which is darker because of the higher clay content.
Description of MS1103: Cherry Valley, two meters above Esopus and Carlisle Center
Formations contact.
Subangular quartz silt with ferruginous and calcite cement. Glauconite rare. Figure 20
depicts the opaque ferruginous cement along with the paler higher order calcite cement.
Description of MS0703: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to
subrounded, quartz sand with ferruginous and calcite cement. Glauconite and plagioclase
with albite twinning present. Numerous small semi-circular valves, possibly ostracodes, 32
Figure 20 A: Thin section of MS1103 XP, Cherry Valley, two meters above Esopus and Carlisle Center Formation contact. Note dark ferruginous cement.
Figure 20 B: Thin section of MS1103, plane-polarized view of slide in part A. 33 are present. Shelly material concentrated in the dark clay material. Figure 21 depicts a possible small high-spired snail or dacryoconarid. Figure 22 shows glauconite surrounding some shell material, possibly nucleating on it. Figure 23 depicts a possible single sponge spicule.
Description of MS0803A: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to subrounded, quartz sand with ferruginous and calcite cement. Glauconite present. Fossils are concentrated in burrow segments. Figure 24 shows a possible sponge spicule; the opaque material in the center of the spicule is pyrite, which may have infilled the axial canal where the organic spongin fiber would originally have been. Figure 25 depicts a possible curved tentaculitid or ostracode with reticulations.
Description of MS0803B: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to subrounded quartz sand with ferruginous and calcite cement. Glauconite present. Clay concentrations are low within the burrow fill. Figure 26 shows a circular object probably a dacryoconarid that has been sectioned perpendicular to the shell. The shell is filled with a calcite fill. Figure 27 depicts two probable sponge spicules, based on the pyrite fill within the central area of the spicule. These two circular structures are composed almost entirely of one single crystal, as a sponge spicule might be. 34
Figure 21 A: Thin section of MS0703 XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note small high-spired gastropod in center.
Figure 21 B: Thin section of MS0703, plane-polarized view of slide above. 35
Figure 22 A: Thin section of MS0703 XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note glauconite grains surrounding shell fragment.
Figure 22 B: MS0703, plane-polarized view of figure above. 36
Figure 23 A: MS0703 XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note sponge spicule in center.
Figure 23 B: Thin section of MS0703, plane-polarized view of figure above. 37
Figure 24 A: MS0803A XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note sponge spicule in center with opaque pyrite infilling axial canal.
Figure 24 B: Thin section of MS0803A, Plane-polarized view of figure above. 38
Figure 25 A: MS0803A XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note shell material at center.
Figure 25 B: Thin section of MS0803A, Plane-polarized view of above figure. 39
Figure 26 A: Thin section of MS0803B XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note dacryoconarid at center.
Figure 26 B: Thin section of MS0803B, Plane-polarized view of figure above. 40
Figure 27 A: Thin section of MS0803B XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note sponge spicule lower center and upper center.
Figure 27 B: Thin section of MS0803B, Plane-polarized view of figure above. 41
Description of MS0903: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation.
Subangular quartz silt with ferruginous and calcite cement. Glauconite and plagioclase,
similar to MS0703 above, present. Figure 28 shows a portion of an ostracode.
Description of MS1203: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation.
Subangular quartz silt with ferruginous and calcite cement. Figure 29 shows the hinge
area of an articulate brachiopod. The shell material has been recrystalized and no longer
resembles the typical brachiopod shell section.
Description of MS0403: Cobleskill, prominent bed near top of Carlisle Center Formation.
Subangular quartz silt with ferruginous cement. Glauconite nearly absent. Well-
pronounced Zoophycos (Figure 30).
Description of MS0303: Cherry Valley, contact between Carlisle Center and Onondaga
Formations.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to subrounded quartz sand with ferruginous cement. Glauconite concentrated in Chondrites burrows. This sample has been thoroughly bioturbated by the Chondrites trace maker.
Abundant small ostracodes not concentrated within the burrows. Figure 31 shows similar 42
Figure 28 A: Thin section of MS0903 XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note ostracode at center.
Figure 28 B: Thin section of MS0903, Plane-polarized view of figure above. 43
Figure 29: Thin section of MS1203 XP, Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note articulate brachiopod hinge area.
Figure 30: Thin section of MS0403 XP, Cobleskill, prominent bed near top of Carlisle Center Formation. Note Zoophycos at right. 44
Figure 31 A: Thin section of MS0303 XP, Cherry Valley, Contact between Carlisle Center and Onondaga Formations. Note glauconite grain with ring.
Figure 31 B: Thin section of MS0303, Plane-polarized view of above figure. 45 glauconite overgrowths to those described in MS0103 (contact between Esopus and
Carlisle Center Formations).
Description of MS0503: Cherry Valley, contact between Carlisle Center and Onondaga
Formations.
Abundant subangular to subrounded quartz silt, and rare very fine grained, subangular to subrounded quartz sand with ferruginous cement. Plagioclase present. Glauconite concentrated in Chondrites burrows. Abundant small ostracodes. Figure 32 shows similar glauconite overgrowths to those described in MS0103 and MS0303 (see above). Figure
33 shows a Chondrites burrow with glauconite concentrated within it. Note also that the
other particles have been oriented in a circular fashion within the burrow.
Description of MS1303: Cherry Valley, contact between Carlisle Center and Onondaga
Formation.
Subangular to subrounded quartz silt with ferruginous and calcite cement. Abundant
glauconite concentrated in Chondrites burrows. Abundant small fossils of ostracodes and
dacryoconarids. Many have been oriented by the movement of the Zoophycos and
Chondrites trace-making animal through the sediment. Figure 34 shows a Zoophycos
trace moving from bottom left to top right. This trace shows how the alignment of
sedimentary particles has created a structural weakness within the rock resulting in a
crack (upper left of Figure 34). Figure 35 depicts the apex of a dacryoconarid. The
interior cavity is filled with opaque ferruginous material. This specimen is too thick to be
a sponge spicule and is composed of calcite. 46
Figure 32 A: Thin section of MS0503 XP, Cherry Valley, contact between Carlisle Center and Onondaga Formations. Note glauconite with ring.
Figure 32 B: Thin section of MS0503, Plane-polarized view of figure above. 47
Figure 33: Thin section of MS0503 XP, Cherry Valley, contact between Carlisle Center and Onondaga Formations. Chondrites burrow, at center, orienting grains in circular fashion.
Figure 34: Thin section of MS1303 XP, Cherry Valley, contact between Carlisle Center and Onondaga Formations. Zoophycos trace from lower left to upper right. Note orientation of grains in backward “C” fashion, and crack along margin at upper left. 48
Figure 35 A: Thin section of MS1303 XP Cherry Valley, upper contact between Carlisle Center and Onondaga Formation. Upper portion of a dacryoconarid.
Figure 35 B: MS1303, plane polarized view of above figure. 49
Polished Section Descriptions
Cherry Valley, middle to upper Carlisle Center Formation. Quartz siltstone, with abundant glauconite. Figure 36 shows a small vertical burrow within an unbioturbated
lens. This lens has been cut parallel to the long axis of the unbioturbated lens. This lens
also has Zoophycos present on the top surface (top of figure); there are no Zoophycos
traces within the lens. This lens also contains numerous ostracodes and dacryoconarids.
Cherry Valley, uppermost Carlisle Center Formation. Muddy limestone with Chondrites
traces pervasive. Figure 37 shows a small section of Chondrites burrows. No Zoophycos
is present and this section has many more small fossils (ostracodes and tentaculitids).
(Figure 38 is the other side of the same slab shown in Figure 37.)
Cherry Valley, upper contact between Carlisle Center and Onondaga Formation.
Muddy limestone with Chondrites and Zoophycos traces. Figure 39 shows a small
section with Chondrites traces common (right and left of center), with a possible fecal
pellet that was bioturbated, possibly by the Zoophycos or another trace-maker. The dark
area has a concentration of small fossils, including ostracodes, tentaculitids, and a small
brachiopod.
One Zoophycos trace is present; this trace follows along the “S” crack that passes to the
left of the dark area at center. The Zoophycos feeding burrows were made perpendicular
to the plane of the rock slab. The unique aspect of this section is that the Zoophycos 50
Figure 36 A: Unbioturbated lens from Cherry Valley, middle to upper Carlisle Center Formation. Note vertical burrow (oval) and Zoophycos along top of lens (arrow). Centimeter scale.
Figure 36 B: Unbioturbated lens from Cherry Valley, middle to upper Carlisle Center Formation. Note vertical burrow (oval). Centimeter scale.
51
Figure 37 A: Chondrites layer from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations.
Centimeter scale
Figure 37 B: Chondrites layer from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations. Negative and contrast enhanced. Note glauconite grains (red) and Chondrites traces. Scale at center applies to both A and B.
52
Figure 38 A: Chondrites layer from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations.
Centimeter scale
Figure 38 B: Chondrites layer from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations. Negative and contrast enhanced. Note glauconite grains (red) and branching Chondrites trace at center. Scale at center applies to both A and B.
53
Figure 39 A: Fecal pellet from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations. Note bioturbated area at center which may represent a fecal pellet.
Centimeter scale
Figure 39 B: Fecal pellet from Cherry Valley, upper contact between Carlisle Center and Onondaga Formations. Negative and contrast enhanced. Note Zoophycos trace at center indicated by arrow. Scale at center applies to both A and B.
54 made an abrupt course change to either exploit or avoid the dark area at center. The dark area contains a Zoophycos-like trace but it is only found within the dark area. The
Zoophycos animal may be searching using its usual feeding burrows, and when it encounters a nutrient rich area (i.e., fecal pellet) it then exploits that area and later resumes its normal feeding pattern. Alternatively, if the dark area had already been exploited by another trace maker, the Zoophycos trace maker could possibly sense that
the area had been exploited and avoid the area.
Fauna
The paleontology of the Carlisle Center Formation is relatively unknown. The
only previous reference to any fossils are the abundant Zoophycos in this formation. In
this section, I will describe the fossils I recovered and then discuss my interpretations of
the paleoecological implications for the fossils found.
Sponges
Description
Sponge spicule: Cherry Valley, unbioturbated lens, middle to upper Carlisle Center
Formation, float.
Tetraxon spicule from a sponge. Figure 40 shows a spicule with pyrite occupying the
axial canal of one of the points of the spicule.
Interpretation
Several siliceous sponge spicules have been found in the acid washes and in thin
section. There are two types of spicules. One is a straight variety (Figure 24) (monaxon) 55
A
B
Figure 40 A and B: Sponge spicules from Cherry Valley, unbioturbated lens. Two views of same sponge spicule. Note dark pyrite in spicule (arrow). 56 and the other has four axes (Figure 40) (tetraxon, calthrops). Axial canals are present in
both types with pyrite deposited within the canals. It is nearly impossible to identify
sponges by their loose spicules. Some sponges can also incorporate foreign material
(including other spicules and shell material) within their skeletal make up. This incorporation of material also will hinder identification (De Laubenfels, 1955).
Conulariids
Descriptions
Conularia ulsterensis: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation, float.
A cluster of three conulariids, two visible, with rods intact (Figure 41). Partial recrystallization of the calcium phosphate has occurred, resulting in small hexagonal apatite crystals with a reddish-brown color. A third conulariid is hidden within the rock
with only the apical wall visible (Figure 42). The largest conulariid measures 4.3 centimeters long. Using the key provided in Babcock and Feldman (1986), the Conularia ulsterensis identification was reached. The conulariid specimens have a nonreticulate appearance, with more than 40% of the rods abutting at the midline, an inflected circular curve rod articulation style, and more than 39 rods per centimeter. These criteria would identify these conulariids as Conularia ulsterensis. On the same sample, an orbiculoid brachiopod is present. This brachiopod is only half exposed on the rock, but appears to have both valves present, with visible growth lines (Figure 43). The brachiopod and conulariid cluster appear to have a random orientation with respect to each other. Taken with the numerous other unidentifiable shelly fragments on the sample, this jumbled 57
Figure 41 A: Conulariid cluster from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note conulariids. Centimeter scale.
Figure 41 B: Conulariid cluster from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note conulariids. Centimeter scale. 58
Figure 42: Conulariid cluster from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note apical wall upper center. Centimeter scale.
Figure 43: Conulariid cluster from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note orbiculoid brachiopod at center. Centimeter scale. 59 arrangement of specimens may be evidence for a gutter origin for the unbioturbated
lenses (see discussion of unbioturbated lenses). If the cluster of conulariids was
transported as a cluster, they were not transported far. Their arrangement in a cluster, however, may be a random occurrence in which three conulariids ended up in the same gutter.
Possible conulariid: Cherry Valley, unbioturbated lens, middle to upper Carlisle Center
Formation, float.
Possible conulariid preserved in siltstone (Figure 44). Platy calcite is covering most of the specimen, such that positive identification is not possible. Specimen shows semicircular calcium phosphate growth lines/ rods present. Measures 2 centimeters long.
Interpretations
Conulariids are an enigmatic group of extinct animals. They are found from the
Ordovician to the Triassic Periods, and are not uncommon in Paleozoic rocks. They have been tenuously placed in the phylum Cnidaria based on their four-fold symmetry, which is exhibited by other cnidarians, but that is where the similarities end. Conulariids have a general inverted pyramidal shape with a chitinous stalk. Whether all conulariids have a chitinous stalk or this was just one part of their life cycle is up to some debate. Most conulariid fossils are lacking this chitinous stalk or any remnant of the stalk. They also have been found in clusters; therefore, they are thought to be gregarious. Conulariids have a skeleton composed of calcium phosphate. The skeleton has local thickenings that manifest as rods on the outside of each pyramid side (Babcock and Feldman, 1986). 60
Figure 44: Possible conulariid from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation. Note platy calcite at center. Centimeter scale.
Figure 45: Orbiculoid brachiopod from Cherry Valley, unbioturbated lens, middle to upper Carlisle Center Formation.. Centimeter scale. 61
Conulariids have been interpreted as benthic creatures because of the chitinous stalk found attached to a well-preserved specimen (Babcock and Feldman, 1986). In other reconstructions the conulariids have been interpreted as planktonic, much like jellyfish, with their apical end up and tentacles hanging down. In many reconstructions of Ordovician seas in museums and posters, the conulariids are represented in this way.
Brachiopods
Descriptions
Orbiculoid brachiopod: Cherry Valley, unbioturbated lens, middle to upper Carlisle
Center Formation, float.
Small orbiculoid brachiopod preserved in siltstone (Figure 45). Original shell material with circular growth lines preserved. Only convex brachial valve preserved. Measures 2 centimeters across. Figure 46 shows details of the growth lines and unique platy calcite covering the brachiopod. Unique platy calcite is present only on this specimen and the
possible conulariid above; they both are found on the same rock.
Orbiculoid brachiopod: Cherry Valley, lower to middle Carlisle Center Formation, float.
Small partial orbiculoid brachiopod preserved in siltstone (Figure 47). Brachial valve
preserved with annulations. Apex of valve is filled with sediment. Measures 7 mm
across.
Lingulid brachiopod: Cherry Valley, contact between Carlisle Center and Onondaga
Formations, float. 62
Figure 46 A: Orbiculoid brachiopod from Cherry Valley (Detail), unbioturbated lens, middle to upper Carlisle Center Formation. Note growth lines and platy calcite.
Figure 46 B: Orbiculoid brachiopod from Cherry Valley (Detail), unbioturbated lens, middle to upper Carlisle Center Formation. Note growth lines and platy calcite. 63
Figure 47: Orbiculoid brachiopod from Cherry Valley, lower to middle Carlisle Center Formation. Note brachial valve with annulations.
Figure 48: Lingulid brachiopod from Cherry Valley, contact between Carlisle Center and Onondaga Formations. Inarticulate brachiopod in a phosphate nodule. Centimeter scale. 64
Inarticulate lingulid brachiopod preserved in a phosphate nodule (Figure 48).
Annulations are well preserved. Measures 1.5 centimeters long. Nodule has also been extensively bored. Borings are 1-2 mm in diameter.
Articulate brachiopod: Cherry Valley, middle to upper Carlisle Center Formation, float.
Articulate brachiopod in cross section. Both valves present. Measures 3.4 centimeters from umbo to commissure. Preserved in an unbioturbated lens. Figure 49 shows the brachiopod in cross section.
Interpretations
Brachiopods are sessile benthic animals, attached by a pedicle, that filter food from the water column using their lophophore. The articulate varieties compose most of the brachiopods through time. Articulate brachiopods have two valves that hinge together and are thus articulated. Articulate brachiopods have a shell composed of
calcite. Inarticulate brachiopods do not have shells with hinges that articulate and are
only held together by the muscles attached to each shell. Inarticulate brachiopods have a
shell composed of calcium phosphate or calcite. Lingulid brachiopods are one of the few
burrowing species; these brachiopods are typically found in dysoxic brackish water but
can be found in normal oxygen and salinity marine waters. Discinid brachiopods,
including Orbiculoidea, are small inarticulate brachiopods. The pedicle valve is nearly
flat and attaches to a substrate with a pedicle. The brachial valve is conical in shape
(Rowell, 1965). In the Carlisle Center Formation, I find only the brachial valve. It is
possible that the pedicle valve was still attached to the substrate and only the brachial
valve has been transported here. 65
Figure 49 A: Articulate brachiopod from Cherry Valley, middle to upper Carlisle Center Formation. Centimeter scale.
Figure 49 B: Cherry Valley, middle to upper Carlisle Center Formation. Articulate brachiopod in cross section. Centimeter scale. 66
Dacryoconarids
Description
Dacryoconarid steinkern; Cherry Valley, middle to upper Carlisle Center Formation.
Dacryoconarid in Figure 50 shows the teardrop-shaped embryonic chamber and also shows annulations that were within the shell. The specimen figured is an internal mold and preserves the internal features (i.e., annulations) of the dacryoconarid.
Interpretations
In the Carlisle Center Formation there are numerous small (3-4 mm) conical, calcareous fossils. These fossils belong in the class Cricoconarida (Fisher, 1962) an enigmatic but common group of shelly fossils. In thin section and in hand specimen, the fossils appear to have a thin shell with annulations observed on the interior of the shell.
The embryonic chamber at the point of the cone is teardrop shaped. These characters would suggest these fossils belong to the order Dacryoconarida. These fossils also are preserved as internal molds within the samples placed in the acid wash. It is likely that the acid dissolved the carbonate shell, leaving an internal mold of the dacryoconarid
(Figure 50).
Dacryoconarids are thought to be a pelagic variety of cricoconarids because of their thin shells. The order Tentaculitida includes varieties that have thicker, heavier shells and are therefore inferred to be benthic. The tentaculitids are also larger, adding to weight of their shell and probably making them poor swimmers.
67
Figure 50: Dacryoconarid steinkern from Cherry Valley, middle to upper Carlisle Center Formation. Note annulations at upper left and teardrop-shaped embryonic chamber at lower right.
Ostracodes
Descriptions
Ostracode: Shale Pit near Little York, Carlisle Center Formation, float.
Small ostracode with small undulations within shell, with possible brood pouch or crushed valve (Figure 51). Measures 2 mm.
Leperditiid ostracode: Cherry Valley, Carlisle Center Formation, float.
Large leperditiid ostracode preserved in an unbioturbated lens (Figure 52). Some shell material is preserved around the internal mold of the ostracode. Measures 0.8 centimeters long. 68
A
B
Figure 51 A and B: Ostracode from Shale pit near Little York, Carlisle Center Formation. Two views of same small ostracode shell.
69
Figure 52: Leperditiid ostracode from Cherry Valley, Carlisle Center Formation. Note calcite shell around internal mold.
Interpretations
The ostracode fauna of the Carlisle Center Formation has not been described, since it has been generally thought that there are no ostracodes present in the Carlisle
Center Formation (Berdan, 1983). The ostracode fauna of the Rickard Hill Member of the
Schoharie Formation, however, has been described. The fauna includes large
beyrichiaceans and pachydomellids. The paleoenvironment indicated by the ostracodes
and sedimentological evidence would be that of a nearshore, high-energy environment.
The Aquetuck Member was also described by Berdan (1971, 1983), and contains some
24 ostracode taxa, including hollinaceans but no beyrichiaceans. This difference in fauna
is interpreted to mean that the Aquetuck Member was deposited in deeper, quieter water
conditions than the Rickard Hill Member. 70
Through my own fieldwork, I have found that the Carlisle Center Formation in reality contains numerous ostracodes; while most cannot be identified due to the nature of the cements and poor preservation of the shells, one specimen could be identified as a leperditiid, due to its large size (5 mm in length) (Figure 52). These ostracodes are typically found in intertidal or shallow subtidal environments. Leperditiid ostracodes are interpreted as poor swimmers, because of their large size, and as grazers on or burrowers in algal mats (Berdan, 1984). As sedimentological evidence for very shallow conditions and algal mats is absent in the Carlisle Center Formation, I infer that this ostracode was transported. The other ostracodes are smaller in size (1-2 mm in length) and thin-shelled; they are probably pelagic in origin.
Holothurians
Descriptions
Holothurian plates: Cherry Valley, middle to upper Carlisle Center Formation.
These small plates with a reticulate appearance are approximately 0.5 millimeter across
(Figure 54). The plates curve toward the outside, much like a holothurian wheel. The mold in Figure 53 shows this curvature very well. The curve increases in degree toward the outside of the plate.
Interpretations
Holothurians are echinoderms without external plates. Their skeleton is composed of numerous sclerites contained within the skin; this makes the animal very flexible. When the animal dies, the sclerites disassociate from the body and can be transported. The holothurian sclerites are named for their colloquial counterparts, such as 71 wheels, hooks, tables, etc. Holothurians are infaunal and epifaunal deposit feeders, found in deep water, often in muddy sediments and dysoxic conditions. This infaunal feeding characteristic makes the holothurians a possible producer of the Zoophycos trace fossil
(Sprinkle and Kier, 1987).
The objects I am describing as holothurian plates could possibly be interpreted as part of an ostracode because of the reticulate pattern on the outside of the valve of some ostracodes. Reticulated patterns on ostracodes are very common, but the pattern appears to most closely match a holothurian plate or wheel (Gilliland, 1993).
Figure 53: Holothurian plate mold from Cherry Valley, middle to upper Carlisle Center Formation.
72
A
B
Figure 54 A and B: Holothurian plates from Cherry Valley: middle to upper Carlisle Center Formation.
73
Chordates
Descriptions
Fish bone: Cherry Valley, Contact between Esopus and Carlisle Center Formations.
Small bone, possibly a placoderm fish spine. Poorly preserved--some of the bone material has been recrystallized and white calcite fills in pores within the bone (Figures
55 and 56). Measures 2.8 centimeters long. Associated with phosphate nodules and abundant glauconite.
Icriodid conodont: Cherry Valley, middle to upper Carlisle Center Formation.
This conodont (Figure 57) has three rows of denticles with six denticles in each. The posterior process on this specimen has been broken.
Icriodid conodont: Cherry Valley, middle to upper Carlisle Center Formation.
Figure 58 shows a smaller conodont with three rows of denticles with only four denticles in each row. This conodont appears to be complete; in Figure 58 A the basal cavity is shown, appearing to close at the anterior end of the conodont.
Icriodid conodont: Cherry Valley, middle to upper Carlisle Center Formation.
This conodont (Figure 59) is partially exposed from the rock, showing part of the basal cavity and a profile of some of the denticles.
Interpretations
At Cherry Valley, in the Carlisle Center Formation just above the contact between the Esopus and Carlisle Center Formation, a long, porous structure, composed of calcium 74
Figure 55: Fish bone from Cherry Valley, contact between Esopus and Carlisle Center Formations. Note fish bone at center and large amount of glauconite. Centimeter scale.
Figure 56: Fish bone from Cherry Valley (Detail), contact between Esopus and Carlisle Center Formations. Note small grains of recrystallized calcium phosphate around edges of bone. 75
A
B
Figure 57: Icriodid conodont from Cherry Valley, middle Carlisle Center Formation. A: basal cavity of conodont. B: denticle side of conodont. 76
Figure 58: Icriodid conodont from Cherry Valley, middle to upper Carlisle Center Formation. Conodont partially exposed, showing basal cavity.
carbonate and possibly phosphate was recovered (Figure 55 and 56). I interpret this as a fish bone. This fish bone is most likely a placoderm fish spine because of the abundance of the group at this time.
The conodonts collected in the Carlisle Center Formation consist of species of the genus Icriodus. Many of these species are endemic to North America; therefore, their
biostratigraphic utility is limited.
Trace Fossils
Descriptions
Zoophycos apex: Cherry Valley, middle to upper Carlisle Center Formation, float.
Small slab of Zoophycos (Figure 60). Feeding burrows radiate out from lower right of
center to upper portions of the photograph. Axial burrow, if present, would be in the 77
Figure 59: Zoophycos apex from Cherry Valley, middle to upper Carlisle Center Formation. Note feeding burrows radiating from lower center.
lower right of center. Axial burrow is at the highest relief, with feeding burrows
radiating down from it. Measures 10 centimeters across.
Zoophycos bedding plane: Cherry Valley, lower to middle Carlisle Center Formation.
Photo mosaic of fallen block bedding plane. Figure 61 shows the high density of
Zoophycos traces on the bedding planes. Figure 62 shows a single Zoophycos trace
typical of the Zoophycos traces in the Carlisle Center Formation.
Arthropod scratch marks: Cherry Valley, contact between Esopus and Carlisle Center
Formation. 78
Figure 60: Zoophycos bedding plane from Cherry Valley, lower to middle Carlisle Center Formation. Note high density of Zoophycos traces. On photo scale centimeter (left) inches (right). 79
Figure 61: Zoophycos bedding plane from Cherry Valley, lower to middle Carlisle Center Formation. Photo mosaic of two pictures. Note large bowing traces. 80
Probable arthropod scratch marks made into the Esopus sediments and filled with Carlisle
Center sediments. Figure 63 show the crisscrossing pattern of the scratches.
Interpretations
The Zoophycos in the Carlisle Center Formation is very different from other
Zoophycos described in other study areas such as Japan and New Zealand (Ekdale, 1992;
Kotake, 1989, 1990, 1991, 1992, 1993, 1994, 1997). The Carlisle Center Formation
Zoophycos have a much smaller vertical extent in the bedding planes, while the
Zoophycos from Japan and New Zealand have a much larger vertical extent. The New
Zealand and Japan examples of Zoophycos appear to be much more complex with much
more of a helical structure over a much larger vertical distance. This morphology and
vertical extent may be due to the rate of sedimentation in the basin. If each sedimentation
event deposited only a few centimeters or less of sediment, and those layers were then
exploited thoroughly by only one pass, this might produce the single Zoophycos per
bedding plane. On the other hand, if the sedimentation events are larger, depositing a
meter or more of sediment, this would create a package where Zoophycos has
bioturbated. This large sedimentation event would result in an event bed with the base
being unbioturbated and the top recolonized by the Zoophycos. This pattern is not
observed in the Carlisle Center Formation, suggesting low sedimentation rates.
81
Figure 62: Scratch marks from Cherry Valley, contact between Esopus and Carlisle Center Formation. Note complex arrangement of probable arthropod scratch marks at center and left. Centimeter scale.
Figure 63: Scratch marks from Cherry Valley, contact between Esopus and Carlisle Center Formation. Note crisscrossing scratch marks at center. Centimeter scale. 82
THE PALEOENVIRONMENTAL AND PALEOECOLOGICAL SIGNIFICANCE OF
ZOOPHYCOS
Ichnology Background
Ichnology Basics
Trace fossils are the building blocks of ichnology. Trace fossils are biogenically derived sedimentary structures. They often preserve relatively little information on the physical aspects of the organism creating the structure except the relative size of the animal producing the trace.
Trace fossils are useful because they are formed in place, meaning that they usually are not subject to the effects of transportation, like a shell would be. The only problem arises when the rock is exposed and erosion takes place. Then all material that was there would be destroyed. This is a problem in areas where there is periodic sub- aerial exposure such as the intertidal zone. Traces in this zone are least likely to be preserved in the rock record. The periodic ebb and flood of the tides will erase smaller traces and only leave deeper penetrating burrows like Ophiomorpha and Skolithos (Frey and Seilacher, 1980). Trace fossils are also useful for determining the orientation of tilted strata, as most trace fossils are made by animals moving parallel or perpendicular to the bedding of the sediments. Trace fossils can help determine relative sedimentation rates. The basic tenet of this is that if sedimentation rates are high, only smaller, less complex trace fossils will occur, while if sedimentation rates are low, larger, more elaborate structures will be made.
As one goes deeper in the oceans, the preservation potential of trace fossils increases, due to the lessening effects of wind and wave. Also with this deepening, the 83 complexity of the traces increases. The reasoning behind this is that the organisms need to more fully and efficiently exploit the limited food resources of the deeper areas. In shallower areas, the nutrients are so high that only a simple u-shaped burrow, such as
Diplocraterion, is needed to exploit those resources. In deeper areas, because of the reduced nutrient levels, more complex structures are created, such as the complex
Zoophycos feeding trace or the Paleodictyon farming trace (Frey and Seilacher, 1980).
Trace fossils are lumped into several categories based on their inferred function as a burrow or boring. Resting traces (Cubichinia) are shallow traces that indicate an animal came to a stop and sank into the sediment somewhat and then moved on. A classic variety of these is Asteriacites, inferred from its shape to be a starfish coming to rest. Crawling traces (Repichinia) are traces formed when an animal moves on top of the sediment, where their legs make fine scratch marks on their way to somewhere. An example of this is the aptly named Cruziana. Grazing traces (Pascichnia) are traces
formed when the animal moves at or near the sediment water interface (SWI), combing
the surface for food. An example of this type of trace fossil would be Spirophyton.
Feeding structures (Fodinichnia) are thought to be temporary structures where an animal
burrows into the sediment and ingests sediment, then digests the organic material, and
egests the sediment. Examples of these are Diplocraterion and Zoophycos. These traces
are formed in the sediment somewhat similar to underground mining. Dwelling
structures (Domichinia) are formed by animals building simple or branching tubes; often
they are lined with fecal pellets to support the walls. The classic examples of these are
Ophiomorpha and Skolithos. Escape structures (Fugichinia) are made by organisms
responding to a change in sediment depth; in areas of shifting sands, the organisms can 84 become buried and will crawl out of their filled burrows. These structures do not have classic examples, although they occur in event beds and are generally tube shaped (Frey and Seilacher, 1980).
Ichnofacies Concept
Commonly co-occurring trace fossils have led to the creation of an ichnofacies concept. Seilacher pioneered this concept in 1967 (Seilacher, 1967). He was able to lump commonly co-occurring trace fossils into facies. These facies, named for their most common trace fossil, form an ecological gradient from shallow to deep. No specific depths were applied to each of the ichnofacies; they have more general depth zones applied to them, such as the abyssal or subtidal zones. Many of the trace fossils in the ichnofacies overlap into other ichnofacies. Also, many of the trace fossils have changed their ecological zones though time, such as Ophiomorpha and Zoophycos (Bottjer et al.,
1988).
The Zoophycos Trace Fossil
The Zoophycos trace has been the subject of debate for many years about the very
nature of the structure. It is a helical structure in which u-shaped burrows emanate from
an axial vertical burrow (Figure 64). These u-shaped burrows resemble a
Rhizocorallium. These burrows overlaps each other and produce a “cock’s tail” pattern
in the rock. Traditionally, these traces are viewed as formed by animals living in the
sediment and ingesting sediment, digesting the organic material, and then egesting the
sediment. The complex nature of these burrows would suggest mining of the seafloor
because of the time and energy involved in producing such a large burrow (Ekdale,
1992). 85
Figure 64: Development of Zoophycos trace fossil with overlapping u-shaped burrows. Redrawn from Ekdale, 1992.
The Zoophycos trace has been described in rocks from Ordovician to Recent age
(Bottjer et al., 1988). It is likely that the same simple worm has been making the
Zoophycos trace all that time, but it is entirely plausible that other organisms may have
created similar burrow structures over this time (e.g., holothurians; Sprinkle and Kier
1987). Zoophycos has an interesting pattern of occurrences during its history. In
Paleozoic and Mesozoic rocks, Zoophycos can be found in rocks formed in shallow to very deep abyssal environments. In post-Cretaceous rocks, Zoophycos is only found in
slope and deep basinal environments (Bottjer et al., 1988). This change may be due to
the increase of nutrient levels in the deep oceans, triggered by the spreading of the
continents and opening of the oceans during the late Mesozoic, along with the 86 diversification of angiosperms and their detritus entering the oceans. Other ichnogenera also have been found in rocks of this time in areas deeper than their normal ranges (Frey and Seilacher, 1980). Zoophycos is typically found in a low-oxygen environment in post-
Cretaceous rocks. Previous to the Cretaceous, Zoophycos can be found in waters that
range from dysoxic to well oxygenated (Bottjer et al., 1988).
Zoophycos: Two Views
There are two views on how a Zoophycos trace maker makes its burrow. One, put
forward in 1967 by Seilacher, is that the organism resides in its vertical axial burrow and
feeds by either extending tentacles or moving down sub-horizontally making u-shaped or
possibly j-shaped burrows, feeding along the way. This is the traditional view. With this
axial burrow in the middle and overlapping lateral burrows, it is difficult to tell how the
organism making the Zoophycos trace avoided ingesting its own fecal matter. It is
probable that the organism did not feed near its axial burrow, and instead fed in the distal
sediments. This would have reduced the amount of its own fecal material that the
organism ingested, but would also reduce the amount of sediment ingested for nutrient
input, thus reducing the efficiency of the entire burrow.
Another view, put forth by Kotake in 1989 and subsequent papers (1990, 1991,
1992, 1993, 1994, 1997), is that the Zoophycos trace maker was not a deep-burrowing,
deposit-feeding animal. It was a surface dweller eating surface detritus and creating the
Zoophycos burrow as an elaborate sewage dump (Figure 65). This view is supported by evidence from the Upper Pliocene Shiramazu Formation from central Japan, south of
Tokyo. The usual sediments that the Zoophycos trace makers were ingesting were muds, but when there was a volcanic eruption in the area, it created a tuffaceous surface layer. 87
During the tuff deposition, the Zoophycos ingested the tuff sediments on or close to the
SWI and then egested the sediment in the burrow. Portions of the Zoophycos burrow, hence, show the usual mudstone pellets and then portions of the burrow contain tuffaceous pellets. When the tuff sedimentation ceased, the burrows returned to the mudstone pellet fill (Kotake, 1989, 1991).
Figure 65: Kotake view of Zoophycos; black arrow indicates feeding and white arrow
indicates excretion. Redrawn from Kotake, 1990.
The Zoophycos trace maker may use its burrows to deposit fecal pellets so that it
may later harvest the bacteria or fungi that have grown on the pellets. The strategy
behind this is that in abundant times the Zoophycos trace maker deposits an abundance of
material and leaves it to grow, and in lean times the Zoophycos trace maker then harvests
these deposits by re-ingesting the fecal material. This strategy has also been proposed for
specimens from Italy from the Late Cretaceous and Paleocene (Miller and Alberto, 2001).
These specimens have Chondrites-like burrows overlain on a Zoophycos. This may
imply that the Chondrites burrow maker is selectively consuming the Zoophycos food
stores, or possibly that the same trace maker is making both traces (Figure 66). Similar 88
Chondrites-like burrows have been observed in samples from the Carlisle Center
Formation. These are shown in Figure 67.
Figure 66: Development of Zoophycos burrow system: (A) initial burrow development with primary development of helical structure. (B) Complete burrow system, with Zoophycos animal feeding at seafloor and storing fecal material in the burrow spriten. This occurs during abundant nutrient times. (C) The final exploitation and reingestion of stored fecal material in the burrow structure in low nutrient times. From Miller and Alberto, 2001, p. 244.
The Carlisle Center Formation Zoophycos appear to be much more like the traditional view Zoophycos rather than the Kotake view of the Zoophycos. The
Zoophycos I have observed in the Carlisle Center Formation also lack the fecal pellets
that are very common in the Kotake Zoophycos samples and other more recent
Zoophycos samples. This leads me to infer that the Zoophycos in the Carlisle Center
Formation is not the same Zoophycos species as the post-Paleozoic examples.
Size as an Indicator of Environmental Quality
Marintsch and Finks (1978) developed the idea that the size of the trace fossil
directly relates to the size of the animal producing it. As the animal is better fed, it will 89
A
B
Figure 67 A and B: Chondrites-like burrows from Shale pit near Little York, lower Carlisle Center Formation. Note red arrow pointing to Chondrites-like burrows on Zoophycos burrows. Scale in centimeters. 90 become larger and therefore create larger feeding structures. Marintsch and Finks (1978) took measurements of Zoophycos in the Esopus and Pine Hill Formations in the Green
Pond Outlier. They measured the web diameter and the meniscus height of the
Zoophycos trace (Figure 68). They were able to determine that the larger the meniscus height, the larger the web diameter of the Zoophycos.
Figure 68: Diagrammatic sketch of Zoophycos. Measurement of web radius (left) and meniscus height (right). Redrawn from Marintsch and Finks 1978.
There are some problems with using this method. As Zoophycos is a sedimentary structure, it is subject to compaction and diagenetic processes that the rest of the rock experiences. This can create problems with comparison between sections, especially in areas that have been deformed like the Green Pond Outlier. The deformation within a section should be uniform enough to not affect any comparisons within the section. This deformation would especially affect the meniscus heights because increased compaction would potentially shorten the height of the meniscus. Web diameters are not affected as much by deformation unless the entire unit is compressed or extended laterally. 91
Supporting Evidence
Web Radii
Zoophycos web radii give the best measurement of the size of the Zoophycos
traces. These measurements are also the hardest to get data for. Bedding planes must be
exposed to be able to measure the Zoophycos webs. Web radius and meniscus height are
related but a way to determine web radii from meniscus heights has yet to be determined.
Marintsch and Finks (1978) were able to find specimens of Zoophycos with both web
radii and meniscus heights and were able to correlate that the larger the meniscus height
the larger the web radii. A similar correlation with in the Carlisle Center Formation was
not possible because the exposed Zoophycos traces that could be measured weather
quickly and their meniscus height measurements would be suspect.
The web radii measurement of a Zoophycos trace is measured at or near the axial
burrow at the center of the trace outward to the distal areas of the trace. This is shown in
Figure 68. The measurement is represented by the black bar. Measurements were made
in a similar fashion to the Marintsch and Finks (1978) study.
At Cherry Valley, there are two blocks that have fallen from the outcrop. The
larger block has a bedding surface exposed with superb Zoophycos webs exposed. The
web radii measurement data collected from this block was named the large block data set.
The web radii measurements taken from the other smaller block were split into two
groups because the block had split and slid apart. The two sets were named upper and
lower block for their respective position to each other. At a shale pit near Little York,
web radii measurements were taken on exposed rock in the quarry floor and large blocks.
This measurement set is named Shale Pit. At Kingston, Zoophycos web radii 92 measurements were made on a glacially polished surface; the measurement set is named
Kingston. The data for the measurements from the Marintsch and Finks (1978) were taken from histograms provided in the paper. Their measurement data were reported as
Zoophycos web diameter in their histograms; therefore, I divided all their measurement data by two to get the web radius to be comparable to my data. These histograms are reproduced below.
Histograms were generated for each sample showing the distribution of values.
Many of the histograms show a bell curve; this would mean that the population was clustered around the mean size. One can infer that the bell curve would show an adult population, with few small juveniles and few very large adults.
The large block set shows a general bell curve with few small webs and few very large webs. Although the sample size is small, the distribution is fairly even over the entire range. This set contains the largest web radius. The shale pit set also shows a general bell-shaped curve although it is much more constrained. This set has a slightly smaller mean size than the large block set. The upper block set has a very small number of measurements this has lead to the uneven distribution skewed toward the larger values shown in the histogram. The lower block set shows a bell curve, much more than the upper block set. This set is much more like the large block set with mean sizes very close to each other. The Kingston set is very different from the other sets presented so far. In the Kingston histogram the distribution is in a general bell shape but it has been shifted toward the smaller web radius sizes. 93
Large Block mean= 25.7 median= 24.8 n= 22
3.5 3 2.5 t
n 2 u 1.5 Co 1 0.5 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 69: Zoophycos web radii from Large Block, Cherry Valley. Lower to middle Carlisle Center Formation. Shale Pit mean= 23.2 median= 22 n= 39
8 7 6 5 4
Count 3 2 1 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 70: Zoophycos web radii from Shale Pit near Little York. Lower Carlisle Center Formation.
94
Upper Block mean= 20.9 median= 23 n= 14
4.5 4 3.5 3 2.5 unt
o 2 C 1.5 1 0.5 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 71: Zoophycos web radii from Upper Block, Cherry Valley. Lower Carlisle Center Formation. Lower Block mean= 26.6 median= 26 n= 25
3.5
3
2.5
t 2 oun
C 1.5
1
0.5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 72: Zoophycos web radii from Lower Block, Cherry Valley. Lower Carlisle Center Formation. 95
Kingston mean= 15.9 median= 15 n= 185
35
30
25
t 20 n u
Co 15
10
5
0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 73: Zoophycos web radii from Kingston. Upper Esopus Formation.
The units from the Green Pond Outlier all have distributions that are more toward the lower web radius size. Several data sets, including Mountainville unit A, B, Quarry
Hill, and Highland Mills, have very small sample sizes and therefore their uneven distributions are an artifact of this small sample size, although their distributions are all around the smaller web radius size. Mountainville units C and D have roughly bell- shaped curves centered around the smaller web radius size. The Eddyville set has a similar distribution to the Kingston data set with very similar means and medians. The
Woodbury Creek set has a right tailing distribution with many small measurements and few large ones. This data set has the smallest mean size out of all the web radius data sets.
96
Mountainville Unit A mean= 14.0 median=12.7 n= 11
6
5
4
3 Count 2
1
0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 74: Zoophycos web radii from Mountainville Unit A Member, Esopus Formation. Data from Marintsch and Finks, 1978.
Mountainville Unit B mean= 14.3 median= 14.0 n= 16
12
10
8
6 Count 4
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 75: Zoophycos web radii from Mountainville Unit B Member, Esopus Formation. Data from Marintsch and Finks, 1978. 97
Mountainville Unit C mean= 15.1 median= 15.2 n= 34
9 8 7 6 5 4 Count 3 2 1 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 76: Zoophycos web radii from Mountainville Unit C Member, Esopus Formation. Data from Marintsch and Finks, 1978.
Mountainville Unit D mean= 13.0 median= 12.7 n= 43
12
10
8
6 Count 4
2
0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 77: Zoophycos web radii from Mountainville Unit D Member, Esopus Formation. Data from Marintsch and Finks, 1978. 98
Quarry Hill mean= 16.7 median= 17.1 n= 8
4.5 4 3.5 3 2.5 2 Count 1.5 1 0.5 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 78: Zoophycos web radii from Quarry Hill Member, Esopus Formation. Data from Marintsch and Finks, 1978.
Highland Mills mean= 11.0 median=10.8 n= 16
7 6 5 4
Count 3 2 1 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 79: Zoophycos web radii from Highland Mills Member, Esopus Formation. Data from Marintsch and Finks, 1978. 99
Eddyville mean= 16.1 median= 15.2 n= 61
16 14 12 10 8
Count 6 4 2 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 80: Zoophycos web radii from Eddyville Member, Esopus Formation. Data from Marintsch and Finks, 1978.
Woodbury Creek mean= 9.4 median= 8.9 n= 31
10 9 8 7 6 5
Count 4 3 2 1 0 4 8 12 16 20 24 28 32 36 40 44 48 52 Web Radii (cm)
Figure 81: Zoophycos web radii from Woodbury Creek Member, Pine Hill Formation. Data from Marintsch and Finks, 1978. 100
Summary data for each web radii data set are presented in Table 3. On average, the Zoophycos web radii in the Carlisle Center Formation are significantly larger than the
Zoophycos measurements in the Green Pond Outlier. The average size of the Zoophycos
web radii in the main outcrop belt is 22.5 centimeters, while the average size of the
Zoophycos in the Green Pond Outlier is 13.7 centimeters. This is nearly a 10 centimeters
difference. The difference is even greater if the Kingston sample from the Esopus
Formation is removed, leaving only samples from the Carlisle Center Formation with an
average of 24.1 centimeters.
Table 3: Statistical information from web radii samples mean median SD n
Mountainville Unit A 14.0 12.7 3.7 11 Mountainville Unit B 14.3 14.0 2.6 16 Mountainville Unit C 15.1 15.2 4.5 34 Mountainville Unit D 13.0 12.7 3.7 43 Quarry Hill 16.7 17.1 1.7 8 Highland Mills 11.0 10.8 3.0 16 Eddyville 16.1 15.2 4.4 61 Woodbury Creek 9.4 8.9 3.5 31 large block 25.7 24.8 10.3 22 lower block 26.6 26.0 7.6 25 upper block 20.9 23.0 5.9 14 shale pit 23.2 22.0 6.1 39 Kingston 15.9 15.0 4.6 185
T-test comparisons were conducted to compare mean web radii from each
locality. These are presented in Tables 4, 5, and 6. In Table 4 the data sets from the main
outcrop belt are compared with each other. The only significant difference between the
data sets is that the Kingston data set is significantly different from the rest of the data 101 sets in the main outcrop belt. In Table 5 the data sets from the Green Pond Outlier are compared. The Woodbury Creek and Highland Mills data sets are significantly different from almost all of the other data sets. This is due to the small mean size of the measurements in these sets. In Table 6 the main outcrop belt data sets are compared to the Green Pond Outlier data sets. It is obvious that most of the main outcrop belt data sets are significantly different with the exception of the Kingston data set. The Kingston set has the lowest mean web radius in the main outcrop belt, while the Eddyville and
Quarry Hill data sets have the highest in the Green Pond Outlier; this is why there is no significant difference between these sets.
The larger mean size of Zoophycos web radii in the Carlisle Center Formation would lead me to infer that the environment during the deposition of the Carlisle Center
Formation was a much more hospitable environment for the Zoophycos trace-making
animal than the Esopus and Pine Hill Formations. Also the comparison between the
Carlisle Center Formation web radius measurements and the Green Pond Outlier shows
that there is a significant difference in web radius size. 102 103 104
Meniscus Heights
The meniscus height may give the best proxy for the actual size of the Zoophycos trace maker, being that the meniscus height would have been the minimum height of the animal producing the trace. Meniscus height is also most likely to change during compaction or deformation. The meniscus heights are much easier to measure than the web radii. All that is required is an outcrop surface cut perpendicular to the bedding planes. This is why there are many more localities for meniscus heights than the web radii. Unfortunately, the Marintsch and Finks (1978) paper does not contain meniscus height data for each unit at which they measured Zoophycos web radii. Therefore, there will be no comparison between the main outcrop belt and the Green Pond Outlier.
Histograms were generated for each sample showing the distribution of values.
Many of the histograms show a bell curve; this would mean that the population was clustered around the mean size. One can infer that the bell curve would show an adult population, with few small juveniles and few very large adults.
The Kingston sample (Figure 82) has a general bell curve distribution, with a mean of 5.6 mm. This mean meniscus height is somewhat larger than the other samples.
This is somewhat counterintuitive, because the Kingston web radii were much smaller than the rest of the samples from the main outcrop belt. This area has been deformed by folding, which could result in some inflated meniscus height values.
The data sets CVCC 1 thru 6 represent the 1.5 meters of the Carlisle Center
Formation at Cherry Valley, New York. Each numbered unit represents a vertical distance of 25 centimeters within which meniscus heights were measured. The histogram 105 shown in Figure 83 groups the six sets for easier comparison with the other data sets.
This histogram shows a general bell curve distribution.
Another interesting comparison of meniscus heights is between the two Cobleskill
samples (Figures 84 and 85). On the Cobleskill outcrop there is a prominent bed about
25 centimeters thick that stands in relief above the surrounding rocks. The entire outcrop has been thoroughly bioturbated by the Zoophycos trace maker, but there is a half a millimeter difference in the mean size of meniscus height from below the prominent bed to within the prominent bed. This difference may be due to the change in cements during deposition to make the prominent bed more indurated. The change in cements may have made it harder to travel though the sediment and thus reducing the amount of organic material the Zoophycos could ingest.
The shale pit data set histogram (Figure 86) shows a classic bell shaped curve.
The large block data set histogram (Figure 87) shows a bimodal distribution of values.
The large block distribution is also interesting because the large block had one of the
largest web radius mean sizes and the meniscus heights for the same set is the smallest
mean height for all the meniscus heights.
106
Kingston mean= 5.6 median= 5 n= 37
10 9 8 7 6 5 ount
C 4 3 2 1 0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 82: Zoophycos meniscus heights from Kingston. Upper Esopus Formation.
CVCC1-6 mean= 4.6 median= 4.5 n= 63
18 16 14 12 10
ount 8 C 6 4 2 0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 83: Zoophycos meniscus heights from CVCC 1-6, Cherry Valley. Lower Carlisle Center Formation. 107
Cobleskill (Below Bed) mean= 5.1 median= 5 n= 41
12
10
8
6 ount C 4
2
0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 84: Zoophycos meniscus heights from Cobleskill (below prominent bed). Upper Carlisle Center Formation.
Cobleskill (Within Bed) mean= 4.4 median= 4 n= 30
12
10
8
6 ount C 4
2
0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 85: Zoophycos meniscus heights from Cobleskill (within prominent bed). Upper Carlisle Center Formation. 108
Shale Pit mean= 5.0 median= 5 n= 32
14 12 10 8
ount 6 C 4 2 0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 86: Zoophycos meniscus heights from Shale Pit near Little York. Lower Carlisle Center Formation.
Large block mean= 3.6 median= 3.8 n= 28
9 8 7 6 5
ount 4 C 3 2 1 0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 9.5 meniscus height (mm)
Figure 87: Zoophycos meniscus heights from Large Block, Cherry Valley. Lower to middle Carlisle Center Formation.
109
Summary data for each meniscus height data set is presented in Table 7. The large block data set shows the smallest mean height size. This also is somewhat counter intuitive in that the large block data set from the web radius is one of the largest mean sizes, while the same locality has the smallest mean meniscus height.
Table 7: Statistical information on meniscus height samples mean median SD n
large block 3.6 3.8 1.2 28 cvcc1 4.9 5.0 1.1 11 cvcc2 4.6 4.5 1.1 10 cvcc3 3.7 3.0 1.1 10
cvcc4 4.5 4.5 1.1 10
cvcc5 4.6 5.0 1.0 11
cvcc6 5.2 5.0 1.4 11 cvcc1-6 4.6 4.5 1.2 63 Cobleskill below bed 5.1 5.0 1.1 41 Cobleskill within bed 4.4 4.0 1.0 30 shale pit 5.0 5.0 1.0 32 Kingston 5.6 5.0 1.6 37
T-tests were conducted to compare the mean meniscus heights of pairs of data sets. These comparisons are summarized in Table 8. Note that both the large block and the Kingston samples are significantly different than the rest of the sample data sets. The large block has smaller mean heights while Kingston has larger mean heights.
The larger mean web radius data of the large block data set with the smallest meniscus height and the smallest mean web radius data from the Kingston data set with the largest meniscus height would go against the conclusions that Marintsch and Finks
(1978) came to. Their conclusions were that the larger the meniscus height the larger the web diameter. My data do not support their conclusions; in fact, it is in opposition to 110 111
their findings. Marintsch and Finks were able to measure web radii and meniscus heights
of the same Zoophycos trace and then correlate the larger the meniscus height with the
larger web radius. My meniscus height data were collected adjacent to the bedding plane
that web radii were measured. I have no data for specific Zoophycos web radius and
meniscus height. Other factors, including grain size, differential compaction, and
tectonic deformation, would affect the meniscus heights. This may account for the
discrepancy found with the Kingston and large block data sets.
THE PALEOENVIRONMENTAL SIGNIFICANCE OF GLAUCONITE
Glauconite: The Mineral
Glauconite is an iron and potassium-rich hydrated aluminophyllosilicate with a
2:1 layer lattice. Glauconite also contains both ferric and ferrous iron, as a result of the formation process (see below). The amount of iron and potassium varies greatly with the amount of maturity of the crystal. The organization of the grain also varies greatly with
maturity of the grain (Figure 88). Immature or nascent grains have a crystal structure
similar to smectite. These grains are highly disordered and have a high expandable clay
content. The highly mature or highly evolved glauconite grains have a crystalline
structure akin to mica. Their expandable clay content has been greatly reduced and their crystalline structure is much more highly ordered (Lewis and McConchie, 1994). 112
Figure 88: Glauconitization of a granular substrate: glauconite grain evolution from nascent to highly evolved (1-4). Lower portion of figure depicts the estimated time for the grain of glauconite to evolve and its percent potassium content. Redrawn from Odin and Fullagar, 1988, p. 320.
Glauconite: Habits Glauconite’s habits vary with the available materials for nucleation of the grains.
Typically, glauconite is in the form of sand-sized green pellets. The pellets can have cracks related to the internal growth of the crystal. Modern glauconite often nucleates on fecal pellets of marine animals, and also forms on sponge spicules and on foraminiferan tests. Glauconite also forms in the cracks and borings of surfaces such as hard grounds and condensed sections, but these usually occur as films covering a surface. This property of glauconite has led to its use as a paleoenvironmental indicator and as a condensed surface indicator in sequence stratigraphy (Odin and Fullagar, 1988).
Environment of Glauconitization
Microenvironment
Essential to the growth of glauconite is the presence of pore space in the substrate in a semi-confined environment. The degree of confinement determines the amount of 113 mineral-forming reactions that can occur. Ions need to exchange between the seawater and the substrate for the glauconite to form (Odin and Fullagar, 1988).
Glauconite forms at the interface of the reducing interstitial water of the substrate and the oxidizing seawater. This is the reason that both ferric and ferrous iron ions co- occur in glauconite. If the interstitial water becomes depleted of the ions necessary for deposition of glauconite, the reactions will stop. If the grains become exhumed and reburied, the reactions may resume and the grain may continue to mature. If the grains become buried too deeply or the sea level changes sufficiently, the reactions will stop and the grain will stop growing. Hence, low sedimentation rates are required for the genesis of glauconite (Odin and Fullagar, 1988).
The types of pores in which glauconite forms vary depending on the materials available in the environment. The typical place for nucleation is within voids of microfossil tests, fissures in particles, in burrows, or any voids in hard grounds. Coarse
sedimentary particles are only glauconitized on the outside surfaces because the grain’s
interiors are too confined to deposit glauconite (Odin and Fullagar, 1988).
Geographic Environment
Latitude does not seem to be a controlling factor in the production of a glaucony,
as modern glaucony are produced from Cape Horn to the Caribbean Sea. Although most
glaucony appear to occur on a topographic high near a deep sea basin, glauconite is
produced on both stable margins and tectonically affected areas (Odin and Fullagar,
1988). 114
Depth does seem to be a controlling factor in the genesis of a glaucony. Modern glaucony occurs between 60 and ~1000 meters in depth. Any shallower and the seawater may be too oxidizing to produce glauconite (Odin and Fullagar, 1988).
Glauconite and Sequence Stratigraphy
The presence of a glaucony facies has been traditionally regarded as indicative of a transgressive systems tract. This is generally true, because of the tendency of the transgression to trap sediment on the continent. The sea level rise allows for the materials that would normally be deposited in depths too shallow for the glauconite to form to be within the critical depth to produce a glaucony. Condensed sections and hard grounds commonly also have glauconite present on those surfaces. Glauconite has also been described in lowstand system tracts and rarely in highstand system tracts.
Glauconite can also be reexhumed or disturbed by bioturbators. These glauconite grains may be ingested and incorporated into fecal pellets, and then permit the creation of a new generation of glauconite on those fecal pellets (Odin and Fullagar, 1988; Stonecipher,
1999).
A major change in sea level is not a requirement for the genesis of a glaucony.
For instance, if there were a die-off of foraminifera in an area and those tests just happened to settle in the critical depth, this would allow for the formation of glauconite within the tests (Odin and Fullagar, 1988).
Glauconite in the Carlisle Center Formation
The glauconite present in the Carlisle Center Formation is of the evolved stage
(Figure 88). These grains have a lumpy outward texture. The grains also have a green color, but are not the very dark green that would indicate the highly evolved state. These 115 observations, lumpy shape, and dark green color would classify these glauconite grains as evolved. The glauconite grains also depict rings of lighter colored glauconite around a darker glauconite nucleus (Figures 18, 31, and 32). This feature could indicate a relict grain of glauconite that has grown new glauconite on the outside or possibly the pore fluids changed their composition and changed the glauconite being formed.
Glauconite in the Carlisle Center Formation occurs in abundance at the underlying and overlying contacts. In between, glauconite is present but not in abundance. This would mean that the conditions for glauconite creation were present in the formation during the entire time deposition was occurring. The reason for the change in abundance would most likely be a change in sedimentation rates from lower near the lower contact to higher in the middle of the formation to again lower at the upper contact.
The large amount of glauconite would indicate that the Carlisle Center Formation would be a transgressive systems tract. This is in agreement with the interpretations of
Ver Straeten and Brett (1995), in which they describe the Carlisle Center Formation as a transgressive systems tract with the Aquetuck and Saugerties Members of the Schoharie
Formation as being the highstand systems tract in this depositional sequence.
DISCUSSION
Preservational Biases
The Carlisle Center Formation has a depauperate, low-diversity assemblage of fossils. There appears to be a higher concentration of phosphatic skeletal elements, but there are some carbonate fossils in the unit. This higher concentration of phosphatic skeletal elements could indicate that the carbonate skeletal material was preferentially 116 dissolved. If there were a carbonate preservational bias in the Carlisle Center Formation, there would be molds of carbonate fossils within the formation, but no shelly material.
This is not observed in the unit. In fact, there are concentrations of small carbonate fossils in the unbioturbated lenses in the Carlisle Center Formation, including ostracodes,
tentaculitids, and rare small brachiopods. This would indicate that the carbonate shelly material was not present, except in unbioturbated lenses, or the carbonate material was
dissolved before sedimentation occurred and a mold could be made.
Zoophycos in the Carlisle Center Formation directly reduces the preservation
potential of any fossil within the formation. As the Zoophycos trace maker moves
through the sediment, it is connected to the oxygenated ocean waters above through its
central burrow and feeding structures. This will bring oxygen down into the sediment
and increase the activity of microbial decomposers, allowing for the decomposition of
any organic matter in the sediment before fossilization can occur.
The grain size of the formation is also important for preservation potential. As
grain size increases, the porosity increases, allowing for the infiltration of oxygenated
ocean waters, which would increase the activity of the decomposers. This is evident in a
comparison of the pyrite content of the Esopus and Carlisle Center Formations. Pyrite
formation requires at least dysoxic conditions and dissolved iron and some organic matter
to form (Benchley and Harper, 1998). In the Esopus Formation, a shale, there are
abundant large pyrite nodules and iron staining on outcrops (Figure 15). In the Carlisle
Center Formation, a siltstone, there are no pyrite nodules. This is probably due to the
larger grain size and not Zoophycos, since both formations contain Zoophycos that would
introduce new oxygenated waters into the sediment. 117
Paleoenvironment
Unbioturbated lenses
In the Carlisle Center Formation, there are small lenses of unbioturbated material
(unbioturbated in the sense of not being processed by Zoophycos; small burrows may still be present, however). These lenses tend to be linear in shape (longer than they are wide).
They tend to be small, with sizes ranging from 10 to 25 centimeters wide and 15 to 40 centimeters long. These lenses were found in the float washed down from the outcrop.
They tend to break along the boundary between the unbioturbated area and the bioturbated area on the outside, and also break along possible joints, where later fluid flow has deposited calcite. These lenses are also the most fossiliferous areas of the entire formation, containing numerous ostracodes, tentaculitids, holothurian plates, sponge spicules, rare conulariids, and rare small articulate brachiopods.
Within some of the unbioturbated lenses, small vertical burrows are present.
These structures must have been made when the unbioturbated lens was a soft sediment feature. There are Zoophycos present on the top of these lenses, but they do not enter the lens. Therefore, the top of the lens was soft sediment when the Zoophycos trace was made on the top of the lens.
The unbioturbated lenses found within the Carlisle Center Formation are typically found weathered out of the outcrop because of the higher cohesiveness of the material within the unbioturbated lenses than the surrounding rock. The unbioturbated lenses erode out because of the presence of the Zoophycos traces in the surrounding rock and the instability that the Zoophycos trace creates. Cracks develop along the outside of the unbioturbated lenses, which then simply fall out of place within the outcrop. 118
These lenses have two possible origins, as concretions and as gutter casts. In this section, I will discuss the origin of both structures and the evidence from the Carlisle
Center Formation for these two interpretations.
On the Origin of Gutter Casts
A gutter cast is an erosional feature where a usually fine-grained cohesive substrate is eroded in a fashion to produce a trough. These troughs are then filled in with sediment, often of larger grain size. These deposits are usually associated with tempestite-forming events. The gutter cast can also contain tool marks and shell lags.
Gutter casts have also been associated with pot holes, much like the glacially derived pot holes in terrestrial environments, but made in a fully marine environment. Often the gutter casts are found perpendicular to the shore line, which would show that the storm created a unidirectional current moving offshore, similar to a rip current (Myrow, 1992).
Gutter casts have been described from nearshore to deep-water submarine fans (Pérez-
López, 2001; Myrow, 1992). This range of settings may indicate that some other sedimentary structures have been lumped into the general “gutter cast” category; the actual environmental range of the gutter cast may be somewhat smaller (Browne and
Myrow, 1994).
The model proposed by Myrow (1992) uses a helical flow to generate the required erosive force to produce a gutter. The sediment transported by the current bypasses the usual proximal depositional areas and is deposited in the deeper distal areas. When the flow has been reduced in speed, the gutters are then filled in by material transported by the flow. The steep sides of the gutters would indicate that the gutters were filled rapidly, as otherwise the sides would have slumped into the gutter. Hummocky stratification and 119 oscillation ripple marks have been observed within the gutter fills. These features would indicate that there were storm conditions at the time of deposition (i.e., tempestite)
(Myrow, 1992).
The presence of only gutter casts and pot hole casts would indicate a temporary lowering of storm wave base during an especially strong storm, creating the necessary erosive current action to produce the gutters. The areas just below storm wave base would not feel the effects of the oscillations from the waves (e.g., hummocky stratification), but the downslope currents would erode and deposit in the affected areas.
Although in the Carlisle Center Formation there are no tempestite deposits, the
Zoophycos traces may have amalgamated the sediments so as to destroy the hummocky cross-stratification of a typical tempestite. No hummocky cross-stratification has been observed in the Carlisle Center Formation.
In the Carlisle Center Formation, the unbioturbated lenses do not exhibit the typical tool marks found in gutter casts in other areas (e.g., Myrow, 1992). This may be due to the fact that there were no tools to make the marks. Although there are fossils present in the lenses, they are too small and fragile to create large tool marks. Therefore, the lenses have a relative smooth outer surface.
On the Origin of Concretions
Concretions are very common secondary sedimentary structures. Concretions can form in any type of substrate but are most common in sandstones and shales. These structures are typically found in marine rocks. Carbonate concretions are formed in the sulfate reduction zone in the unlithified sediments near the sediment water interface
(SWI). In this zone, concretions form when some type of organic nucleus is buried past 120
(i.e., deeper than) the oxic and several metal reduction zones and lingers in the sulfate reduction zone. Here, in alkali conditions, the precipitation of carbonate can occur around the organic material. All of these reactions occur before compaction; therefore, these concretions are lithified before the surrounding sediments. This creates an interesting juxtaposition of bedding to the concretion; bedding will often bow around the concretion. Fossil preservation is also often much better within concretions than the
surrounding sediments. Concretions typically are lenticular or spherical in shape and
vary in size from three centimeters to three meters in size.
In the Carlisle Center Formation, the unbioturbated lenses do not exhibit the
typical shape of a concretion. These lenses are longer than they are wide, with fairly
parallel long sides. I have not observed the entire extent of these lenses to see if they are longer than 40 centimeters. Within the lenses, there are concentrations of calcareous fossils, which may be enough nucleating material to form the concretion. A concretion does not explain the abrupt contact with the outside bioturbated material with no apparent bowing of bedding (i.e., Zoophycos) around the unbioturbated lens or any original bedding within the unbioturbated lens.
Paleogeographic Trends
Large-scale unbioturbated lenses only occur at the Cherry Valley outcrops. One
small (5 centimeters across) unbioturbated lens was found at the shale pit locality near
Little York (21 kilometers east), but nowhere else. The unbioturbated lenses are only
found in float from the middle to top of the Carlisle Center Formation. It would be
understandable not to find the lenses at the shale pit locality because only the lower to
middle Carlisle Center Formation is present. At the Cobleskill locality, the middle to 121 upper Carlisle Center Formation is present, but no unbioturbated lenses were found there.
This would lead me to surmise that the Cherry Valley area was shallower than the shale pit or Cobleskill localities, assuming the lenses are gutters, because a shallower environment would be subject to more forces, such as storm waves. In a deeper environment, there would be little or no effects from storm events.
Zoophycos and Their Relation to the Unbioturbated Lenses
Within the Carlisle Center Formation, Zoophycos is present adjacent to several unbioturbated lenses but does not enter the lenses themselves. It is uncertain why the
Zoophycos animal did not enter the lens. There are two possibilities. The first is early
cementation of these areas, possibly as a concretion. This position is bolstered by a
concentration of fossils within the lenses. The relative absence of fossils outside the
lenses may be an artifact of the Zoophycos animal bioturbating the outside material
around the lens and digesting any small animals there, or encouraging pore water
movement that would dissolve shelly debris. It is possible that the fossils present in the
lenses were protected from dissolution because of the early cementation, and the fossils
outside the lenses were exposed to more dissolving waters and were not preserved. If the
lenses were cemented when the Zoophycos animal was feeding in the sediment, we would
see an abrupt change in burrow direction when the animal bumped into the lens;
however, this is not observed. This sort of abrupt change in direction has been observed
in other areas of the formation but not in relation to any lenses (Figure 39).
The second option is that these lenses are gutter casts. In this case, the presence
of Zoophycos adjacent to the lenses would just be an artifact of the down-cutting of the
current into preexisting Zoophycos structures. The Zoophycos would show no course 122 changes in the sediment to avoid the lens because the lens was created after the
Zoophycos bioturbated the area.
Conclusions about the Unbioturbated Lenses
These unbioturbated lenses appear to be gutter casts. The key evidence for this is the burrows within the lenses showing that these were soft sediment features and the
Zoophycos traces on top of the lens further proving that the lens was soft at the time of deposition. The Zoophycos adjacent to the lens is an artifact of the down-cutting of the gutter.
Apparent Water Depths
If these unbioturbated lenses are in fact gutter casts, this implies that the depositional environment of the Carlisle Center Formation is definitely below fair weather wave base and possibly at or just below storm wave base (50 to ~100 m in restricted epeiric seas). Alternatively, the Zoophycos trace makers may have homogenized the sediments to disrupt any tempestites that may have been formed during storm events. In this case the depth would be above storm wave base. It is also possible
that this area is well below the normal storm wave base and these unbioturbated lenses
represent a rare intensification of storm energy, like a super storm that only forms once a
millennium.
Zoophycos is also an indicator of water depth. Zoophycos is typically found in
marine waters between the storm weather wave base and areas where turbidity flows
dominate (50 m to deep basinal depths). The typical range for Zoophycos traces to occur
tends to be an outer shelf environment. 123
Glauconite is a good an indicator of water depth. When the conditions are right within the pore spaces in the sediment, glauconite typically will form in waters between
60 and 1000 meters. Glauconite will not form above 60 meters. Since glauconite is found throughout the Carlisle Center Formation, it is likely that the formation was deposited no shallower than 60 meters.
Taking all of the evidence as a whole, a depth range between 60 and 100 meters seems most reasonable. This depth range is not unreasonable for a shallow epeiric sea.
CONCLUSIONS
The Esopus and Carlisle Center Formations were deposited in a shallow epeiric sea. The Carlisle Center Formation was deposited below storm wave base but not out of
reach of storm currents that would form gutters. The underlying Esopus Formation was
deposited in a deeper setting out of the effects of storm events, except at the much more
shallow Green Pond Outlier (e.g., tempestites in Highland Mill Member).
These environments, during the deposition of the Esopus and Carlisle Center
Formation, were not devoid of life during this time. Besides the abundant Zoophycos traces found throughout these units, there are abundant ostracodes, dacryoconarids, conodonts, inarticulate brachiopods (lingulids, and orbiculoids), sponge spicules, holothurian plates, fish bones, gastropods, and conulariids represented in at least one the formations studied. These fossils may not be in situ, but they were in the area or the fossils were simply concentrated in the gutter casts by storm currents. There is a preservational bias for calcium phosphate and against calcium carbonate outside the gutter casts in the Carlisle Center Formation. 124
The Zoophycos size can be used in determining the preferred ecological zone of the Zoophycos trace-makers. Using the thought that a larger Zoophycos would be a
happier more well fed animal and therefore live in a better overall environment, the
Zoophycos from the main outcrop belt would have been in a better environment than the
Zoophycos in the Green Pond Outlier. There are some limitations of using this method,
since the Zoophycos traces are part of the rock and are subject to the same forces as the
rest of the rock. However, there are advantages to using this method as well, because the
traces are made in situ (they are not transported) and thus directly reflect the
paleoenvironment of the formation.
Overall the Esopus and Carlisle Center Formations deserve more attention.
Further work may include determining the orientation of gutters to determine paleostorm
current directions. The ostracode and conodont faunas need to be thoroughly
documented to better place this interval biochronologically. Further use of the
Zoophycos web radius size in other areas, in conjunction with other techniques, may be useful in determining the paleoenvironment.
REFERENCES CITED
Babcock, L.E., and Feldmann, R., 1986, Devonian and Missississippian conulariids of
North America. Part A. General Description of Conularia: Annals of Carnegie
Museum, v. 55, p. 349-410.
Banks, H.P., Grierson, J.D, and Bonamo, P.M., 1985, The flora of the Catskill clastic
wedge: in Woodrow, D. L., and Sevon, W. D., eds., The Catskill Delta.
Geological Society of America Special Paper, v. 201, p. 125-141. 125
Brenchley, P.J., and Harper, D.A., 1998, Palaeoecology: Ecosystems, Environments, and
Evolution: Chapman & Hall, London, 402 p.
Berdan, J., 1971, Some ostracodes from the Schoharie Formation (Lower Devonian) of
New York: in Dutro, J., ed., Paleozoic perspectives: A Paleontological Tribute to
G. Arthur Cooper: Smithsonian Contributions to Paleobiology, v. 3, p. 161-174.
Berdan, J., 1983, Biostratigraphy of Upper Silurian and Lower Devonian Ostracodes in
the United States: in Maddocks, R., ed., Applications of Ostracoda: Department of
Geosciences, University of Houston University Park, Houston, Texas, p. 313-337.
Berdan, J., 1984, Leperditicopid ostracodes from Ordovician rocks of Kentucky and
nearby states and characteristic features of the order Leperditicopida: U. S.
Geological Survey Professional Paper 1066-J, p. J1-J40.
Bottjer, D., Droser, M., and Jablonski, D., 1988, Paleoenvironmental trends in the history
of trace fossils: Nature, v. 333, p. 252-255.
Boucot, A. J., 1982, Ecostratigraphic framework for the Lower Devonian of the North
American Appohimchi Subprovince: Neues Jahrbuch fuer Geologie und
Palaeontologie, Abhandlungen, v.163, p. 81-121.
Boucot, A.J., Gauri, K.L., and Southard, J., 1970, Silurian and Lower Devonian
brachiopods, structure, and stratigraphy of the Green Pond Outlier in Southeastern
New York: Palaeontographica. Abteilung A: Palaeozoologie-Stratigraphie, v.135,
p. 1-59.
Browne, G. H. and Myrow, P. M., 1994, Pot and gutter casts from the Chapel Island
Formation, Southeast Newfoundland: discussion and reply: Journal of 126
Sedimentary Research, Section A: Sedimentary Petrology and Processes, v. 64, p.
706-709.
Boucot, A. J., and Rehmer, J., 1977, Pacificocoelia acutiplicata (Conrad, 1841)
(Brachiopoda) from the Esopus Shale (Lower Devonian) of eastern New York:
Journal of Paleontology, v. 51, p. 1123-1132.
De Laubenfels, M.W., 1955, Porifera: in Moore, R.C., ed., Treatise on Invertebrate
Paleontology: Part E Archaeocyatha and Porifera, Geological Society of America,
Boulder, p. E 22-E 110.
Ekdale, A. A., 1992, Muckraking and mudslinging; the joys of deposit-feeding: in West,
R. R., and Maples, C.G., eds., Trace Fossils. Short Courses in Paleontology, v. 5,
p. 145-171.
Faill, R. T., 1985, The Acadian Orogeny and the Catskill Delta: in Woodrow, D. L., and
Sevon, W. D., eds., The Catskill Delta. Geological Society of America Special
Paper, v. 201, p. 15-37.
Fisher, D.W., 1962, Small Conoidal Shells of Uncertain Affininites: in Moore, R.C.,
Treatise on Invertebrate Paleontology: Part W Miscellanea, Geological Society of
America, Boulder, p. W 98-W 141.
Fisher, D.W., 1979, Devonian stratigraphy and paleoecology in the Cherry Valley, New
York Region: in Friedman, G.M., ed., Joint Annual Meeting of New York State
Geological Association Meeting Guidebook 51st annual meeting and New
England Intercollegiate Geological Conference 71st annual meeting Guidebook, p.
21-45. 127
Frey, R., and Seilacher, A., 1980, Uniformity in marine invertebrate ichnology: Lethaia,
v.13, p. 183-207.
Gilliland, P.M., 1993, The skeletal morphology, systematics and evolutionary history of
holothurians: Special papers in palaeontology 47: Palaeontological Association,
London, 147 p.
Goldring, W., and Flower, R., 1942, Restudy of the Schoharie and Esopus Formations in
New York State: American Journal of Science, v. 240, p. 673-694.
Howell, B.F., 1942, New localities for fossils in the Devonian Esopus Grit of Ulster
County, New York: New York Museum Bulletin, v. 327, p. 87-93.
Johnson, J.H., 1957, The Schoharie Formation: a redefinition: Unpublished Ph.D.
dissertation, Lehigh University, 178 p.
Johnson, J.H., and Southard, J.B., 1962, The Schoharie Formation in southeastern New
York: New York State Geological Association Annual Meeting Guidebook 34:
New York State Geological Survey, Albany, p. A7-A23.
Koch, W.F., 1996, Atlanticocoelia, new Lepocoeliid (Brachiopoda) genus from the
Devonian of Eastern North America: Journal of Paleontology, v.70, p. 1088-1090.
Kotake, N., 1989, Paleoecology of the Zoophycos producers: Lethaia, v. 22, p. 327-341.
Kotake, N., 1990, Mode of ingestion and egestion of Chondrites and Zoophycos
producers: Journal of the Geological Society of Japan, v. 96, p. 859-868.
Kotake, N., 1991, Non-selective surface deposit feeding by the Zoophycos producers:
Lethaia, v. 24, p. 379-385.
Kotake, N., 1992, Deep-sea echiurans: possible producers of Zoophycos: Lethaia, v. 25,
p. 311-316. 128
Kotake, N., 1993, Tiering of trace fossils assemblages in Plio-Pleistocene bathyal
deposits of Boso Peninsula, Japan: PALAIOS, v. 9, p. 84-91.
Kotake, N., 1994, Population paleoecology of the Zoophycos-producing animal:
PALAIOS, v. 9, p. 84-91.
Kotake, N., 1997, Ethological interpretation of the trace fossil Zoophycos in the
Hikoroichi Formation (Lower Carboniferous), southern Kitakami Mountains,
Northeast Japan: Paleontological Research, v. 1, p. 15-28.
Lewis, D.W., and McConchie, D., 1994, Practical Sedimentology: Chapman & Hall, New
York, NY, 213 p.
Liebe, R.M., and Grasso, T., 1990, The Devonian Stratigraphy of Cherry Valley, N.Y.:
Northeastern Geology, v. 12, p. 7-13.
Linsley, D.M., 1994, Devonian paleontology of New York; containing the brachiopods,
bivalves, rostroconchs, gastropods, tergomyans, ammonoids, trilobites,
eurypterids and phyllocarids, based on the lithographs of James Hall and John
Clarke: Paleontological Research Institution Special Publication, 21, 472 p.
Marintsch, E. J., and Finks, R. M., 1978, Zoophycos size may indicate environmental
gradients: Lethaia, v. 11, p. 273-279.
Marintsch, E. J., and Finks, R. M., 1982, Lower Devonian ichnofacies at Highland Mills,
New York and their gradual replacement across environmental gradients: Journal
of Paleontology, v. 56, p. 1050-1078.
Miller, M.F., and Rehmer, J., 1982, Using biogenic structures to interpret sharp lithologic
boundaries: An example from the Lower Devonian of New York: Journal of
Sedimentary Petrology, v. 52, p. 887-895. 129
Myrow, P.M. 1992. Pot and gutter casts from the Chapel Island Formation, southeast
Newfoundland: Journal of Sedimentary Petrology, v. 62, p. 99-115.
Odin, G.S., and Fullagar, P.D., 1988, Geological significance of the glaucony facies: in
Odin, G.S., eds., Green Marine Clays: Developments in Sedimentology, v. 45,
Elsevier, Amsterdam, p. 295-332.
Olivero, D., and Gaillard, C., 1996, Paleoecology of Jurassic Zoophycos from south-
eastern France: Ichnos, v. 4, p. 249-260.
Pérez-López, A. 2001, Significance of pot and gutter casts in a Middle Triassic carbonate
platform, Betic Cordillera, southern Spain: Sedimentology, v. 48, p. 1371-1388.
Rickard, L.V., 1975, Correlation of Silurian and Devonian Rocks in New York State:
New York State Museum and Science Service Map and Chart Series, (New York
State Geological Survey), no. 24.
Rowell, A.J., 1965, Inarticulata: in Moore, R.C., ed., Treatise on Invertebrate Paleontology: Part H Brachiopoda, Geological Society of America, Boulder, p. H260- 296. Seilacher, A., 1967, Bathymetry of trace fossils: Marine Geology, v. 5, p. 413-428.
Sprinkle, J., and Kier, P.M., 1987, Phylum Echinodermata: in Boardman, R.S., ed., Fossil
Invertebrates: Blackwell Science, Cambridge, MA, p. 550-613.
Stanley, G.D. Jr., and Teichert, C., 1976, Lamellothoceratids (Cephalopoda,
Orthoceroidea) from the Lower Devonian of New York: University of Kansas
Paleontological Contributions v. 86, 14 p.
Stonecipher, S.A., 1999, Genetic characteristics of glauconite and siderite: Implications
for the origin of ambiguous isolated marine sandbodies: in Bergman, K.M. and
Snedden, J.W., eds., Isolated Shallow Marine Sand Bodies: Sequence 130
Stratigraphic Analysis and Sedimentologic Interpretation: SEPM Special Paper
no. 64, p. 191-204.
Ver Straeten, C.A., and Brett, C., 1995, Lower and Middle Devonian foreland basin fill in
the Catskill Front: Stratigraphic synthesis, sequence stratigraphy, and the Acadian
Orogeny: in Garver, J.I., and Smith, J.A., eds., New York State Geological
Association Annual Meeting Guidebook 67: New York State Geological Survey,
Albany, p. 313-356.
Ver Straeten, C.A., and Brett, C., 2000, Bulge migration and pinnacle reef development,
Devonian Appalachian Foreland Basin: Journal of Geology, v. 108, p. 339-352.