University of Nevada

Reno

Paleoecology of Upper Triassic Bioherms in the

Pilot Mountains, Mineral County,

West-Central Nevada

A tiles is submitted in partial fulfillment of the requirements for the degree of Master of Science

in Geology

by

Diane Elinor Cornwall

May 1979 University of Nevada

Reno ACKNOWLEDGEMENTS

I would like to thank Dr. James R. Firby for his supervision, support and for his guidance through those difficult "rough spots."

Dan Howe was a constant source of interesting ideas and enthusiasm, especially during the early stages of the thesis project. Throughout my research Fred Gustafson and I worked together, he always being an interested and understanding coworker and friend throughout the lonely weeks of research. Dr. Joseph Lintz, Jr. was invaluable in his assistance in procurement of materials and equipment and in his unselfish desire to solve any problem. I thank Dr. Mead for joining my committee. I greatly appreciate those hearty souls who ventured out into the desert with me and braved the hazards and extremes; these include Barbara Foster, Mickie Dunn, Micheal Judge and my parents who spent all their vacations in my field area. I would also like to acknowledge the moral support given by my parents, special and other friends.

i n ABSTRAC

In the Pilot Mountains, Mineral County, Nevada, up to five horizons of bioherms are present within the top 76 meters of the lower member of the Upper Triassic (Karnian) Luning Formation. These bio­ herms are located in the carbonate portions of small terrigenous- carbonate rhythms.

The biohermal mounds, less than 15 meters high^exhibit four of

Wilson's (1975) seven facies. Mound formation was mainly autogenic.

Four stages of Walker and Alberstadt's (1975) biological succession are recognized. The dominate organisms are sphinctozoans, corals and spongiomorphids, supported by pelecypods, brachiopods, crinoids, echinoids and gastropods.

The mounds formed in moderately shallow, quiet warm euhaline waters in a slowly subsiding area of slow sedimentation and changing terrigenous sediment sources. TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS ...... iii

ABSTRACT...... iv

LIST OF FIGURES, TABLES, AND P L A T E S ...... viii

INTRODUCTION ...... 1

Introduction to Reefs of the Triassic Period ...... 1

Location ...... 3

Purpose, Scope, and Limitations ...... 5

Methods of Investigation ...... 5

Previous Investigations ...... 6

GENERAL GEOLOGY OF THE PILOT MOUNTAINS ...... 9

Geologic Setting ...... 9

Structure ......

Stratigraphy ...... 1°

Luning Formation ...... 14

Lower Member...... 14

Regional Geologic History ...... 15

CINNABAR AND DUNLAP CANYON BIOHERMS ...... 19

FACIES...... 23

Lopha Basal Pile...... 24

Bindstone Facies ...... •

Sponge-Trichites Bindstone Subfacies ......

Coral-Spongiomorphid Bindstone Subfacies ...... 26

Thecosmilia Bafflestone ...... 26

Coral Framestone...... 27

Interreef Facies ...... 28 VI

Page

Crinoid Flanking Facies ...... 29

Gryphaea Facies ...... 30

Other Pelecypod B e d s ...... 30

Cavity and Fissure Fillings ...... 31

Black Calcilutite...... 32

Lithoclastic Breccia ...... 32

Shale and Argillite B e d s ...... 33

PALEOAUTECOLOGY ...... 34

Porifera...... 34

Sclerosponges ...... 37

C o r a l s ...... 39

Superfamily Thamnasteriodidea Alloiteau, 1952 ...... 40

"Thamnasteria" ...... 40

Thecosmilia...... 42

Other Colonial Corals...... 4 3

Montlivaltia ...... 43

Brachiopods...... 44

Mollusca...... 46

Bivalvia...... 46

Oysters ...... 46

Gryphaea...... 46

Lopha...... 47

Pinnidae...... 48

Pinna...... 48

T r i c h i t e s ...... '...... 48

Cephalopoas...... 49 V l l

Fage

Gastropods...... 51

Echinoderms...... 51

Echinoids...... 51

Cidaroids...... 51

Crinoids...... 53

Vertebrates...... 53

PHYSICAL PALEOSYNECOLOGY ...... 56

Water D e p t h ...... 56

Light Conditions...... 58

Radiation...... 58

Temperature of Water ...... 59

Shape of Water Body and Geomorphology of the Land Surface and

Sea F l o o r ...... 59

Water Movement...... 59

Bottom Sedimentalogical Conditions and Sedimentation Rates . . 60

MOUND SYNECOLOGY...... 62

Morphology...... 65

Diversity...... 69

Maturity...... 69

Size...... 69

Associations ...... 71

Predation...... 71

CONCLUSION...... 73

SYSTEMATIC PALEONTOLOGY ...... 75

SELECTED REFERENCES ...... 118

APPENDIX I 133 v ii i

Page

APPENDIX ! I ...... 135

PLATES ...... 136 LIST OF FIGURES, TABLES, AND PLATES

Figure Page

1. Location Map of Dunlap and Cinnabar Canyons ...... 4

2. Structure Map of Dunlap and Cinnabar Canyons ...... 12

3. Cross Section Across Dunlap and Cinnabar Canyons ...... 13

4. Stratigraphic Section of Balloon Canyon ...... 16

5. Comparison of Triassic and Holocene Coral Borings ...... 41

6- Biological Diagrams of Mounds ...... 63

7. Mound Locality M a p ...... 64

8 . Coral and Spongiomorphid Growth Forms ...... 66

9. Comparison of Triassic and Jurassic Mound Morphology . . . 67

10. Continuation of Figure 9 ...... 68

11. Bahaman Reef Morphology ...... 70

12. Fossil Localities ......

Table

1. Bivalve Living Habit and Trophic Level ...... 50

2. Distribution and Abundance of Organisms in Dunlap and

Cinnabar Canyons ...... 55

Plate

1. Pamiroseris...... 136

2. Margarastraea...... 136

3. Astrocoenia, Montlivaltia, Elyastraea ...... 136

4. Pelecypods ...... 136

5. Pelecypods...... 137

6. Brachiopods...... I37

7. Juvavites, Cidarid spines, Sclerosponges ...... ] 38

ix INTRODUCTION

INTRODUCTION TO REEFS OF THE TRIASSIC PERIOD

Carbonate buildups of the Triassic, show some of the characteris­ tics of the Permian paleoreefs and evolve other characteristics which are still prevalent in modern reefs. Knowledge of the characteristics of the

Triassic carbonate buildups has increased greatly in the last few years.

The majority of Triassic bioherms did not form into true wave resistant reefs but formed on shallow protected platforms (Bosellini. and Rossi,

1974, p. 209). The latitudinal extent of Upper Triassic (Norian) reefoid bodies is between 10 S to 60 N (according to modern continental configuration). Though these buildups are widely distributed, they display a remarkable similarity to each other, more so than other build­ ups do in any later period.

The oldest hermatypic scleratinian corals, already diversified into six families, appeared in banks of Middle Triassic Anisian and

Ladinian ages in the German southern Alps, Corsica and Sicily. Middle

Triassic Ladinian European buildups were distributed in the same areas.

These Middle Triassic bioherms were not coral dominated. In the

Bundsandstein of Northern Germany, serpulid worms formed buildups

(Haack, 1921, in Heckel, 1974) . Mounds of pelecypods and brachiopods formed in the Muschelkalk (Gwinner, 1968). The Middle Triassic atoll­ like buildups in Northern Italy were over 910 meters thick with well developed flanking beds and the reefoid biota included calcareous algae, crinoids, molluscs, foraminifera, and a few scleractinids (Bosellini and Rossi, 1974). Banks were built up within the Ladinian Wetterstein limestone in which the dominate community member was Tubiphytes (a tiny 2 delicate encrusting animal), while sponges dominated the megafauna

(Ott, 1967) .

An extension of faunas as well as a greater number of species is evident in the Upper Triassic. As colonizing corals become more dominant, the spongiomorphids also played a more important role. Euro­ pean Upper Triassic reefs occur in southern and southeastern Europe.

Within the border region between Austria and Germany, a barrier reef formed between the carbonate shelves and the basinal facies. This is known as the Dachstein reef complex, which is 1230 meters thick in certain areas. Calcisponges and scleractinids are the major constitu­ ents dominating the central area of the reef complex composed of patch reefs and detritus. Detritus and calcilutite make up the fore-reef, and rounded skeletal sand with dasyclad algae make up the back-reef

(Wilson, 1975) . The Rheatian Steinplatte reef complex has facies similar to the Dachstein complex, but with slightly different faunal constituents (Ohlen, 1959).

Three forms of organic buildups can be found in the Upper

Triassic of the Old World, these are: gently sloped margins with reef knolls of corals and spongiomorphids (exemplified by the Hohe G511 buildups above Berchtesgaden in Bavaria); true sharp reef rims like those at Steinplatte, and bioherms surrounded by shale as in the Kossen

Formation.

Besides the famous European occurrences, Upper Triassic buildups are also present in the U.S.S.R., Greece, the Middle East, southeast

Asia and Malaysia.

In the New World carbonate buildups occur along the Pacific con­ tinental margin in Peru, Nevada, California, Idaho, Oregon, British 3

Columbia and Alaska. Only one occurrence has any great lateral or vertical extent, an Oregon locality (George Stanley, personal communi­ cation, 1976). The New World bioherms range in age from Ladinian to

Rheatian.

In Nevada there are biohermal occurrences in the Augusta Moun­ tain Formation, New Pass area (Ladinian), the upper member of the Prida

Formation of the Star Peak Group in the Humbolt Range (Karnian) and in the Karnian Luning Formation in the Garfield Hills, Gillis Range, Gabbs

Valley Range, Cedar Mountains, west Shoshone Mountains and the Pilot

Mountains. In the Shasta area of California within the "Hosselkus"

Limestone, there are extensively recrystallized and silicified corals and spongiomorphids, but there is little evidence of any original build­ ups. The Pacific Coast buildups form mostly into shoals, banks, mounds, and patch reefs of small dimensions which exhibit poor organization.

LOCATION

The bioherms of the lower member of the Luning Formation are located about seven miles east of Mina, northwestern Pilot Mountains,

Mineral County, Nevada, Township 6 N, Range 36 E, Longitude 118°00' W and Latitude 38°25' N. Both Cinnabar and Dunlap Canyons extend through the biohermal area (fig. 1). The elongated pod chosen for the study area is 3.2 kilometers long in the east-west direction and .9 kilometers wide in the north-south direction. The topographic relief is about 769 meters and the elevation varies from 1692 meters to 2153 meters. The area is accessible all year round via two unpaved roads; one of which passes through Cinnabar Canyon and the other through Dunlap Canyon. Figure 1 5

PURPOSE, SCOPE, AND LIMITATIONS

Through various lines of investigation I have attempted to reconstruct the paleoecologic system of the lower member of the Tuning

Formation. The various lines of investigation include: (1) a descrip­ tion of the facies, (2) faunal taxonomy, (3) general stratigraphic and structural relationships, (4) paleoautecology of the faunal elements,

(5) paleosynecology of the faunal communities and of the facies and

(6) a literature search for recent and ancient analogs.

A main limitation in this type of investigation is the number of avenues of research which can be effectively utilized in a short time span with a limited amount of materials and equipment. Research was hindered by the complex structures within a small area, recrystalli­ zation of the limestones and consequent poor preservation of the fossils.

Time did not permit the investigation of other correlative bioherms located in the immediate area.

METHODS OF INVESTIGATION

The first phase of the investigation includes finding the limits of the biohermal occurrences, determining the stratigraphic and struc­ tural relationships and locating the individual bioherms. Representa­ tive fossils are collected from each locality. The bioherms are then analyzed for biological succession, lithologic changes, taxonomic con­ stituents, percentages of dominant species and other paleoecologic relationships. Each bioherm group is compared to other bioherms litho­ logically and biologically. Photographic slides are taken of the various mounds, projected on graph paper and the arrangement, distribu­ tion, and density of the fossils is then analyzed. 6

Lithologic samples are taken of each possible facies at each locality, then are described and analyzed. Insoluble residues, acetate peels, polished sections, thin sections and Alizarin Red stain were used to assist in the interpretation of the facies.

Polished sections, thin sections, acetate peels and acetic acid residues are also used in the search for microfossils.

The base map is Nielsen's geologic map used in his dissertation

(1964). The localities were first mapped from air photographs BLM N-03E

FY 67 5-172 and BLM N-03E FY 67 5-238 that were enlarged nine times.

The carbonate classification schemes used in this paper are those of Embry and Klovan (1971) and Folk (1962) . Age determinations are based on ammonites and other short range biota. Reef terminology used in this paper can be found in Appendix I. Localities and specimens have UNMSMM numbers and locality locations and descriptions can be found in figure 11 and Appendix II.

From June 1973 to March 1977, 81 days were spent in the field completing field investigations and rechecking field data.

PREVIOUS INVESTIGATIONS

Previous investigations of the northern Pilot Mountains have been made of the general geology, structure, stratigraphy and paleon­ tology.

The first investigator, H.W. Turner (1902, p. 267), stated that

the Pilot Range is composed of Jurassic rocks on the basis of fossil

content (which was later found to be Triassic). He drew the first diagrammatic cross section of the area.

J.E. Spurr (1905) described the volcanic and sedimentary rocks of the Pilot Mountains. He believed the Star Peak and Koipato Formations of the West Humbolt Range to be correlative. The Pilot

Mountains were then still considered to be Jurassic.

J.P. Smith (in Spurr, 1905, p. 104) dated the corals as Jurassic and younger. In 1912, Smith assigned the corals to the Norian inter­ regional coral zone.

The structure of the area was first described by H.G. Ferguson

(1924) while working with Cathcart and others on the reconnaissance geology.

Stanton (1926) recognized two separate fossil faunas in the

Pilot Mountains and his knowledge of faunas assisted the other workers in the subdivision of the complex Jurassic and Triassic sedimentary rocks.

Smith (1927) described several genera and species of reef build­ ing organisms, recognized the buildups and again assigned these to the

Norian stage.

W.F. Foshag (1927, p. 115) compiled a geologic map of the Pilot

Mountains and described the stratigraphy as related to the quicksilver deposits.

S.W. Muller (1929 and 1930) did his Master's thesis on the

Gabbs Valley Range and his Ph.D. dissertation on the Pilot Mountains.

Most of his work deals with ammonites and other fauna commonly used for age dating. Muller (1936) published a paper on the bioherms themselves, which is one of the basic papers used in this present study. His con­ clusions brought out several ideas including the following: (1) the corals are Karnian, not Norian, (2) corals of the Triassic resemble the

Jurassic corals, (3) there is little morphologic change in the corals from the Middle Triassic to the end of the Triassic and (4) reef corals 8

are not generally useful for correlation purposes. Also his paper-

described the major species involved in the bioherms.

Muller and Ferguson (1936 and 1939) described the Mesozoic

stratigraphy of the Hawthorne and Tonopah quadrangles. They named the

Luning Formation, described the various units in the area and included

detailed maps. Muller and Ferguson (1949) presented what is still the definitive work on the structure.

Nielsen (1964) expanded Muller and Ferguson's work in his dis­

sertation. The formational names and some of the structure were changed.

The Gold Range Formation was proposed for parts of the Luning, Dunlap

and Excelsior Formations. Most of his study concentrated on the petrol­ ogy of the igneous rocks of the Pilot Mountains and vicinity. GENERAL GEOLOGY OF THE PILOT MOUNTAINS

GEOLOGIC SETTING

The Pilot Mountains are located in a ■structurally complex area within the Basin and Range province. The Walker Lane fault zone is parallel and to the west of the Pilot Mountains. The Walker Lane is a large wrench fault with enechelon fault alignment and strike-slip dis­ placement of some segments (Gilluly, 1977). From Permian to Recent time, these mountains have undergone episodes of deformation including major episodes of thrusting and folding. There have been periods of extrusive and intrusive activity since the Permian. Permian, Triassic,

Jurassic and Cenozoic strata are exposed in the area.

STRUCTURE

In the late Triassic the southern portion of the Pilot Moun­ tains, consisting of Permian strata, was strongly deformed. These exposures are tightly folded with west-trending hinge lines and axial surfaces dipping steeply to the south. In the northern Pilot Mountains, the Upper Triassic rocks occur in thrust plates and have folds which, have gently plunging west-trending axes and axial planes dipping steeply north. Lower Jurassic rocks are found between the Triassic and Permian rocks. These are the least deformed and dip to the north gently, or are found in broad open folds. The Upper Triassic and early Lower

Jurassic rocks are deformed in the later part of the early Jurassic during a long interval of folding and thrusting. Superimposed on Meso­ zoic structure are Late Tertiary normal and strike-slip faults and local deformation adjacent to igneous intrusions (Nielsen, 1964).

9 10

There are as many interpretations of the thrust faulting as there have been structural investigators in the Lower Luning area.

Therefore, the interpretations may be tenuous. The major thrust through the study area is the East Ridge fault which is considered by Muller and

Ferguson (1949) to be caused by a later second episode of thrusting. Of these later thrusts the East Ridge fault has the greatest magnitude and carried the Luning Formation southward. The bioherms occur on both the upper and lower plate of the thrust. Small normal faults having small displacements can be found throughout the area. Bedding plane slippage is also common. There are synclines, anticlines, superimposed folds and segments of thrust faults in the Cinnabar and Dunlap Canyons (fig.

2, 3).

The Pilot Mountains are sliced into blocks by Pre-Tertiary northwest trending faults with maximum strike-slip displacement on the magnitude of 20 kilometers. Lateral faulting probably began late in the Miocene and continued into the Recent (Nielsen, 1964).

STRATIGRAPHY

Basically there are three sequences, the Permian (?) andesite tuff and chert of the Excelsior Formation, shallow marine Upper Triassic and Lower Jurassic rocks (epeirogenic facies), and subaerial and marine

Upper Triassic and Lower Jurassic coarse rocks (orogenic facies)

(Nielsen, 1964) .

The Permian Excelsior Formation occupies the southern portion of the Pilot Mountains and occurs in small thrust wedges in the northwest­ ern part of the range. This formation consists essentially of dark massive chert, fine-grained silicified tuff interbedded with coarser tuff and some dark tuffaceous sandstone. Greenstone, greenstone breccia 11 and felsite are present in places and usually underlie the chert and tuff. The minimum estimate of total thickness is 3,300 meters.

The epeirogenic facies consists of the Luning Formation, Gabbs

Formation, Sunrise Formation and part of the Dunlap Formation. The

Luning Formation is discussed in the next section. The Upper Triassic-

Lower Jurassic Gabbs Formation, which does not crop out in the Pilot

Mountains, and the Lower Jurassic Sunrise Formation consist of thin- bedded slaty limestones and slates. The thickness of the Sunrise

Formation is 200 to 266 meters in Mac Canyon. Locally unconformably overlying the Sunrise Formation is the Dunlap Formation (Lower Jurassic) which consists of sandstones, silts, shales and limestones. The thick­ nesses are highly variable and this part of the Dunlap Formation is usually thin.

The orogenic facies contains the middle member of the Luning

Formation conformably overlain by the Gold Range Formation which is unconformably overlain by part of the Dunlap Formation. The Gold Range

Formation is 1670 meters thick in Telephone Canyon in the Pilot Moun­ tains. The lower part of the formation consists of chert pebble con­ glomerates, breccias, and argillites. There are minor amounts of shale, tuffaceous limestone, fine-grained sandstone and sandy limestone.

The volcanic portion contains rhyolite tuff, andesite tuff breccia, tuffaceous argillite and flows. Most of the Dunlap Formation consists of fanglomerates and conglomerates made up of limestone and dolomite pebbles from the upper member of the Luning Formation. The thickness may be as much as 1600 meters. Superimposed fold with angle of plunge Lithologic contact Syncline

Thrust of reverse fault, hachures on Anticline overthrust side Steeply dipping faults Luning Fm.

Faults with uncertain trace QT Tertiary and Quaternary Sea le 1 26 cm = 3 22m rocks Structure map of Cinnabar and Dunlap Canyons. From Nielsen (1964). to Ta Tertiary andesite breccia fault ftla Conglomerate and argillite-Luning ■ extension of fold kl I Lower member of Luning Fm. Scale 1.26cm = 322 m

Figure 3. Crossection across Dunlap and Cinnabar Canyons, N 22° W. From Nielsen's section C to C' from the structure map (1964).

00 14

Luning Formation

Exposures of the Luning Formation, named by Muller and Ferguson

(1936, p. 245), are widespread in eastern and central Mineral County.

The northern slopes of the Pilot Mountains is the designated type- locality. Other exposures are present in Garfield Hills, Gillis Range,

Cedar Mountains, Paradise Range, Gabbs Valley Range and the western

Shoshone Mountains.

•Thickness and lithology vary greatly from range to range and even show variation within the same range. No complete section has been found, but the most complete section crops out in the Pilot Mountains where 2580 meters is exposed. This is divided into three informal members by Muller and Ferguson (1936): a lower limestone member about

1000 meters thick, a clastic member about 1,000 meters thick and an upper limestone member about 645 meters thick. Neither the base nor the top of the formation is exposed in the Pilot Mountains. The Luning

Formation sediments are marine and include volcanic, clastic and car­ bonate rocks. The Upper member consists essentially of limestone with subordinate dolomite and minor interbedded slate and argillite. The top of the member is buried under Tertiary volcanic rocks.

The middle member contains argillites, slates and conglomerates composed of chert pebbles from the Excelsior Formation to the south.

Towards the south, the conglomerates becomes more prevalent. The con­ glomerate forms almost half of the middle member in Cinnabar Canyon.

Lower Member

The lower member of the Luning Formation is predominately thinly bedded grey and buff-colored, silty and shaley limestone, with inter­ calated multicolored shales. The shales can be light brown, light to 15

dark grey or reddish to purple. The unit exposed in Cinnabar and Dunlap

Canyons is composed of terrigenous-carbonate rhythms with alternations

averaging six to ten meters of shale and carbonates.

The terrigenous part of the cycle contains beds of shale or shale

with argillites in sharp contact with the carbonates (fig. 4). Figure 4

shows the variations in thickness and the pattern of the rhythm. Near

conformable contacts with the middle member, the terrigenous beds become

thicker and the argillites become more common. Also some red fossilif-

erous limy argillites of the middle member can be found near the con­

tacts with the lower member.

The bioherms are concentrated in the top 76 meters of the lower member on the lower plate of the thrust, but the bioherms are not

exactly in the same stratigraphic position on the upper plate. Accord­

ing to Muller (1936) the coral beds are middle or more likely early

Kamian in age based on mollusks and brachiopods found in and above the

reefoid strata.

REGIONAL GEOLOGIC HISTORY

During most of the Permian period the area was low lying and

tectonically stable. Following the Sonoma orogeny in Western Nevada, volcanism resumed in the Late Permian through the early Early Triassic resulting in the accumulations of the Diablo sequence over the Antler orogenic belt. The Diablo sequence is primarily marine deposits

(Silberling and Roberts, 1962) . The bioclastic limestones and corals

interbedded with coarse clastic and tuffaceous rocks suggest that the

Diablo sequence was laid down in a near-shore shallow marine environ­ ment (Nielsen, 1964, p. 71). Lower and Middle Triassic rocks are rare

17

or lacking at the margin of the Luning Embayment and thus the area was

low lying and stable as in the Permian. The area was either emergent

or an area of shallow marine deposition (Nielsen, 1964). During the

Late Triassic and Early Jurassic an epicontinental sea extended inland

over northwest and west-central Nevada and most of California. The

Luning Embayment (an east-trending bight in the margin of the seaway)

was a gradually subsiding offshore basin of deposition during this time.

The southern margin of the basin received coarse elastics and volcanic

rocks (subaerial and submarine), which were associated with orogenic

activity (Nielsen, 1964).

Intense folding of the Permian rocks was caused by slumping or

gravity gliding of bedded chert and tuff from the elevated southern

margin northward into the basin of the Luning Embayment during the Late

Triassic. A great fan of sedimentary breccia and conglomerate accumu­

lated at the base of the foldbelt and was soon covered by ignimbrites,

tuff breccia, andesite and rhyolite flows, erupted from vents along the

crest of the vertical uplift (Nielsen, 1964). Shelf deposits of the

"Luning sequence" post-date emplacement of the Golconda thrust sheet

and may have been the source for the chert detritus that makes up the

thick conglomerate part of the sequence (Silberling, 1973, p. 355).

Triassic seas advanced eastward and southeastward across western Nevada

(Nielsen, 1964). Throughout the middle and late Triassic and possible early Jurassic, the Antler orogenic belt was intermittently a local

source of clastic debris for the flanking areas. The fine-grained terrigenous sediment deposited into the Mesozoic seas of western Nevada must have been transported across the orogenic belt from the continen­ tal area further east and southeast (Silberling and Roberts, 1962). 18

With the gradual subsidence, deltarc deposits (fine-grained terrigenous material) invaded from the east and interfingered with shelflike cal­

careous and shaley deposits (Silberling and Roberts, 1962). The sea

transgressed into an area with appreciable topographic relief in the

Kamian. Further transgression took place in the Late Kamian into the

eastern part of the embayment and local irregularities diminished allow­

ing more limestone and dolomite to form (Silberling, 1959).

Lower Jurassic folding began with the development of a linear basin parallel to the southern margin of the Luning Embayment which received Lower Jurassic Dunlap sediments. A second vertical uplift near the present Gabbs Valley Range occurred, causing folding and thrusting. At first this was minor with structural troughs filling with Luning sediments and Dunlap sediments. The thrusting movement was southward. The uplift continued causing warping and deflecting with the continued thrusting and folding. Volcanism was contemporary with the uplift (Muller and Ferguson, 1949) (Nielsen, 1964).

Late Mesozoic-Early Tertiary superimposed folding and faulting may be related to the emplacement of the Sierra Nevadan batholith a few miles to the west. Large open folds formed in response to this late episode of folding. Intrusives were emplaced in the area during this time. The latest episode of volcanic activity was in the Late Miocene

(Nielsen, 1964). Tertiary and Quaternary faulting was normal, strike- slip and lateral. CINNABAR AND DUNLAP CANYON BIOHERM3

Cinnabar and Dunlap Canyon carbonate buildups or bioherms can

be more specifically referred to as mounds. Mounds are defined by shape

only and thus are equidimensional or elipsoidal. Mounds are further

recognized by their shared characteristics. They are usually of small

dimensions, are typical of quiet-water environments, and consist of

detrital, poorly sorted bioclastic biomicrite with minor amounts of organic boundstone. Many mounds, developed on shelves and in shallow basins, show a vertical and lateral sequence of textural and organic

facies.

The extrinsic, mainly hydrologic, controlled processes are rapid. These extrinsic processes of mound development and succession are described by Wilson (1975). Wilson also describes the typical mound facies in regards to their intrinsic and extrinsic controls.

Intrinsic changes operate within the mounds' organic communities.

Creation of and competition for substrates by reef dwellers helps cause an ecologic succession in ancient reefs from Ordovician through

Cretaceous age are discussed by Walker and Alberstadt (1975).

J.L. Wilson, in Carbonate Facies in Geologic History, p. 367,

1975, lists the mound processes:

1. Mechanical accumulation of both fine and coarse sediment through current and wave action. Probably the most important process localizing mound growth. 2. Trapping and baffling of carbonate sediment produced locally at higher than normal rates. Probably this is the most important process contributing to the growth of the mound. 3. Stabilization of sediment by surface encrustation so that normal processes of marine erosion do not remove it. 4. Protection by a veneer or wall of frame-building organ­ isms at a late stage in its development. 5. Protection by cementation. In lime mud deposited and remaining in the marine environment, cementation is very slow.

19 20

In shallow water banks, where chances of subaerial exposure is better, lithification of lime mud is more effective.

Processes 1, 2, and 3 are operative in the building of the

Cinnabar and Dunlap Canyons mounds.

Seven common facies are found in mounds, these are: the basal

bioclastic wackestone, the micritic bafflestone core, the crestal

boundstone, the organic veneers and fissure filling, the flanking beds,

talus and the capping grainstones (Wilson, 1975, p. 367-368). Four of

these facies are found within this study's mounds.

The basal bioclastic wackestone pile which is infrequently

exposed, consists of shells stacked one upon another. Commonly these

are oyster or oyster-like shells. The role of this facies is to help

stabilize the bottom for other organisms. It is presumed that these

shells are heaped up by gentle currents from the surrounding area

(Wilson, 1975, p. 367). But the possibility of in situ pile forming

from successions of living oysters cannot be ruled out.

The micritic bafflestone core is present, but it does not fit

completely into the general pattern Wilson observed. This facies normally occupies the thickest part of the mound, but in the Cinnabar and Dunlap Canyon mounds it is a narrow biostromal bed not found in all the.mounds. The dominant organism of this bafflestone will exclude other biota, and this certainly seems to be the case in the study area.

Thecosmilia is the common worldwide bafflestone former in the late

Triassic and is present in these mounds. The role of this facies is the trapping or baffling of fine limey sediments; Thecosmilia is able to accomplish this because of its dendroid form and upright growth habit (Wilson, 1975). 21

Flanking bed facies which flank the sides of the mounds include

the interreef facies and the crinoid flanking facies. The flanking beds

measure at least twice the volume of the mounds, which suggests only

slight subsidence (Wilson, 1975).

Talus beds composed of lithoclastic debris are rare in the study

area. The low energy involved in the mound processes could not form

these beds and the processes that form these mounds are yet unknown

(Wilson, 1975).

Kenneth Walker and Leonard Alberstadt (1975) developed a four

stage biological reef succession which can be applied to the Cinnabar and Dunlap Canyons' mounds. Succession is controlled by water depth and tectonic controls, but as is the case with many reefoid bodies "the regularity in reef formation resulted from intrinsic control, in particular the gradual alteration of the substratum by organisms and elaboration of energy-flow pathways as the community develops" (Walker and Alberstadt, 1975). Whether the' control is intrinsic or extrinsic causes the succession to be autogenic or allogenic respectively and this is often difficult to decipher from fossil reefs. The developmen­ tal stages are the stabilization (pioneer) stage, the colonization stage, the diversification stage and the domination stage (ibid.).

The stabilization zone contains organisms which stabilize the soft substrate. Organisms associated throughout reef history with this stage are pelmatozoans, with subordinate branching algae, bryo- zoans, corals and sponges. In the Triassic, pelecypods were commonly the dominate organism involved in this stage. Wilson states that the shells could have been piled up by the currents, thus making this stage allogenic, but normally this zone is autogenic. Lopha is the dominate 22 element in the shale and calcilutite matrix pelecypod piles in Cinnabar and Dunlap Canyons.

The colonization stage contains reef building organisms having encrusting and branching forms. This part of the succession is not clearly defined in the study area, but it probably includes the sponge—

Trichites bindstone and the bedded Thecosmilia bafflestone.

Commonly the diversification stage contains organisms of higher taxonomic levels, is highly diverse, comprises the bulk of the bioherm and is considered autogenic (Walker and Alberstadt, 1975). East of

Mina this zone is the coral-spongiomorphid bindstone, which comprises the bulk of the mound, but lacks the normal diversity and higher taxo­ nomic levels.

In the study area the domination zone rarely develops. The study area localities are very much like the Walker and Alberstadt's model; in that the diversity is lessened so only a few species are dominant which are corals usually.

These poorly developed tiny mounds of Cinnabar and Dunlap

Canyons follow the general patterns set up by Wilson, Walker and

Alberstadt for the vast variety of reefs and mounds throughout the history of carbonate buildups. are at least seven easily recognized carbonate facies that are named on

the basis of their position and role, if related to the mounds, and

their lithology and fossil content. Other beds and lenses are impor­

tant, but lack sufficient exposures of homogeneity to be considered a

separate facies. The terrigenous beds can be easily grouped into one

of two facies on the basis of lithology.

The field descriptions include the geometry of the reef bodies,

composition, stratigraphy, fossil content, position in the area and

bounding lithologies. The microscopic description includes textures,

composition, microfossils, the fossils relationship to the matrix, and

the interpretation.

The seven carbonate facies include the Lopha basal pile, the

bindstone facies including sponge-Trichites bindstone subfacies and a

coral-spongiomorphid bindstone subfacies, the coral framestone, the

Gryphea beds, the interreef facies, the Thecosmilia bafflestone and the

crinoid flanking lenses. The two terrigenous facies are the shale beds

and the argillite beds. Other beds include the worm bioclastic beds,

the bioclastic pelecypod beds, a lithoclastic breccia, and a black

calcilutite.

The limestone matrix is quite homogeneous and consists of a

calcilutite with some fine silt included. The silt has very fine

quartz fragments with few one or two millimeter quartz crystals, angular

fragments, or rounded grains of quartz. Rare tiny pyrite crystals are

found in the carbonate facies. Other minerals such as gypsum are present but were not specifically tested for and their percentages can

23 24

not be estimated. Calcite veining is common in most of the facies.

The fossils and matrix are partially to totally recrystallized. The

matrix contains "ghosts" of detrital grains, and drusy calcite fills

the interiors of brachiopods and other biota. Most of the sparry cal­

cite is probably not primary and the matrix may have originally had a

good percentage of micrite, which was subsequently recrystallized.

The micrite which is still found in the rocks is black colored and

found in small amounts in all the carbonate facies. Sometimes the

micrite forms envelopes around fossils and grains or is randomly dis­

persed throughout the matrix. The limestones of lesser purity contain

more black micrite.

The accuracy of the insoluble residue studies used in the

lithology descriptions is only within five percent. The fine grained

nature of the carbonate rocks rendered the staining procedures ineffec­

tive.

LOPHA BASAL PILE

These piles are not usually exposed. This (dark gray) very

friable limy shale is full of Lopha or similar oyster-like shells.

At locality UNMSMM004-G the associates include spirifers, Gryphaea,

Trichites, and Pamiroseris. The total thickness of the beds is unknown

because the base is never exposed, but ten centimeters to three meters

is exposed in three localities.

The matrix is composed of two separate components, a black shale

with minor tan colored silt-size grains and a tan and gray calcilutite.

Recrystallized fossils are sometimes impinged by the matrix, and layers of pelecypod shells support the rock. The fossils make up 60 percent of the rock of which 3 percent are brachiopods, one percent are crinoid 25 ossicles and tiny echinoid spines and all the rest are Lopha, Gryphaea, and other oyster-like pelecypods. The insoluble residue was 45 percent of the rock. Considering the high fossil content, the matrix has only a small amount of limestone. The rock is a limy pelecypod shale.

These accumulations of shells were very important in forming a firm base for the harder substrate dwellers.

BINDSTONE FACIES

The bindstone facies contains two subfacies which are divisible on the basis of position in the succession and fossil dominants. Essen­ tially both the facies contain the same species which have the same morphologic forms.

Sponge-Trichites Bindstone Subfacies

Sponge-Trichites bindstone is found above the basal pile as part of the colonization stage. Above the sponge-Trichites bindstone is either the Thecosmilia bafflestone or the other bindstone facies. Out­ side of the mounds, this facies is found as thin beds between terrige­ nous beds or near Gryphaea or other pelecypod beds. The biota found in this subfacies includes Pamiroseris, Trichites, calcisponges, colonial and solitary corals, spongiomorphids, crinoids, echinoids, pectens, and brachiopods.

The rock has as much as 50 percent fossils in a tan or less commonly gray matrix. The matrix is an unsorted finely recrystallized calcilutite. Planispiral, and low and high spiraled gastropods less than two millimeters in length are uncommon or rare. 26

Coral-Spongiomorphid Bindstone Subfacies

This bindstone subfacies is different from the other subfacies

in several respects which require close examination. The coral heads

and more of the coral species are present. Sponges are un—

common, but spongiomorphids are more common. Each mound contains a

percentage of this subfacies. Some outcrops contained approxi-

mately 40 percent matrix. The coral—spongiomorphid bindstone is grey

to blue-gray in color and has less tan silt within the matrix than the

other bindstone. In most mounds this subfacies represents the highest

zone of the ecologic succession attained which is the diversification

stage. Commonly bioclastic floatstones or interreef beds cap these

mounds. Found beneath this subfacies is either the other bindstone or

the bafflestone facies.

The calcilutite is in part finely recrystallized. Almost all

the fossils are recrystallized.

THECOSMILIA BAFFLESTONE

The Thecosmilia bafflestone appears cream colored to light gray with dark gray corals on the outer surface. The matrix is a gray calci­

lutite and cavities filled with a tan silty calcilutite. Iron staining

is visible in fractures. Fresh surfaces are medium gray, recrystallized and show very little internal structure. The beds can be continuous for

46 meters or more. The 0.3-1.0 meter beds occur once in the mound sequence and not in all mounds. Found below the beds usually is the sponge-Trichites bindstone or the Lopha basal pile. Above the bed the coral-spongiomorphid bindstone can be found. The UNMSMM006-C locality bioherms have bafflestone beds that are surrounded in shale. The 27

individual oval shaped heads, 15 to 20 centimeters high, are surrounded

by 2.5 or five centimeters of shale on all sides.

The matrix, 30 to 60 percent of the rock, is a silty unsorted

calcilutite with some possible micrite. The majority of the matrix is

recrystallized to a granular mosaic. There are very few microfossils,

all which are gastropods. Rarely, one centimeter in diameter brachio-

pods are found between the corallites. About 15 or 16 percent of the

rock is insoluble residue.

CORAL FRAMESTONE

The matrix of the coral framestone appears grayish-tan or cream

colored and the cavity fillings are a tan silty calcilutite. The fossils within the matrix appear blue-gray. The corals and spongiomorphids are usually subspherical, averaging 30 centimeters in diameter. This facies has undergone the greatest amount of recrystallization, due to the high density of corals. Stratigraphically above either the interreef facies or a dark pelecypod bioclastic bed is found. Below this facies, the bindstone facies is always present. The facies is lenticular,

UNMSMMO07YA locality is four meters high and 12 meters long and 6 or more meters wide. Important associated remains include solitary corals, branching spongiomorphids, and broken Trichites. Rarer elements include terebratulids, spirifers, gastropods (high spiraled and planispiral), echinoid spines, sponges, crinoid ossicles, and thin shelled pelecypods.

The matrix makes up only about 20 percent of the rock. Rare rounded and angular quartz grains two millimeters in length are present.

Brachiopods are found in coral cavities, embedded in the coral surface or just lying on the upper surface. Both the corals and spongiomorphids exhibit a high density of borings. The rock is homogenous and is a 28

coral framestone. This facies is in the domination stage which is the

hi^h^st succession zone in the area. The corals and spongiomorphids

built a fairly rigid framework which may have resisted water erosion,

but was never tested because of the low water energy.

INTERREEF FACIES

This facies is composed of mound debris and therefore is not

homogeneous. The interreef occurrences are bedded or massive. Later­

ally this facies grades into biostromas or mounds. Vertically it is

bounded by mound facies or any other carbonate facies. The characteris­

tic feature is the whole or fragmented reefoid organisms within a light

to medium gray limestone matrix. No organic framework is constructed

and orientations of fossils are random. Gastropods and echinoids are

not as rare in this facies as in the others. Echinoids and gastropods

may have been more abundant in this facies because the open detritus

filled area was an attractive habitat due to abundance of debris,

detritus feeders, and open areas teeming with life. The fossil to

matrix ratio varies too much to be estimated, but the rock is matrix

supported. The insoluble residue varies from seven to 15 percent. The

silt is a minor component, tan colored and quartzose. Some quartz

grains are four millimeters in length and have a variety of forms such

as crystals, angular fragments, and rounded grains. This facies was in

the interreef areas between the mounds during and after mound growth.

The great amount of predation and minor erosion of mounds, and in situ organisms caused these interreef areas to cover a much larger area than

the mounds themselves. 29

CRINOID FLANKING FACIES

The occurrences are lens shaped, not bedded and are not sharply

defined. Six locations are known, these are a few meters thick and ten

or less meters wide. The rock is visually distinct and fairly homoge­

nous. The rock in hand sample is light gray with an abundance of

visible crinoid ossicles. Each locality shows some variation in the

fossil associates. At UNMSMM007-YA locality the associated remains

consist of red colored brachiopods, echinoid spines, thin shelled pelecypods and rare Trichites. The common position for this facies is as a flanking lens adjacent to a bioherm. Lithologies surrounding the

lenses vary for each locality. In one locality, a mound facies bounds one side and a bioclastic limestone bounds the lens on the other three sides. In another occurrence silty sponge bindstone and a pelecypod floatstone surrounds the crinoid lens.

The rock is a crinoid rudstone containing 70 percent organic detritus of which 86 percent is crinoid ossicles, and ten percent is thin pelecypods, while brachiopods and echinoid spines comprise the remaining four percent. Calcite veining is common and red and tan fine silt grains are dispersed throughout the matrix or in veinlets. The silt content is ten percent or less. The fossils are recrystallized and at least ten percent of the matrix is completely recrystallized and the rest is calcilutite. There are umbrellas of calcilutite under the pelecypod shells. The crinoid ossicles show incipient cleavage planes and are intergrown which is caused by microstylolization during the early compaction. Infillings of the brachiopod shells are lighter in color which is also due to compaction outside of the shells. 30

One interpretation of crinoid meadows or encrinites is that they

occur within a moderately high energy environment on the margins of reef

structures and because the skeletons readily disarticulate, vast quan-

tities of ossicles are produced (Ingels, 1963, p. 419). But the occur­

rences are lens shaped indicating less agitation (Lane, 1970).

GRYPHAEA FACIES

The Gryphaea facies is always bedded, homogenous, wide spread, and narrow. Surfically, the rock is a tan friable silty and shaley

limestone, finely recrystallized and containing black whole Gryphaea shells. These beds are commonly adjacent to terrigenous sediments and occur above or below the mound sequence. Organisms associated with this facies include brachiopods, Trichites, and other pelecypods.

Crinoids, echinoids, and corals are rare in these beds, as are gastro­ pods. The insoluble residue portion varies from 15 to 25 percent. The rock name for this facies is shaley Gryphaea floatstone. The fossil content is above 30 percent, and is predominately Gryphaea shells or fragments. The shells show little wear. The interpretation of environ­ ment for the beds is only little more than a guess. Gryphaea seemed to prefer shaley and silty limey sediments and excluded most other organ­ isms as common associates. The fine matrix and unworn shells indicate that the beds were laid down in quiet water conditions.

OTHER PELECYPOD BEDS

Bioclastic beds adjacent to the interreef facies consist of limey shales, shaley limestones, argillaceous limestones, limey argil­ lites, silty limestones, and all the lithologic variations in between.

The majority of beds are only about one meter thick and are filled with 31

fragments of pelecypods. A few of the beds have linear alignment of the

shell fragments. Shell fragments average one centimeter in length.

Some fragments are subangular, but most are angular. Brachiopods

represent approximately five to 15 percent of the biota and crinoids

can be an important contributor also. Other mound organisms, rarely

inhabit these beds.

A distinctive assemblage is present in a couple of localities.

These beds are a tan silty calcilutite containing whole brachiopods,

very large high spiraled gastropods, large pectens and other whole

thin shelled pelecypods.

Another unique bed is full of worm tubes or something that

resembles worm tubes. Worm tubes make up ten percent of the fossils; pelecypods comprise 70 percent; brachiopods comprise 15 percent, and

crinoid ossicles comprise two percent of the total fossils. Microgas­ tropods and small echinoid spines are rare elements. Sixty percent of the rock is matrix and is partially recrystallized and the inside of the worm .tubes is lined with pure sparry calcite. The rock is a shaley pelecypod floatstone.

The pelecypod beds generally have a microfauna containing gas­ tropods. The matrix to fossil ratio averages about one to one, but varies from bed to bed. The thin beds are frequently calcite veined and the matrix is partially recrystallized. Black micrite is present and makes up as much as 15 percent of the matrix. These beds are more frequent in the older strata which contain more terrigenous sediments.

CAVITY AND FISSURE FILLINGS

The majority of cavity and fissure fillings are found in the bindstone, interreef, and bafflestone facies. These fillings are on a 32

small scale and are usually a few inches in diameter. One bindstone

occurrence contains red—orown chert nodules in the fissure filling. The

fillings are distinctive because they are tan and are within blue-gray

limestones. The lithology is a silty fine calcilutite without fossils.

The insoluble portion of this limestone is 18 percent.

BLACK CALCILUTITE

The rock appears gray—black both on the weathered surface and on

fresh exposure. Calcite and silt veins are common and the rock has

undergone some microstylolization. The texture is a mottled ghosty

unsorted calcilutite due to recrystallization or due perhaps to the

agglutination of micromicrite. Megafossils are very rare and are always

high spiraled gastropods.

LITHOCLASTIC BRECCIA

The clasts are unsorted and six inches or less in diameter averaging one to two inches in diameter. The bed in one locality is continuous for at least 31.5 meters and is 0.9 meters wide. The clasts are homogeneous and contain no fossils. The matrix is a tan silty cal­ cilutite and the clasts are a dark grey calcilutite. The clasts are all angular and randomly oriented. Wilson (1975) said that the clasts in such a breccia are partly or totally lithified and torn from other beds by collapse or wave action and slumped or are carried by currents.

Commonly in many mounds, these clasts are lithoclastic in other mounds, as they are in the Cinnabar-Dunlap Canyon area. Erosion is not very apparent and the whole area enjoyed relatively quiet conditions; so the processes involved in the formation of these beds are a mystery, as in the breccias Wilson studied. SHALE AND ARGILLITE BEDS

The shales and argillites consist of calcite, quartz, white mica, and koalinite according to X-ray analysis (Nielsen, 1964). The shales have five to ten percent calcite according to insoluble residue studies. The argillites can have up to 20 percent calcite or with fossils up to 35 percent calcite.

The shales can be found in a variety of colors including red, purple and green, but the commonest colors are gray or brown. The thickness varies from paper thin to about 0.7 centimeters, and the thicknesses of the occurrences vary from a few centimeters to over 15 meters thick. If the shales contain any fossils, they almost always are pelecypods.

The tan to red argillite beds in the lower Luning vary in thick­ ness, yet the thickest bed is only 2.5 meters. The argillites contain more fossils than do the shales, including a variety of pelecypods and minor amounts of crinoid ossicles. PALEOAUTECOLOGY

The ecology of the individual groups is a building block in the

reconstruction of ancient environments. The generic level is the small

est taxon which can be adequately studied in the Cinnabar and Dunlap

Canyons. Benthonic organisms are good environmental indicators. The

rooted bottom dwellers are the best indicators because of their strict

associations with the environment. In this study, corals, spongiomor— phids, and sponges are the best indicators followed by crinoids, echinoids, brachiopods and some pelecypods. Microfaunas are excellent

for studying the substrate characteristics.

The biological factors include food supply, symbiotic relation­ ships, competition, predation, dispersal and morphology. The physical factors are important to the environment, but are not easily inter­ preted.

To a large degree, recrystallization interferes with the inter­ pretation of the paleoautecology in Dunlap and Cinnabar Canyons.

PORIFERA

The calcareous sponges of the Triassic were opportunistic, but could not compete well with corals and other framebuilders. During the interval after the rugosans' disappearance and before the scleratinian dominance, the calcisponges had a major role in the building of the reefoid framework. Thalamid sponges were the dominate framebuilder sponge in the Middle Triassic and phaerotronid calcareous sponges had a similar dominance in the later Triassic (Fischer, 1969) . Both thalamid and phaerotrone sponges are important framebuilders in the

St. Cassian (Karnian) reefs of the Italian South Alps. 35

Cylindrical and laminar-tabular types are present, all of which

are segmented, chambered, and vesicular. Ott (1967) states that this

particular sponge morphology is a reef adaptation and that the segments

are rhythms of growth which permit flexibility for waving in moderate

currents.

Sponges gather their food by filtering nutrients that come

through their pores. Recent sponges depend on a supply of land derived

nutrients. Lower Luning sponges probably derived some of their nutri­

ents from the clastic influx into the area.

The cylindrical genus, Polytholsia, had a rigid skeleton which

enabled it to grow up to 40 centimeters tall (Seilacher, 1962, p. 50).

This rigid skeleton supported brachiopods, corals, pelecypods, and

possibly other organisms. Even in death, the skeleton remained rigid

forming a firm base for other organisms. Sheets of encrusting sponges

grew to be 6.1 meters long and up to two centimeters wide in some

localities. These sheets had a great amount of surface area which

helped to stabilize and bind the silty lime mud. Both types of sponges

acted as colonizers by providing a firm base for further growth of the

bioherm. It is possible that sediment baffling also took place in the

sponge communities.

The common associates of these sphinctozoans were Trichites,

spongiomorphids, and thin shelled pelecypods, but not corals. Competi­

tion with the corals appears to have been keen. The higher the succes­

sion stage reached by the mounds, the lesser the role played by the

sponges. The corals offered little competition to the sponges in the

colonizing stage. Crowding and high density of sponges is only found where corals are rare. Recent corals have efficient mechanisms to 36

protect their immediate environs from invasion and the same was probably

true with these earlier corals.

Sponges are found in most of the fossil communities, but they

seem to prefer silty sediments over the shaley sediments. No fragments

or spicules of the sphinctozoans have been found in the area testifying

to their durability as a whole unit.

Rare specimens of both genera, Ascosymplegma and Polytholsia,

found by Seilacher (1962), exhibit tiny scratches on the outer surface.

He also found similar borings on another species, Polytholsia polystoma,

in Nevada. An acrothoraica (a cirriped) was probably responsible for

these shallow 3 millimeter long somewhat regular razings (Seilacher,

1962).

The laminar-tabular sponges often form a sort layer cake effect by being stacked one upon the other with a small vertical spacing of

sediments between them. The cylindrical sponges appear intertwined and crowded in areas where they are dominant, but in life they were upright and not really very crowded.

The sponge genera can be found together or separated, though one species will dominate the other. The dominant sponge in the early part of the colonization stage is the laminar sponge.

Sphinctozoans are found in depths of four to 18 meters in the

European Triassic (Ott, 1967) . M.W. De Laubenfels indicated that the calcisponges were found in clear euhaline water conditions in a depth less than 100 meters, but not less than 30 meters (1957, p. 771).

Because of the strong competition with corals, sponges and spongiomor- phids occupied ecologic niches undesirable to corals in quiet oxyge­ nated muddy lime bottoms (Ohlen, 1964). 37

SCLEROSPONGES

Spongiomorphids (stromatoporoid-like sponge made up of horizontal laminae and vertical pillar structures)

Mesozoic spongiomorphids were important as framebuilders or binders. These are related to the modem sclerosponges of Jamaica.

The modem types grow only in deeper water (below 70 meters) and in shallower waters they are only found in shaded areas (Hartman and

Goreau, 1970). Below 70 meters they can be the dominant framebuilder and are associated with brachiopods (Jackson, Goreau, Hartman, 1971, p.

623) .

Spongiomorphids became more dominant later in the Upper Triassic.

Corals and spongiomorphids shared dominance in the Norian and Rheatian stages. This dominance may have been, in part, because the scleratin- ians created shade by their growth forms which may have permitted invasion of brachiopods and sclerosponges (Jackson, Goreau, Hartman,

1971, p. 625).

In the study area associates included corals, sponges, brachio­ pods, and pelecypods. Both Spongiomorpha and Stromatomorpha are found throughout the mounds in various stages of succession. Laminar forms were present in the colonization and diversification stages. Branching forms were found in the diversification stage. Encrusting forms prob­ ably were important but because of recrystallization, only a few examples have been found. The bulbous or branching spongiomorphids were able to grow larger.

Of all of the preserved biota, the spongiomorphids were preyed upon the most. Surficial boring was evident and in all three dimensions of the animal in many cases. The animal grew faster than the predator 38

could eat because in many instances the boring is surrounded completely

ky the skeleton Ox. the spongiomorphid. Predation was the most severe in

the laminar forms, but amounts of predation upon the fossil community

could not be estimated because of the recrystallization. Possible

recent borers which would have been important in the past are gastro­

pods, pelecypods, algae, foraminifera, and arthropods.

The branching type of spongiomorphid was the only form that was

not very common. Spongiomorphids shared the dominance as framebuilders

in several bioherms in lower stages of succession. In the dominant

stage, they only played a supportive role in framebuilding. They were

probably important as binders of the muddy lime sediments. Nearly all

the carbonate facies contain some amount of spongiomorphid fragments,

part of this is caused by the large amount of predation, though they

probably also grew in many environments. These generalized animals had

an ecophenotypic response to their environment and they lived in a

variety of different habitats.

Mud is associated with some of the worldwide occurrences, prob­

ably because corals competed better in less muddy conditions, and maybe because as Braithewaite (1973, p. 1110) said the spongiomorphs were

tolerant of mud because they avoided strong light by growing in a muddy environment. This would allow them to invade shallower depths because of the lessened light. The Triassic spongiomorphs were not found in deeper waters, where you would expect to find them if light was as great a factor as it is to sclerosponges. I believe the spongiomorphids lost their tolerance of light throughout the ages as does Hartman and Goreau,

(1970). In the late Jurassic they were associated with euhaline organ­ isms, warm water, and are associated with more saline environments 39

(Wilson, 1975, p. 263). The Paleozoic forms which are structurally dif­

ferent were found in clear, warm, shallow water in reefs. The Paleozoic

laminar forms were found in the less pure limestones and bulbous forms

were found in the purer limestones. This latter preference is found

in the area of this study, as well. Ohlen's statement in the sponge

discussion adds oxygenated water to the physical requirements of spongi-

omorphs.

CORALS

Corals are the best environmental indicators of the rooted

bottom dwellers. Hermatypic corals indicate shallow, stenohaline, warm,

well lighted clear water. It is not known whether these corals are

actually hermatypic because the symbiotic algae do not preserve. Coral

morphology changes in response to the environment. Caution must be

used in employing interpretations of the morphology, because the mor­

phologic response may be family or genus related. Generally, compari­

sons must be made with related genera or species, though some generali­

ties can be ascertained from similarity in morphologies. An assumption

is made that the morphology is water energy dependent.

Corals are easily recrystallized and in localities of great coral densities, the recrystallization is so complete the corals are not recognizable. Predation is evident in the corals of the study area.

These borings are the same shape and size as the spongiomorphid borings, and in all probability are made by the same.organism or organisms.

Modern destructive agents include fish, echinoderms, gastropods, deca­ pods, algae, worms, sponges, pelecypods, foraminifers and the starfish,

"Crown of Thorns." Coral predation is important in modem reefs and seems to be a factor in these mounds because the corals shape and growth 40

patterns are altered by predation and the coral detritus may be a major

contributor to the sediments. Borings in Holocene corals closely

resemble the Triassic coral borings in the study area (fig. 5). As seen

in spongiomorphids, the coral populations also grew faster than their

predators could eat them.

There are ten species of corals in the Cinnabar and Dunlap Can­

yons. The major mound framebuilders include Thecosmilia, Pamiroseris,

Elysastraea, Palaestraea, and Astrocoenia. Montlivaltia is the common

solitary coral in the mounds.

SUPERFAMILY THAMNASTERIODIDEA Alloiteau, 1952

"Thamnasteria"

Recently this genus was placed into two different families, but the ecologic preferences and morphologic forms seem to be the same. ft "Thamnasteria" is usually found as dish shaped or slightly basket-shaped thin sheets. These forms occur in several Triassic and Jurassic bio- herms near the base of the buildup. "Thamnasteria" in the late Jurassic was found below 30 meters in windward dark waters and also had a sheety form. In the Triassic reef knolls of Hohe Go’ll, "Thamnasteria" is also present. The middle phase of the Steinplatte reef growth included vast amounts of "Thamnasteria." Here it was not found toward the biohermal base, but in the core. An idealized Upper Jurassic patch reef shows

"Thamnasteria" above the sponges and below the Thecosmilia (Wilson,

1975) .

In the Cinnabar and Dunlap Canyons the sheets are 0.5 to one centimeter wide and up to 30 cm. in diameter. The coral to matrix ratio was about one to three. Three to five centimeters of matrix separated the corals vertically. "Thamnasteria" (Pamiroseris) was the first coral 41

A. Borings in coral from the Lower Luning Formation in Dunlap Canyon. Stippled area is coral, striped area is matrix, IX.

B Borings in Bahaman coral, Holocene. From Zankl and Schroeder (1975, p. 531, fig. 6a).

Figure 5 Comparison of Triassic coral borings (A) and Holocene coral borings (B). 42

to invade the pioneering stage. These corals seem to be tolerant of

poor light and muddy sediments, in order to be at the base of the

mounds. The morphologic form of the coral heads was perfect for maximum

coverage of the sediments and for maximum utilization of light and water

currents. They were associated with other colonial corals, solitary

corals, spongiomorphids, brachiopods, pelecypods primarily Trichites,

and sponges.

In the Cinnabar Canyon mounds, Pamiroseris is found above the

sponges and principally below the Thecosmilia bed. This occurrence is

the same as in the European late Triassic mounds. Individual Pamiro­

seris corallas are thicker higher in the mounds. In the domination

stage Pamiroseris is not common.

Thecosmilia

Thecosmilia is a large fasciculate dendroid coral which was a

common bafflestone former during the Upper Triassic. Thecosmilia is so

dominant in the bafflestone facies that very few animals associate with

it. Commonly it occurs in micrite. In the Dolomite Alps as in the

lower Luning Formation the colonies are on the order of a meter or so

in diameter. The colonies are bedded as biostromes commonly and are

found in backreefs and forereefs (Leonardi, 1967). In the Hohe Goll

and Steinplatte, Thecosmilia is present in the more protected backreef

and in the quiet basinal beds (Zankl, 1969, 1972). In the deeper waters of the Rotelward bioherm Thecosmilia was the main framebuilder. At

Hohe g 8 h Thecosmilia was ten meters high.

In Cinnabar and Dunlap Canyons, Thecosmilia occurs in beds 1.3 meters high more or less. The fine calcilutite matrix is cream colored 43

and distinct. Thecosmilia is almost always found in beds. The heads

reach 1.3 meters in diameter. Commonly branches are broken up into two

to five centimeter lengths. They exhibit slightly different morphologic

forms in different localities, but they are almost always crowded.

Thecosmilia beds are found near the bottom of the bioherms and may be

the colonization stage. Their few associates include brachio-

pods, small pelecypods, a few spongiomorphid fragments and echinoid

spines. The brachiopods and pelecypods may have lived between the

branches of the coral, but I doubt if any other biota coexisted with

the Thecosmilia heads.

Other Colonial Corals

Elysastraea and Astrocoenia were the dominant corals in the

domination stage; there exhibiting a bulbous form. Bulbous forms are

usually found in quiet areas below wave base. Very rarely these corals

were found as stocks. In the other ecologic stages these and other

subordinate corals were found in laminar or irregular shapes. Within

any particular bioherm the corals are about the same thickness. From

locality to locality the thickness of the corals varies from 0.5 centi­

meters to about 20 centimeters, with an average of about five to 7.5

centimeters. The morphology of these corals and other mound organisms

will be discussed in more detail later in the paper.

Montlivaltia

Montlivaltia marmorea (Freeh, 1890) is a large solitary coral

found in Europe and North America associated with bioherms. All the mound facies and the interreef facies have some random occurrences of this coral. In the less developed bioherms the coralla are very short. 44

with a large diameter. In the boundstone bioherms, the corallas are as

much as 13 centimeters in length. Montlivaltia norica (Freeh, 1890) is

also present in the bioherms. This species is small and is rare in all

mound and interreef facies.

BRACHIOPODS

Triassic brachiopods are not now well understood in their

reefoid occurrences. Ager (1965, p. 152) doubted their existence in

coral reefs. Elliott (1950) suggested that they were not coexisting

with corals because the corals ate them. Brachiopods exist in modern

reefs. The deep-water ahermatypic corals characterize an environment

in which living brachiopods may be abundant (Moore, 1956, p. 213). He

states that the brachiopods may have been rare on true reefs since the

Paleozoic because the temperature and depth are unsuitable or that

predation by fishes, etc., is too great (Moore, 1956).

Brachiopods are found in a modern reefoid occurrence in Jamaica.

In the 70 meter and deeper waters, dominated by sclerosponges, small

brachiopods are common. Above this depth brachiopods can be found in

the shade of coral colonies. Dagys (1965) mentions several brachiopod

occurrences in Triassic bioherms within the Soviet Union. In the

Triassic system of Europe, they occur near reefs and in the algal build­ ups. Wilson (1975) mentions some terebratulid brachiopods in Rheatian bioherms. Ohlen (1959) found brachiopods in the deeper banks of the

Steinplatte and states that they might have lived on the bioherms after these ceased to grow. Because the Dunlap and Cinnabar Mounds are in deeper quiet waters, their association with brachiopods is probably not that unusual. I believe the brachiopods were mainly limited in their habitats by water energy and secondly by depth. 45

Brachiopods have a narrow environmental tolerance and are

restricted to well oxygenated stenohaline water of low turbidity. They prefer subtidal areas and are almost never found in shallow strongly agitated waters. In depths down to 5500 meters in polar to tropical waters, they are known to thrive. Most brachiopods attach to hard sub­ strates when available, however in muddy environments they may attach to shell material or algae, some are even able to root themselves in soft sediments. All brachiopods are sessile benthonic, epifaunal, gregarious, and are major contributors to sediments. Living brachio­ pods eat diatoms and dinoflagellates by collecting them in suspension.

Their staple food supply has always been primary producers. In turn, fish and carnivorous gastropods eat brachiopods and in the Mesozoic fish and reptiles feasted on them. Modern associates in the Catalina Island area are primarily annelids, mollusks, and echinoderms.

The Cinnabar and Dunlap Canyon brachiopods do exhibit an odd apparent preservation of fossil coloration. Brick-red color brachiopods are found in the crinoidal limestone and in the mound facies. All the species can be colored, but the spirifer species exhibit the most color­ ation. Looking at the shell in cross section the color becomes lighter in the deeper layers of the shell. Other biota of the area do not show any coloration. A living example of a red colored brachiopod is found off of Catalina Island. This brachiopod, Laqueus californicus, is pink colored in depths down to 300 feet and below this depth is white. If the coloration is original, these Triassic brachiopods lived in rela­ tively shallow waters (Williams, 1956). The other explanation is that the brachiopods have a slightly different shell chemistry and structure and if iron is added to the sediments, iron might possibly differentially 46

stain the shells.

In the mound facies the spirifers are the most abundant. In the

pelecypod facies the terebratulids are the most common. Brachiopods are

found in all the facies but are never common. The spirifers may attach

to corals for spirifers are found embedded in corals and on the upper

coral surfaces. In most species such living attachment no longer holds

when the animal dies.

MOLLUSCA

Bivalvia

Oysters

The earliest appearance of oysters is in the early Karnian. In

the Upper Triassic, there are three genera of oysters, two of which are

found in the Dunlap and Cinnabar Canyons area.

Gryphaea

Gryphaea has a circumpolar distribution and originated in the

Arctic sea. The Nevadan occurrence is only feasible because of a possible oceanic passage from the north into this area. Their rapid

success was due to their ability to live on soft sediments.

Gryphaea is associated with ammonites, corals, echinoids, and euhaline animals. They lived below the strong wave action and tidal currents and far enough from shore to be outside the influx of fresh or brackish waters. Gryphaea could live in warm, cold, deep or shallow water. Commonly they are found in clays, marls, chalks, glaconitic marls and soft, water logged, oozes with fragments of shells. The sediments commonly have iron sulfides (dark colored) or marcarsite and pellets. In the life position, the large left valve is floating in the 47

muddy bottom and the valve commissure is horizontal. Its weight is

thus equal to the weight of the mud displaced. The shape of the shell

allows for balance and distribution of load. Vigorous self cleansing is

necessary in such an existence.

In the Cinnabar and Dunlap Canyons, they are usually found in

life position. One facies is almost totally dominated by them. They

occur with small pelecypods, gastropods, Trichites, and terebratulids.

The fine mud of the area would have been excellent for animals not need­

ing a hard substrate for support. Gryphaea was one of the few animals

able to exploit this muddier habitat. Gryphaea in turn was restricted

to.this habitat. This restriction may have been due to stiff competi­

tion for the other habitats.

Lopha

Lopha is restricted to Mesogean and Pacific Triassic realms.

They are associated with Gryphaea in the passageway toward the north.

This is only known to have happened in the Nevada Luning Formation where the Arctic and Mesogean faunas intermingled.

Crinoids, corals, brachiopods and sponges are their common asso­ ciates. They lived in warm euhaline waters. In the Cinnabar and Dunlap

Canyons, they are common in the debris piles that formed the base for the mounds. These debris piles were dominated by Lopha and supported by other pelecypods and uncommonly brachiopods. The pile consists of shells with only a small amount of matrix. Lopha was not well preserved and only fragments are usually found. Presumably many of the facies contained Lopha in small numbers. Pinnidae

Pinnidae are found from the Carboniferous to Recent. The

anterior end of the shells is buried in soft sediment and the hinge margin is more or less vertical. Exposed is the wide posterior end of

the shell. The byssus is anchored to underlying stones or other solid objects. Commonly the anterior end of the shell is worn off and sealed off by thin partitions at the same time. The anterior adductor migrates to the posterior position. They are vertical burrowers and semi- infaunal. Pinnidae predominate in some shallow water areas of high current and wave activity in soft sand, silt or clay.

PINNA

Living forms are found in tropical or subtropical seas. The fossil forms are cosmopolitan. Pinna is common in Jurassic bioherms.

In the lower Luning it is rare and usually only found as fragments in pelecypod beds.

TRICHITES

Trichites is common in Jurassic reefs and other habitats.

Trichites is common in the sponge-Trichites assemblage and in Gryphaea and other pelecypod facies and in the biohermal pioneering and coloniza­ tion and diversification stage, and a few are found in the coral frame- stone facies. Thick shells are thought to imply rough water. In several of the Trichites localities the shells were up to five centi­ meters thick. Thickness varied from locality to locality, and where they were more dominate the shells were also likely to be thicker.

None of the facies associated with them experienced rough water.

Stanley (1970) states that the great thickness serves to stabilize the shell by the increased whole-animal density, which is characteristic of

shallow burrowers. Trichites was not found in the growth position, but

instead with the valves parallel to the bedding surface. The valves

though are usually found together and shut, so in all likelihood did not

undergo much transport.

CEPHALOPODS

Ammonoids were nektonic swimmers who rarely lived in very shal­

low conditions or in coral reefs. When ammonoids are found in fossil

reefs, the conclusion is that they floated in alive or more frequently

after death. They inhabit a wide range of niches. In the Cinnabar and

Dunlap Canyons ammonites have been found very rarely, yet from the few

fragments six genera have been identified. Carnites and Klamathites were found in the shale beds by Muller (1936) . These and two other

genera belong to the Carnitidae family.

Modern cephalopods are carnivorous and it is presumed that their ancestors were also. Stomach contents of a Jurassic ammonite were pre­ served. Found inside were benthonic foraminifers, ostracods, small ammonoids, and crinoids, implying that some ammonoids depended on the bottom organisms for food (Lehmann and Wetscat, 1973). Fish and marine reptiles ate cephalopods.

A genus of Belemnites, Atracites, is found in the study area.

In the study area Atracites is very rare, but when found they are always in groups. Belemnites are thought to be nektonic squidlike cephalopods that probably fed on small fish and crustaceans.

One lower jaw of a cephalopod, referred to as Conchorhynchus, was found in the pelecypod facies. This genus is thought to belong to 50

Table I

Bivalve Living Habits and Trophic Levels in Cinnabar and Dunlap Canyons

SUSPENSION FEEDERS

EPIFAUNAL

Byssate free-swinging forms- Pteria

Byssate, closely attached, exposed forms- Mytilus

Byssate fissure dwellers- Chlamys (some), Lima, Mysidioptera

Cemented forms- Lopha, Gryphaea, Placunopsis, Megalodonts

Free living epifauna swimmers- Entolium

non swimmers- Cardita (some)

SEMI-INFAUNAL- Pinna, Trichites

DEPOSIT FEEDERS (some)

INFAUNAL- Pholadomya, Cardita, Trigonids, Myophoria 51 the family Nautilida. They have been found in deep and shallow water sediments.

Gastropods

Not much is known about Triassic gastropod paleoecology. Gas­ tropods are scavengers and carnivores. As scavengers they are active in bioturbation.

The study area contains rare, large, 15 centimeter tall, high spired gastropods in a tan silty calcilutite. Medium size, high spired gastropods are uncommon in the interreef facies and rare in the bind- stone facies. High and low spired small gastropods and microgastropods are found in most of the facies. The most common microgastropods are high spired. One species of discoidal gastropod, Brochidum spinosum

Korner, 1937 is seen in the mound and interreef facies. Rare plani- spiral microgastropods are found inside coral borings, sponge pores and other cavities.

In all the gastropods prefer the siltier and muddier sediments in the Cinnabar and Dunlap Canyons. Microgastropods are very active in bioturbation and eat small detritus. Immature forms have not yet been differentiated from the mature microscopic forms in the lower Luning facies.

ECHINODERMS

Echinoids

Cidaroids

Cidaroids are ancestral to all other surviving echinoids. They first appear in the Late Triassic and have their peak of development during the Mesozoic. Today they are common in the Indian and Pacific 52

Oceans where they can be found in tidepools or in depths down to 4000 meters. The Triassic forms parallel that of living forms sufficiently

to imply that their ecology would be very similar.

Echinoids disintegrate rapidly after death and only the primary

and secondary spines are common fossils. Each individual echinoid has many spines. These spines are large, light and are easily transported.

The strong crystalline structure of the spines allows them to be trans­ ported without any destruction.

Echinoids are herbivores and predators. As predators they feed on mollusks, annelids, polyzoans, foraminifers, and sponges. They are efficient predators because of their strong teeth to crush hard parts.

Cidaroids have round bodies which would indicate they preferred hard substrates and reefs. Long slender spines support echinoids in the mud. A few of these long spines were found in the Cinnabar and Dunlap

Canyons. Most echinoids in the study area probably had club shaped

spines. Apparently, they moved very slowly and preferred shallow euhaline water. They probably did not hide during the day as some other echinoids do. The modern echinoids can live at a minimum temperature of

-28°C degrees. Commonly echinoids have commensals and parasites, but none were found with the spines in the study area. Few predators ate

them because of their strong skeleton and spines.

They are found in many of the mound habitats, this is because

the club shaped spines are easily transported. So it is most likely,

that they did not live in all the facies. Primarily, they are found in

the mound and interreef facies, where they probably lived. It is diffi­

cult to estimate their abundance because the spines are small compared

to the other megafaunal elements and they are also widely dispersed. 53

Crinoids

In the Triassic, there were two forms of crinoid stems: the round Encrinus and the pentagonal Isocrinus and Pentacrinus. Crinoids generally need moderate currents, are gregarious and form flanking beds on reefs. In the Steinplatte, crinoids flanked biohermal masses prior to reef development. This environment was moderately agitated, had a firm substratum and very little debris was shed from areas of higher relief.

Where there was an abundance of detritus, the crinoids were not as common

(Ohlen, 1959, p. 72). If crinoids are living where the sedimentation is slow and the currents weak, a lens shaped accumulation will result (Lane,

1970, p. 1440). Crinoid ossicles are transported readily because the ossicles have a honeycomb microstructure that lowers their density and even gentle currents are capable of moving a large ossicle (Schwarzacher,

1963). Crinoids fed on small organic detritus. One predator of the crinoids may have been sharks because living primitive sharks (hetero- donts) feed on starfish and sea urchins (Lane, 1970, p. 1442).

Crinoids are ubiquitous in the study area. The ossicles are found in every limey environment. The main concentration and presumed life habitat is in the crinoid mound flanking facies. The rate of sedi­ mentation must have been slow because the stems had time to disarticulate into individual ossicles. Associated with this facies are brachiopods, pelecypods, corals, echinoids and a few branching corals. It is uncer­ tain if these animals lived in the crinoids habitat or not.

VERTEBRATES

Ichthyosaur and perhaps other reptile bones are found in all facies. As many as 20 different sites yielded vertebrate bones. Bones 54

are even found between corals in the bindstone. More commonly the bones were found in the shaley or more argillaceous beds stratigraphically below the bioherms. Most of the remains were of large individuals, but

some smaller bones also have been found.

This occurrence of the large form of the Ichthyosaur in shallow waters and near bioherms is very unusual and may have important implica­ tions . They usually inhabit moderate depths and they are carnivores feeding on ammonoids, squids and nektonic fauna. 55

Table II

Distribution and Abundance of Organisms in Dunlap and Cinnabar Canyons

Organisms 1 2 3 4 5 6

Porifera r c uc UC Corals uc a a a uc Spongiomo rphi ds r a r a r r Pelecypods Epifaunal Byssate r r r r uc Free Living r r r r uc Cemented uc uc a c Semi-infaunal r uc uc r uc Infaunal r r r Brachiopods Spirifers uc UC r uc r r Terebratulids uc uc r uc uc UC Gastropods Low Spiral uc r r uc High Spiral uc r r uc Discoidal uc r r Microgastropod r r r r r r Crinoids a uc r UC uc uc Echinoids uc c uc r r Cephalopods r r r Vertebrates r r r

1- Crinoid facies 2- Interreef facies 3- Bafflestone facies 4- Framestone facies and Bindstone facies 5- Gryphaea facies 6- Other pelecypod facies r- rare-less than 5 percent uc- uncommon-5 percent or over c- common-10 percent or over a- abundant-20 percent or over PHYSICAL PALEOSYNECOLOGY

WATER DEPTH

The entire Luning sequence is considered to have been deposited

in shallow water. The lower part of the Luning Formation was deposited

near both the eastern and southern shorelines. The shoreline probably

didn't shift to the east where the Shoshone Mountains are now until the

very end of the Karnian stage. I believe the water was relatively

shallow, about 100 meters or less deep in the study area, but below

wave base.

Corals, a traditional depth indicator, cannot be safely used

because they were probably not connected with symbiotic algae which

needs good light. Many other taxa present do show a preference or need

for shallow water; these include calcisponges, spongiomorphids, pinnidae

and brachiopods. None of these are ordinarily found below 100 meters,

except brachiopods.

The most important indicator of very shallow water is algae.

It is the only organism that is strictly depth dependent. The absence

of algae would indicate the mounds were below the photic zone which is

100 meters in the tropics.

Criteria for recognition of shallow warm water (according to

Heckel, 1974, p. 130) includes: (1) great abundance and diversity,

(2) association with large amounts of skeletal carbonate including mud,

(3) a particular biotic assemblage including stenohaline biota and

(4) agitation.

(1) Diversity at higher taxanomic levels is evident in most

Triassic buildups, but they lack diversity at the species level. Stein- platte buildup, postulated to have been in 30 meters of water, has only

56 The number of taxa found in the study area is 70, a very low

number of taxa for such complex ecosystems as are involved in and around

bioherms. There is an abundance of remains in these mounds. Even if the

sedimentation rate is very low, the remains would still be considered

abundant.

(2) The mounds contain large amounts of skeletal carbonate and

some limey mud.

(3) The assemblage is generally shallow water and many organisms are stenohaline.

(4) Agitation was poor. Moderate agitation occurred in a few places, but most of the area was in quiet water.

The deep cold water buildups near Norway contain 200 species,

100 of which were capable of forming hard skeletal remains. The build­ ups are 60 meters thick, but the organisms are not crowded into an organic framework. The colonial corals grow up to 60 centimeters in diameter. They have a rigid sediment binding framework requiring cur­ rents (Teichert, 1958, p. 1054) . Depths vary from 180 meters to 850 meters (Milliman, 1967, p. 237). Shallower cold water buildups have red algae and a wide variety of different taxa but lack the numbers of species.

Heckel (1974, p. 132) said the North American Triassic bioherms may be on continental slopes created by the mountain building. Teichert

(1958) said that the lower Upper Triassic coral banks and patches can be paleoclimato Logically compared with modern coral banks of the higher latitudes. 58

The Cinnabar and Dunlap Canyons buildups have similarities to all three types of coral buildups. Other bioherms have a similar lack of sharpness of definition. Jurassic carbonate buildups in northwestern

Europe do not contain calcareous algae/ but some contain sporadic red algae. In this case latitudinal control may be the answer, but it might also be that calcareous algae needs very shallow water to support good growth (Hallam, 1975, p. 391).

Low species diversity does not necessarily imply cold or deep water. The lack of symbiotic algae or proper nutrients or some other geographic, geologic, or biologic factor could limit the diversity or growth. Many of the faunal elements need or prefer warm shallow water.

The lack of algae may indicate a restriction to a shallower depth than algae now requires (Hallam, 1975). Perhaps the muddy environment caused the aphotic zone to be nearer to the surface. The probability exists that the mounds are of deeper water origin, below the photic zone. When

I compare the European and North American bioherms, the similarities are striking. Therefore I agree with the depth restrictions of the mega- faunal elements, proposed by the European Triassic workers. These restrictions imply that the mounds are below wave base and above 100 meters.

LIGHT CONDITIONS

Light conditions will remain a mystery unless these mound corals are proven to be hermatypic and contain the essential symbiotic algae.

RADIATION

It is postulated that the whole world climate was warmer in the

Mesozoic because of increased solar radiation. Evidence is based on 59

floras, coal beds, coral bioherms, lack of glacial evidence, and other

data.

TEMPERATURE OF THE WATER

The megafauna preferred warmer waters, but there is no direct

proof of the water temperature.

SHAPE OF THE WATER BODY AND GEOMORPHOLOGY OF THE LAND SURFACE AND SEA FLOOR

Several close sediment sources such as volcanic activity and mountains were near to the shoreline or within the embayment. The sea

floor was irregular in the embayment, though there is no evidence for

irregularities in the study area. The shape of the water body is unknown.

WATER MOVEMENT

Moderate currents were important in some facies, but gentle cur­ rents were more prevalent over the area. There was no evidence for a great amount of erosion of the mounds or other strata. The breccia beds, being very rare, contribute only minorly to the general sedimento- logic regimen. Currents were strong enough to supply nutrients and move sediments away from the crinoids, spongiomorphids, corals, and sphinc- tozoans. Water movement was strong enough to orient pelecypod fragments into horizontal layers. According to the Hjulstrom size velocity curves, it would take a .2 centimeter per second current to move silt size particles. The skeletal fragments are the only larger particles in the study area and since their shapes vary, a movement velocity would be difficult to estimate. 60

BOTTOM SEDIMENTALOGICAL CONDITIONS AND SEDIMENTATION RATE?

The bottom was probably well oxygenated, shown by the oxygen

loving benthonic fauna. Some of the bottom may have been slightly reduc­

ing or reducing just below the surface because of the presence of a

strong H2S smell and pyrites. The bottom may have undergone slight com­

paction of the carbonate sediments, trapping water with the entombed

organic matter, resulting in reducing conditions (Wilson, 1975).

Recent studies of reefs show a remarkable rapid lithification

taking only thousands of years. But this lithification is subaerial and

submerged reefs are thought to lithify more slowly. Cementation proc­

esses are not well understood even in recent buildups, but are in the process of intense investigation. Because these mounds lack any good binding organism, rapid lithification and cementation would provide the necessary framework of support for the organisms. A thorough diagenetic

study of these mounds is needed to address these problems.

Slow sedimentation is evident in several areas, particularly in

the limey argillites and the silty pelecypod limestones. In these beds

Ichthyosaur bones were found with epizoans attached. The sedimentation rate was slow enough to allow disarticulation of the bones and growth of other organisms. The mounds were not suddenly inundated with shaley sediments, but rather gradually stopped growing and the interreef debris and pelecypod fragments accumulated on the mounds. The beds grew more shaley upward till they contained only shale or argillite. The great densities of fossil remains in some beds also would indicate slow sedi­ mentation. There were times of minor erosion or no sedimentation, as the beds are often sharply truncated. The limiting factor is that sedimenta­ tion must be rapid enough to seal the remains from deterioration. The 61 main variable in this area was the changing amounts of terrigenous influx and their effect on carbonate production. MOUND SYNECOLOGY

The Cinnabar Canyon and Dunlap Canyon mounds did not have the

topographic expression usually associated with carbonate buildups. The

mounds topographic relief could not have exceeded 17 meters. Outcrops

indicate that the mounds were elongated lenses; indeed some were so

flattened that they are biostromes technically. The average mound was

only three meters high, seven or 10 meters in length, and an unknown

width (fig. 6).

The stratigraphic interval containing bioherms does not exceed

70 m. in any area. Both the upper and lower plates of the thrust fault

have distinct intervals of bioherm development. The bioherm zone occurs

at the top of the lower Luning section on the lower plate. The position

of this zone appears to be lower in the lower Luning section of the

upper plate. The time difference between these two intervals is probably

not significant; since the ecologic succession, dominant species, and associated species are the same.

The number of coral units within a stratigraphic interval does not exceed five. Shales are always intercalated with the bioherm units.

Figure (7) shows the distribution and location of reefoid beds. Inter­ reef areas share the same stratum. Volumetrically the interreef facies dwarfs the mounds and biostromes combined.

These mounds resemble the Type II Knoll Reef Ramp described by

Wilson (1975). As in the type II bioherms, vertical zonation is common and massive forms dominate the higher levels. Type II and lower Luning bioherms are both produced by organic productivity, binding, trapping, and encrusting, and by lack of removal as by in situ frame construction

62 63

* crinoid ~ r coral (branching) *' oyster

"» Trichites & = £ c s a ^ sponge (laminar) S spongiomorphid

iv corals pelecypod *- calcilutite

spongiomorphids A sponge shale (branching)

Figure 6. Mound diagrams showing biological elements of the mounds and changes upward of biological succession. Mound locations Tir Pliocene Mammoth rhyodacite Canyons Tes Miocene Esmeralda Formation Lithologic contacts To Miocene andesite breccia

ftlm Sc. le 1.27cm= 865m Luning Formation- limestone and shale

fcla Luning Formation- argillite and conglomerate

h \ Lower member of Luning Formation

Figure 7. General geologic map of Cinnabar and Dunlap Canyons showing locations of biohermal mounds.

Oi 65

by organisms. In both interreef materials are quantitatively impres­

sive. Type II mounds have mud in the reef core because protection is

afforded by the framebuilders or because there is an internal trapping

mechanism (Wilson, 1975) . The Cinnabar and Dunlap Canyons mounds contain

great amounts of calcilutite which may have accumulated in much the same

way. An example of a type II late Triassic reef is the Thecosmilia-

sponge-spongiomorph knolls of the Northern Limestone Alps of Austria and

Bavaria.

The lower Luning low lying mounds needed little topographic

relief for continued growth. Unhampered growth was caused by intermit­

tent periods of quiescence. The rate of sedimentation, rate of subsi­

dence, and water energy must have been low during biohermal development.

In addition the amount of time when the conditions were optimal must have

been relatively short.

MORPHOLOGY

The morphology of the framework organisms shows a lot of varia­

tion (fig. 8). The most common form is the irregularly laminated corals,

sponges, and spongiomorphs found in the pioneering and colonization

stages.

The irregular laminar forms are very similar to the Malancourt patch reefs of the Middle Jurassic (Hallam, 1975, p. 387) (fig. 9, 10) .

The scale is the main difference. The Cinnabar and Dunlap Canyon mounds

contain corals, 15 centimeters or less in height and one meter in length.

The Malancourt forms are two to three times the length and height. They both exhibit coral cavities, pillars, balls and an equal percentage of matrix between the corals. The modern analog to this morphology is in 66

l o c a l it y Y a Brachiopod b Coral

Coral

Figure 8. Cross sections of spongiomorphids and corals showing the variety of growth forms in Dunlap and Cinnabar Canyons. JURASSIC

Figure 9. Morphologic comparison of Jurassic Malancourt mounds and Karnian Dunlap and Cinnabar Canyons mounds (continued on Figure 10) Malancourt mounds from Hallam, 1975. 68

Figure 10. Continuation of cross sectional views of mound morphology of Cinnabar and Dunlap Canyons. 69 the North Eleuthera Island, Bahamas (fig. 11). The Bahaman reefs exhibit a wide range of forms which change according to genera and depth, and occur on a much greater scale.

DIVERSITY

The total number of species present in the lower Luning of

Dunlap and Cinnabar Canyons does not exceed 70. This is a very low number for the variety of habitats represented. The reefoid habitat itself usually supports hundreds of preservable species. I believe there was a fairly good diversity in the mound facies. The only evi­ dence for this lies in the silicified zones found sporadically in the area. Within these zones the preservation is much better. Many uniden­ tifiable fragments must represent new species yet unknown in the area and only a very detailed study will uncover these new species. On the whole, the silicified zones show a picture of an organically rich environment, which looks impoverished, when viewed through the recrystallized and altered limestones.

MATURITY

The majority of organisms found in the area are mature. Immature specimens of brachiopods, some pelecypods, echinoids (very small spines), and gastropods, are not uncommon. It is not known though, if the echinoid spines and gastropods truly represent immature forms; the gastro­ pods may be smaller mature forms and the echinoid spines may be secondary spines.

SIZE

The size of the individuals are not very large and neither are they unusually small. Elements of the coral and spongiomorphid fauna 1m

P I L L A R S columnar club shaped

1m cjmiL- d~~M e mushroom shaped

P I L L A R ...... S TRUCTURES

plate

10 m

10 m

downward arching mushroom REEFS

10 m

Figure 11. Bahaman reef morphology. Schematic illus­ tration of coral pillars, their combination in pillar structures and of reefs, which are aggregates of pillar structures. From Zankl and Schroeder (1972, fig. 5). 71

are smaller than their European equivalents. Most of the other groups

of organisms are about the same size as their European equivalents. The

area's environment was able to support several large organisms, including

four species of pelecypods ten centimeters in diameter or larger, a

species of gastropod 15 centimeters in length, and the large abundant

sponges.

ASSOCIATIONS

There are many examples of possible close relationships found

within the study area. The relationships include encrusting, embedding,

attachment, possibly entrapping and boring. The large pelecypods, gas­

tropods, and ammonoids have epizoans which may or may not have attached

to the larger shells in life. The epizoans include Placunopsis (which

attached to Lima in Lower Muschelkalk sediments (Seilacher, 1954)),

Lopha and unidentified pelecypods. Many organisms attach to modern

corals including sponges, barnacles and pelecypods. I found many dif­

ferent organisms lying on the surface of the coral or embedded in the

surface; these include spirifers, terebratulids, gastropods, oysters and other pelecypods. In Dunlap Canyon corals and pelecypods were attached to sponges. The corals and spongiomorphids encrusted on one another

frequently. Gastropods and brachiopods are found between the branches of corals and spongiomorphids and may have sought the protection of those branches.

Predation

Organisms which have undergone predation by razing or boring include sponges, corals, spongiomorphids, "pectens," oysters and rarely brachiopods. 72

On sponges, the mode of predation is in the form of razings about three millimeters long just on the surface. The corals and spongiomorphids borings have a variety of shapes and sizes; some being round or oval, others are arcuate or elongate and the sizes vary from a few millimeters to a couple of centimeters. The oyster and brachiopod bored shelled were observed under the microscope. These small borings, of both surficial and deeper depths, show variation in direction of bore and in shape. The "pecten" borings are interesting because the razings are more uniform and are only found in two unidentified species of pelecypod. These razings are one to two millimeters long and form an elongated lens shape. Twenty of these razings can be observed on a square centimeter of shell surface.

There are several organisms responsible for the predations. An acrothorica (a boring naked barnacle with a chitinous attachment disc) may have been responsible for the sponge and "pecten" borings (Seilacher,

1961; Stanley, 1970) . This barnacle burrows and embeds in tissues of mollusks, echinoderms and corals. Modern burrowers and borers of corals include sponges, echinoids, cirrpedia, chaetopods, sabellids, gephyrids, algae, foraminifera and pelecypods. CONCLUSION

The Dunlap and Cinnabar Canyon mounds were formed in warm

euhaline, quiet waters in a gradually subsiding area with relatively slow

sedimentation and periodic changes in deltaic sediment sources. These

changing terrigenous sources caused sediment rhythms composed of a shale and argillite portion and a fossiliferous silty calcilutite portion.

These mounds probably grew below wave base and above the aohotic zone, which is 100 meters in the tropics.

The carbonate rocks are divided into seven facies, which are the

Lopha basal pile, the bindstone facies which is subdivided into the

sponge-Trichites bindstone subfacies and the coral-spongiomorphid bind­ stone subfacies, the Thecosmilia bafflestone, the coral framestone, the

Gryphaea beds, the crinoid flanking lenses and the interreef facies.

The important processes involved in the mound formation are the mechanical accumulation of sediment through current action, trapping and baffling of carbonate sediments, and the stabilization of sediments by surface encrustation. These processes assist in bringing about the vertical biological succession evident in these mounds. The pioneering zone, the first stage in the succession involves local current accumu­ lated oyster shell piles which establish a base for reefoid organisms.

The second zone, the colonization stage, was made up of generalized opportunistic species that tolerated less than optimal conditions.

Trichites, sphinctozoans, Pamiroseris, and spongiomorphids were the primary colonizers. The second phase of the colonization was taken over by Thecosmilia, the sediment baffling coral. Corals and spongiomorphids predominated the diversification zone. These two organisms built the largest portion of each mound. A succession rarely attained by the

73 74 mounds was the domination stage; here the corals flourished and formed a strong framework.

The mound morphology, horizontal layers connected by pillars, balls, or irregular connectors, is also found in the Jurassic Malancourt mounds. The only difference is that the Jurassic forms were on a much larger scale. Another similar morphology, on even a larger scale, is found in the Holocene Bahaman reefs.

The number of taxa for the whole area is only about 70. This is probably only a remnant of a much richer fauna, destroyed by diagenetic processes. Individuals are of normal size and usually are mature.

Predation of corals and spongiomorphids was so extreme, that the debris from predation may have been an important carbonate sediment source.

Sphinctozoans, corals and spongiomorphids were the important frame- builders and they were supported by spirifers, terebratulids, gastropods, echinoids, crinoids, oysters, pectens, and other pelecypods. The organ­ isms had many modes of life including infaunal, semi-infaunal, benthonic vagrant, sessile benthonic, and nektonic swimming. Trophic groups represented are deposit feeders, suspension feeders, carnivores, and scavengers.

This study leaves many problems unanswered such as the depth of water, the exact time of deposition, the diagenetic processes and his­ tory, and an explanation for the lack of bryozoa or algae or other common European reef organisms from the Cinnabar and Dunlap Canyon mounds. SYSTEMATIC PALEONTOLOGY

Phylum PORIFERA Grant, 1872 Class CALCISPONGEA de Blaineville, 1834 Order THALAMIDA de Laubenfels, 1955 Family POLYTHOLOSLIDAE Rauff, 1938 Genus POLYTHOLSIA Rauff, 1938

Polytholsia cylindrica Seilacher, 1962 Plate 7, fig. 4

Polytholsia cylindrica Seilacher, 1962, Die Sphinctozoa, eine Gruppe

fossiler Kalkschwamme: Akad Wissenschaften und der Literatur,

Abh. Mathematusch- naturwissen, Jahr., v. 10, p. 761-762, pi. 5, 6.

Description: Large cylindrical or funnel shaped, central tube of

primary-retrosiphonate type, piercing all chambers except the initial

ones which remain asiphonate, fill structure consisting of tubules

which run in radial directions.

Discussion: Seilacher described two subspecies Polytholsia cylindrica

cylindrica which is cylindrical and Polytholsia cylindrica dilata

which is funnel shaped. A large number of specimens were examined.

In the Cinnabar and Dunlap Canyons the species were as high as 40 cm

and an average of 5 cm in diameter.

Distribution: The Seilacher's type locality is within the lower Luning

Formation in Dunlap Canyon. This species has been found in the Gar­

field Hills in the lower Luning and in the Winnemucca Formation and

the Dun Glen Formation in the Stillwater Range (Pershing County) . All

the occurrences are Karnian. This species is found in almost all

localities. Polytholsia cylindrica dilata is not common and is diffi­

cult to distinguish in outcrop. Polytholsia cylindrica cylindrica

is abundant in the bindstone facies and is also found in the interreef

facies, framestone facies, pelecypod beds and Gryphaea j.acies. 76

Material: UNMSMM 6281, UNMSMM localities 004, 005, 006, 007.

Genus ASCOSYMPLEGMA Rauff, 1938

Ascosymplegma expansum Seilacher, 1962 Plate 7, figure 5

Ascosymplegma expansum Seilacher, 1962, Die Sphinctozoa, eine Gruppe

fossiler Kalkschwimme: Akad. Wissenschaften und der Literatur, Abh.

Mathematisch-Naturwissen. Jahr., v. 10, p. 767-768, pi. 8.

Description: Large disc of fan-shape, consisting of long hollow cham­

bers which are not fusellar, roofs separating adjacent chambers are

thicker and more compact than lateral walls; sheets have been traced

for 6.1 meters in the field, thickness one to two centimeters.

Discussion: This genus is easily distinguished by shape and a more

regular form and sheet-like growth. A large number of specimens

were examined in the field and laboratory. The preservation is good.

Distribution: The Seilacher's type locality is in the lower Luning of

Cinnabar Canyon. In Dunlap Canyon it isn't as common, but it is found

in most localities in the study area. This species is very common in

the sponge-Trichites bindstone and is also found in the pelecypod

beds, Gryphaea beds, and the interreef facies. These sponges have

also been found in the Garfield Hills. They are Karnian in age.

Material: UNMSM 6271 and UNMSM localities 004, 005, 006, 007.

Class SCLEROSPONGIAE Stearn, 1970 Order SPONGIOMORPHIDA Alloiteau, 1952 Family SPONGIOMORPHINAE Freeh, 1890 Genus SPONGIOMORPHA Freeh, 1890

Spongiomorpha dentriformis Smith, 1927 Plate 7, figure 6

Spongiomorpha (Heptastylopis) dentriformis Smith, 1927, Upper Triassic

Marine Invertebrate faunas of North America: U.S. Geol. Survey Prof.

Paper 141, p. 133. 77

Description: Stocks large, arboriform, from 25 to 55 cm long; branches

eight to 10 mm in diameter, diverging from stock at slight angle;

branches roughly parallel; skeleton of pillars with ringlike thicken­

ings, which may produce irregular horizontal plates.

Discussion. The interior of these spongiomorphids is obscured by

recrystallization. Spongiomorpha ramosa Freeh is a similar form but

it is smaller and lacks the density of branching. This species is

found in a light colored matrix and probably played a role in the

baffling process.

Distribution: Smith found this species in the Norian coral zone in the

"Hosselkus" Limestone in Shasta County, California. In the lower

Luning it is uncommon in the framestone facies and bindstone facies and

is rare in all other facies.

Material: UNMSM 6279 two specimens and UNMSM localities 004, 005, and 007.

Spongiomorpha ramosa Freeh, 1890

Spongiomorpha (Heptastylopsis) ramosa Freeh, 1890, Die Korallen der

juvavischen Triasprovinz: Palaeontographica, Band 37, p. 76, text

figs. a-e.

Spongiomorpha ramosa Freeh, Boiko, E.V., 1972, Late Triassic Spongiomor­

phids (Hydrozoa) of the Southeastern Pamirs: Paleontology Jour. no. 2,

p. 161.

Description: Stocks small, irregular, branching, skeleton of pillars with

ringlike thickenings, which may produce irregular horizontal plates.

Discussion: The interior of the specimens is frequently recrystallized

especially in the smaller branches. The branches can be smaller and

also larger than in Freeh's description. Some of the branches are

dicentric and one specimen is a five centimeter thick stock. S_. gibbosa 78

Freeh is a very similar species and the only difference seems to be

that it does not branch. The singular specimens found might or might

not be branching. Another similar species is S. tenuis Smith which

differs in the slenderness of its rods, which is a characteristic

that cannot be differentiated in my suite of specimens.

Distribution: S_. ramosa is rare on Gravina Island, Alaska (Norian) . In

the Karnian of Hungary and the Norian of Greece, this species can also

be found. It is rare in Cinnabar and Dunlap Canyons and found in the

bindstone, interreef, and framestone facies.

Material: UNMSM 6280, three specimens, locality UNMSM 007.

Genus STROMATOMORPHA Freeh, 1890

Stromatomorpha. californica Smith, 1927

Stromatomorpha californica Smith, 1927, Upper Triassic marine inverte­

brate faunas of North America: U.S. Geol. Survey Prof. Paper 141, p.

133.

Description: Large, compact stocks as much as 40 centimeters in width,

consists of pillars whose concentric thickenings lie on the same

levels; laminae are the fusion of filiform tabulae and thickenings.

Discussion: In comparing Shasta County specimens with the lower Luning

specimens, the Shasta specimens were not in true buildups but rather

randomly scattered, so they grew large and were rounded by wear or

had a spherical growth form. Lower Luning specimens had a high dens

ity of borings and were found in corallen mounds, thus with these

limitations they may have been smaller. They are usually in sheet

like growth forms.

Distribution: S. californica is very common in the Norian coral zone

on Gravina Island, Alaska and in the "Hosselkus" Limestone at the 79

mouth of Brock Creek, Shasta County, .California. In the study area

it is common in both canyons and in the interreef facies, framestone

facies and the bindstone facies. In other facies it is rare.

Material: UNMSMM 6291 two specimens, UNMSMM localities 004, 005, 006

and 007. 80

Phylum COELENTERATA Prey and Leuckart, 1847 Subphylum CNIDARIA Hatschek, 1888 Class ANTHOZOA Ehrenberg, 1834 Order SCLERATINIA Bourne, 1900 Suborder FAVIIDA Vaughan and Wells, 1943 Family MONTLIVALTIINAE Dietrich, 1926 Genus THECOSMILIA Milne Edwards and Haime, 1848

Thecosmilia cf. T. fenestrata Reuss, 1854

Calamophyllia fenestrata Reuss, 1854, Beitrage zur Characterisik der

Kreideschichen in den Ostalpen: K. Acad. Wiss. Wien Denkschr., Band

7, pi. 5, figs. 20, 21.

Thecosmilia fenestrata Freeh, 1890, Die Korallen der juvavischen

Triasprovinz: Palaeontographica, Band 37, p. 9, pi. 1, figs. 25-27.

Thecosmilia c f . T_. fenestrata Freeh, Muller, 1936, Triassic coral reefs

in Nevada: Am. Jour. Sci. v. 42, p. 205.

Description: Thick set branching stocks, five to ten millimeters thick,

with numerous septa in four or five cycles, up to 50, of which nine

to 12 stand out as primaries, well developed spines on septa;

branches not widely diverging, up to 90 degrees.

Discussion: These corals are poorly preserved and in most the septa and

other interior structures are no longer visible. The branches are

round to oval shaped with the same size range as described by Freeh

and average five millimeters in diameter. The primaries can not be

seen in these specimens, so the number is questionable. T_. suttonenis

(Clapp and Shimer) , 1911 has fewer septa than T. fenestrata as does

T. clathrata (Emmrick), 1953. T. norica Freeh, 1890 is larger and

more robust. The specimens are closest to T_. fenestrata, but because

interior structure is missing, it cannot be called T. fenestrata as

yet. 81

Distribution. T - .Lenestrutu is very common in tlis Austrian Alus T

fenestrata is rare in the lower Norian coral zone on Gravina Island

and Cook Inlet in Alaska and in the Rheatian of Eastern Persia.

Also, it is found on Vancouver Island and on Timor. Nevada specimens

are dominant in the bafflestone facies and rare in all others.

Material: UNMSM 630i and UNMSM localities 004, 005, 006, 007.

Thecosmilia dawsoni (?) (Clapp and Shimer), 1911

Rhabophyllia delicatula Freeh, 1890, Die Korallen der juvavischen Trias-

provinz: Palaeontographica, Band 37, p. 19, pi. 3, figs. la-c.

Calamphllia dawsoni Clapp and Shimer, 1911, The Sutton Jurassic of the

Vancouver group, Vancouver Island, B.C.: Boston Soc. Nat. Hist.

Proc., v. 34, no. 12, p. 431, pi. 4, fig. 1, pi. 42, fig. 16.

Thecosmilia cf. T_. dawsoni (Clapp and Shimer), Squires, 1956, A New

Triassic coral fauna from Idaho: Am. Mus. Noviates, no. 1797, p.

23, fig. 29, 30.

Description: Irregularly branched, branches three to four millimeters

in diameter; septa 48 in number, two groups of septa, one of which

reaches the columella.

Discussion: Muller identified this coral as T_. delicatula, and Smith

placed it in synonomy with T_. dawsoni. The two species differ in

the mode of branching and in the size of corallites. The specimens

I found have irregular branching and corallites two to six milli­

meters in diameter with 16 to 40 septa. T. delicatula is smaller

than T. dawsoni by a millimeter or so. The corallites of my specimen

are round to elliptical in shape and randomly spaced. T_- recondita

(Laube) , 1865, is also similar to T. dawsoni in having the same num­

ber of septa and size and it is found in the Karnian, so this form 82

may be T. recondite. The poor preservation and lack of comparative

material makes it impossible at this time to positively identify my

specimen.

Distribution: T. dawsoni was first described from the Rheatian stage of

the Tyrolian Alps. In the Norian stage it is found in Idaho and

Vancouver Island. In the Karnian, lower Luning Fm. it is very rare.

Material: UNMSM no. 6277, locality UNMSM 007.

Genus MONTLIVALTIA Lamouroux, 1821 \t — — — — — — — —

Montlivaltia marmorea Freeh, 1890 Plate 3, Figure 5

Montlivaltia marmorea Freeh, Smith 1927, Upper Triassic Marine Inverte­

brate Faunas of North America: U.S. Geol. Survey Prof. Paper 141,

p. 126.

Description: Large single coralla, blunt conical shape: elliptical

cross section; septa very fine, meet along a line, columella lacking.

Discussion: H.W. Turner found this species in Dunlap Canyon and S.W.

Muller reconfirmed the find in 1936. The largest specimens are 15

centimeters in diameter, but they average five to eight centimeters

in diameter. The height of the corals varies and so does the shape.

Some specimens are very blunt, one being ten centimeters in diameter

and only four centimeters in height. Other corals can be taller

than they are wide, one fossil is 15 centimeters tall and nine centi­

meters in diameter, but these examples are not the usual. The number

of septa is unknown due to recrystallization. In eight centimeters

there are at least 100 septa and for this specimen the total septa

may exceed 400. At Steinplatte M. marmorea is nine to ten centimeters

in diameter and has 200 to 300 septa that reach the center 83

Distribution. This species is found at Steinplatte (Rheatian) where it

is uncommon in the rsef calcarenite facies. In the Pilot Mountains

this species is rare, while not restricted areally, it is restricted

to the bindstone, framestone, bafflestone, and interreef facies.

Material: UNMSM 6272, localities UNMSM 004, 005, 006, 007.

Montlivaltia norica Freeh, 1890 Plate 3, figure 2

Montlivaultia capuliformis Reuss, 1854, Beitrage zur Characteristik der

Kreideschichten in den Ostalpen, besonders in Gosauthale und am

Wolfgangsee: K. Akad. Wiss. Wien Denkschr., Band 7, pi. 6, figs.

16, 17.

Montlivaultia norica Freeh, 1890, Die Korallen der juvavischen Trias-

provinc: Palaeontographica, Band 37, p. 39, pi. 3, figs. 9a-b; pi.

10, figs. 1-5; pi. 13, figs. 1-7, pi. 18, figs. 17, 17a.

Stylophyllopsis mojsvari Freeh, 1890, Smith, 1927, The Upper Triassic

Faunas of North America, U.S. Geol. Survey Prof. Paper 141, p. 127,

pi. 118, fig. 10.

Description: Conical form, thick set, irregular elongate elliptical

cross section, septa numerous, at least 150 meeting at a line, no

true columella, monocentric condition prevalent, dicentric and tri-

centric specimens are found; septa in three groups.

Discussion: In the lower Luning the dicentric condition is more common

than the monocentric condition. The sizes and shapes are highly

variable. The specimens are generally in poor condition, as the

total number of septa can only be estimated. Within five milli­

meters there are ten septa, this is the same number as in the Idaho

specimens. 84

Distribution. norica is rare in the lower Norian coral zone in the

Blue Mountains of Oregon and on Gravina Island, Idaho, Alaska and in

Timor. In the lower Norian Zlambach beds of Austria, it is the com­

monest species of coral. This species is common in the reef cal-

carenite facies of the Rheatian Steinplatte reef complex where it

would have experienced moderate agitation. It is also found in the

Rheatian of Eastern Persia. Within Cinnabar and Dunlap Canyons, this

species is rare in the interreef, framestone, bindstone and some

pelecypod beds.

Material: UNMSM no. 62783 localities UNMSM 004, 005, 006, 007.

Genus MARGARASTRAEA Freeh, 1896

Margarastraea norica (Freeh), 1890 Plate 2, figures 1, 2, 3

Latimeandra norica Freeh, 1890, Die Korallen der juvavischen Triaspro-

vinz: Palaeontographica, Band 37, p. 26.

Margarastraea norica (Freeh), Squires, 1956, A new Triassic coral fauna

from Idaho: Am. Mus. Novitates, no. 1797, p. 5.

Description: Compound branching stocks, with elongate calyces merging

into each other, arranged in rows, septa numerous and thin, septa 1.5

centimeters in diameter, calyces vary in size greatly, septa are con­

fluent over the walls.

Discussion: This species is larger and has more septa than M. noric_a

var. minor or M. eucystis Volz. The material is poorly preserved and

recrystallized. The average width of the corallite is four milli­

meters and the length is highly variable, the longest being two centi

meters. In the small corallites, the septa number 40 or more. The

corals are not found in subspherical forms, but in sheets up to ~en

centimeters high. 85

Distribution: This species is found in the Norian beds of the Tyrolian

Alps. In the Dunlap and Cinnabar Canyons area, the abundance and

distribution is obscured by recrystallization. M. norica is found in

the mound facies and the interreef facies. This coral is not one of

the main framebuilders, but may have been locally common.

Material: UNMSM no. 6275, 15 specimens, localities UNMSM 004, 005, 006,

007.

Genus ELYSASTRAEA Laube, 1864

Elysastraea profunda (Reuss), 1854 Plate 3, figure 4

Isastraea profunda Reuss, 1854, Denkschr. K.K. Akad. Wiss., Vienna, v.

7, p. 116, pi. 9, figs. 5, 6.

Isastraea whiteavesi Clapp and Shimer (part), 1911, The Sutton Jurassic

of the Vancouver Group, Vancouver Island, B.C., Proc. Boston Soc.

Nat. Hist., v. 34, p. 429, pi. 40, fig. 9.

Confusastrea cowichanensis (Clapp and Shimer), Smith, (part), 1927,

Upper Triassic faunas of North America: U.S. Geol. Survey Prof.

Paper 141, p. 127, pi. 114, figs. 10-13.

Elysastraea profunda (Reuss), Squires, 1956, A new Triassic coral fauna

from Idaho: Am. M u s . Noviates, no. 1797, p. 25, figs. 48-51.

Description: Polygonal corallites moderately large, 2 to 3.5 milli­

meters in diameter, closely adpressed; walls narrow; confluent septa

continuous over walls, septa 24 to 42, arranged in two groups,

larger lobate septa appear to intermingle with columella.

Discussion: This species is part of a series which is distinguished by

the size of the corallite. The four species involved are E. parva,

E. vancouversis, E. profunda, and E. major. E. vancouversis differs 86

from E. profunda in that it has 20 to 30 septa and is 2 to 4 milli­

meters in diameter. The Cinnabar and Dunlap Canyon specimens have

the same number of septa but the corallites are 1 to 6 millimeters in

diameter, averaging 3 millimeters in diameter. The four species in

the series may not be separate species, because this coral displays a

normal wide range of variation and because size only is a weak cri­

terion for differentiation of species in these corals.

Distribution: This species is rare in the lower Norian coral zone in

Shasta County, California. It is also found in the Norian of Alaska,

Idaho, the Zlambach beds of Fischerwiese in the Tirolian Alps and in

the coral zone on Vancouver Island, B.C. In the Pilot Mountains, this

coral is abundant in the framestone, bindstone, and interreef facies.

Material: UNMSM no. 6276 and localities UNMSM 004, 005, 006, 007.

Elysastraea parva (Smith), 1927 Plate 3, figure 3

Isastraea parva Smith, 1927, Upper Triassic invertebrate faunas of North

America: U.S. Geol. Survey Prof. Paper 141, p. 128, pi. CXIV, figs.

7-9.

Elysastraea parva (Smith), Squires, 1956, A new Triassic coral fauna from

Idaho: Am. Mus. Novitates, no. 1797, p. 25.

Description: Stocks small, irregular, calyces irregular polygonal shapes,

shallow; about one millimeter in diameter; septa arranged in three

cycles, numbering 24.

Discussion: The calyces are half the size of E_- vancouversis. The

stocks found were four millimeters to 15 millimeters thick.

Distribution: This species is found on Gravina Island, Alaska, but is

rare. In the Cinnabar and Dunlap Canyons it is found m the brnd-

stone facies. E. parva is much less common than E_. proj-unda_ and the^ 87

can be found together. This species, as other coral species, is very

difficult to evaluate in terms of abundance, but it apoears to be

rare to uncommon in most areas of the lower Luning Fm.

Material: UNMSM no. 6278, UNMSM localities 004, 005, 006, 007.

Suborder FUNGIIDA Verrill, 1865 Superfamily THAMNASTERIODEA Alloiteau, 1952 Family THAMNASTERIIDAE Vaughan and Wells, 1943 Genus PAMIROSERIS Melnikova, 1971

Pamiroseris rectilamellosa (Winkler), 1861 Plate 1, figure 3 li Thamnastraea rectilamellosa Winkler, 1861, Der Oberkeuper, nach Studien

in den bayrishen Alpen: Deutsche Geol. Gesell, Zeitschr., Band 13,

p. 487, pi. 8, fig. 7.

Thamnastraea alpina Winkler, 1861, idem, p. 487, pi. 8, fig. 8.

Thamnastraea plana Winkler, 1861, idem, p. 488, pi. 7, fig. 9.

Fungiastraea rectilamellosa (Winkler), Melnikova, 1967, New Species of

Scleractinians of the Pamirs: Paleont. Zhur., no. 1, p. 19, pi. 2,

fig. 1.

Pamiroseris rectilamellosa (Winkler), Melnikova, 1971, New data on the

microstructure and systematics on Late Triassic Thamnasteriodea:

Paleont. Zhur., no. 2, p. 21-35.

Description: Stocks flattened, mushroom-like or irregularly convex:

calyces seven or eight millimeters in diameter, without walls,

united by ribs, septa fused in center and resemble a columella septa

number 20 to 26, and form two distinct cycles.

Discussion: The specimens are so poorly preserved that the number of

septa cannot be accurately counted and the calyces fall mostly in tne

lower limit in diameter. These corals are very thin, averaging two

centimeters in thickness. P. norica differs in having iarg^ calces 88

and more distinct cycles of septa.

pistribution: This coral is found in the lower Norian zone in Shasta

County, California and the Zlambach beds of the Fischerwiese in the

Tyrolian Alps. It also occurs in the Rheatian of Eastern Persia and

in the Sueinplatte reef complex. In the lower Luning, it is found

commonly in the bindstone facies. Other facies contain this species,

but recrystallization interferes with an estimation of abundance.

Material: UNMSM no. 6282, localities UNMSM 004, 005, 006, 007.

Pamiroseris rectilamellosa (Winkler) var. minor Freeh, 1890

Thamnastraea rectilamellosa Winkler var. minor Freeh, 1890, Die Korallen

der juvavischen Triasprovinz: Paleontographica, Band 37, p. 62, pi.

17, fig. 12.

Thamnastraea rectilamellosa Winkler var. minor Freeh, Smith, 1927, Upper

Triassic invertebrate faunas of North America: U.S. Geol. Survey

Prof. Paper 141, p. 131, p. 116, fig. 3, pi. 118, figs. 5, 6.

Thamnastraea borealis Smith, Muller, 1936, Triassic coral reefs of

Nevada: Am. Jour. Sci., v. 31, p. 206.

'Thamnasteria smithi Squires, 1956, A new Triassic coral fauna from Idaho;

Am. Mus. Novitates, no. 1797, p. 13-14.

Pamiroseris rectilamellosa (Winkler) var. minor (Freeh), Melikova, 1971,

New data on the micro structure and systematics on Late Triassic Tham-

nasteriodea: Paleont. Zhur., no. 2, p. 21-35.

Description: Stocks small, calyces two to three millimeters in diameter,

18 to 20 septa, pseudocolumella button shaped, septa are thinner than

the interseptal loculi, gives a hirsute appearance to coralla, calyces

united by the septa, having no walls. 89

Discussion * Squires P_. smithi is only slightly different from the

described species. The septa from P. smithi number 13 to 20, from P.

recti lame llosa Winkler var. minor Freeh, Smith 13 to 18, and from the

lower Luning 13 to 20. The calyces are also nearly the same dimaeter.

P. rectilamellosa Winkler var. minor Freeh is three to four milli­

meters in diameter according to Smith, and two to three millimeters

in diameter in Freeh's specimens and the Pilot Mountain specimens.

The main reason Squires proposed a new name was the difference in age.

Freeh's subspecies is only found in the Rheatian of Europe and Squires

believes it could not also be in the Norian. I disagree and believe

the two species are synonymous. Muller identified this coral in the

mounds and called it T_. borealis Smith, 1927. This species is prob­

lematical because the type specimen isn't even in the same genus. T.

borealis has more septa, 24 in number, and has large parallel branches

which anastomose along its length. My specimens are less than ten

centimeters in diameter, are poorly preserved, saucer shaped and one

to three centimeters in width.

Distri hution: This subspecies is found in the lower Norian age "Hossel-

kus" Limestone of the Shasta region, California and also in the same

zone on Gravina Island in Alaska. In Europe, it is found in the Rhea­

tian Starmberger facies. In the lower Luning, it isn t commonly

found. It is found often in the lower bindstone facies and in the

Lopha basal pile, but also in the upper bindstone facies and the

framestone facies.

Material: UNMSM no. 6307 two specimens, UNMSM localities 004, 005, 006,

and 007. 90

Pamiroseris norica (Freeh), 1890 Plate 1, figure 1, 2

Thamnastraea norica Freeh, 1890, Die Korallen der juvavischen Trias-

provinz: Paleontographica, Band 37, p. 63, pi. 18, fig. 10.

Description: Large corallites, 12 to 21 septa showing and confluent

with the septa of the other corallites; corallites 10 to 15 milli­

meters in diameter.

Discussion: These corals are found in the lower Luning as thin or thick

sheets. Muller recognized this coral in the mounds of the Pilot

Mountains.

Distribution: This species is found in the Zlambach beds (lower Norian)

of Austria. In the lower Luning it is infrequently found.

Material: UNMSM no. 6263, localities UNMSM 004, 005, 006, 007.

Suborder ASTROCOENIIDA Vaughan and Wells, 1943 Family ASTROCOENilDAE Koby, 1890 Subfamily ASTROCOENIINAE Koby, 1890 Genus ASTROCOENIA Milne-Edwards and Haime, 1848

Astrocoenia juvavica (Freeh), 1890 Plate 3, figure 1

Stephanocoenia juvavica Freeh, 1890, Die Korallen der juvavischen Trias-

provinz: Palaeontographica, Band 37, p. 38, text figure.

Astrocoenia juvavica (Freeh), Squires, 1956, A New Triassic Coral Fauna

from Idaho: Am. Mus. Novitates, no. 1797, p. 11.

Description: Compact, massive, knobby stocks, with small round calyces

well separated, septa number 24 to 30, styliform columella.

Discussion: The specimens of this species are usually so poorly pre­

served only a faint pattern remains and only the primary septa may be

visible. The better specimens show separation by the walls and 24

septa in two or three cycles in calyces three to four millimeters j.n

diameter. The stocks I encountered were knobby, bulbous, and less 91

sheet like. Squires pointed out that A. shastensis is very similar

in size and number of septa, but he did not mention any of the dif­

ferences.

Distribution. This species was first found in the lower Norian Zlambach

beds of the Fischerwiese in the Tyrolian Alps. It is also found in

the same coral zone in the Cook Inlet, Alaska, and in the Shasta area

of California according to Smith. This coral is abundant in the

framestone facies and bindstone facies of the lower Luning.

Material: UNMSM 6284 UNMSM no. 6284, locality UNMSM 004, 005, 006, 007. 92

Phylum BRACHIOPODA Daniel, 1806 Class ARTICULATA Huxley, 1869 Order SPIRIFERIDA Waagen, 1883 Superfamily SUESSIACEA Waagen, 1383 Family CYRTINIDAE Frederiks, 1912 Genus ZUGMAYERELLA Dagys, 1963

Zugmayerella cf. Z. koessenensis Zugmayer, 1882 Plate 6, figure 6

Zugmayerella koessenensis Zugmayer, 1882, Dagys, 1963, Upper Triassic

brachiopods in the south of the USSR: National Lending Library for

Science and Technology, p. 156.

Description: Small size, semi-pyramidal, tall pedicle valve, flattened

brachial valve; beak tall, straight or recurvate; area wholly or

partly covered with vertical striae, striae become dents in hinge

line; delthyrium open; hinge line shorter than maximum width; dis­

tinct sulcus and fold, sharply delimited from lateral slopes, smooth,

rounded ribs on lateral slopes; growth plates and spine bases

present; five non-bifurcating ribs (average, four to eight ribs on

each lateral slope).

Discussion: The species found in the Pilot Mountains differs from

Zugmayerella koessenensis in being a little larger. The average

height is 25 millimeters and the average width is 20 millimeters .

Also this species has a sharper sulcus and fold which is deeper. It

differs from Zugmayerella uncinata in having more ribs on the lateral

slopes.

Distribution: Z. koessenensis is found in the Norian and Rheatian of

the Alps, Carpathians, the Crimea, Caucasuses, and in the northeast

USSR. The study area species is uncommon in the crinoid facies,

framestone facies and rare in Gryphaea and other pelecypod beds.

Material: UNMSM 6312, UNMSM localities 004, 005, 006, 007. 93

Family SPIRIFERINIDAE Davidson, 1834 Subfamily SPIRIFERININAE Davidson, 1884 Genus GUSERIPLIA Dagys, 1963

Guseriplia multicostata Dagys, 1963 Plate 6, figure 9

Guseriplia multicostata Dagys, 1963, Upper Triassic brachiopods in the

south of the U.S.S.R. : National Lending Library for Science and

Technology, p. 170-171, pi. 16, figs. 1-9.

Description: Large inequivalve shells, tall pedicle, recuvate beak, low

flattened brachial valve; hinge line shorter than maximum width,

cardinal angle rounded, angular ribs on lateral slopes and sulcus and

fold, sulcus is distinct and traceable up to the beak, but not well

separated from lateral slopes, ribs numerous, can bifurcate, 26 to 32

ribs of which 3 to 6 belong to the sulcus, up to 40 millimeters in

width, length inferior to width 8 to 9 length to width.

Dimensions: Only one specimen could be measured, the height of this

specimen was 25 millimeters and the width was 26 millimeters.

Discussion: The shells are not as large as the type specimens and the

ribs number 25 to 33 and 6 to 10 on the sulcus. Since only five

examples were collected and these were partly broken, it is amazing

that the samples had so few differences. Larger specimens were seen

in the field. Close species like G_. bittneri have fewer ribs and are

significantly smaller and Spiriferina pectinata Bittner, 1890, is

also smaller and has a less recurvate beak and a less clearly devel­

oped sulcus and fold.

Distribution: This species has been found in the Norian and Rheatian

beds of Northwestern Caucacus. This North American occurrence is new.

This species is rare in the mound facies, but is not restricted

areally. 94

Material: UNMSM no. 6309, localities 007, 006, 004, 005.

Guseriplia bittneri Dagys, 1963 Plate 6, figure 10

Guseriplia bittneri Dagys, 1963, p. 174, pi. 14, figs. 10-12. Upper

Triassic brachiopods in the south of the U.S.S.R. : National Lending

Library for Science and Technology.

Spiriferina gregaria Suess, Muller, 1936, Triassic coral reefs of

Nevada: Am. Jour. Sci., v. 31, p. 204.

Description: Strongly inequivalve shell, as much as 16 millimeters long

and 17 millimeters wide, outline rounded-rhombic, length equals

width or is a little less, straight hinge line, pedicle valve taller

than brachial, beak broad, straight or slightly recurvate; area

slightly concave, not limited well from lateral slopes, delthyrium

open; sulcus shallow, rounded, fold narrow; sulcus and fold each

carry two to three ribs, five to seven ribs cover each of the lateral

slopes.

Discussion: Muller identified these brachiopods as Spiriferina gregaria

Suess which is thought to be a transition form of the above described

species. S. gregaria differs in having a more distinct sulcus and

fold and in having ribs in the axial parts of the fold and sulcus.

Dagys states that until internal comparison is made of the similar

Spiriferinas and compared to his new genus that he does not know how

the two genera are related. I'm not sure if there are actually any

any differences between S_. gregaria and G_. bittneri, when comparing

pictures and the variation among my specimens. But the majority fell

into the range of G. bittneri. My specimens have recurvate peaks,

most have three ribs on the sulcus, and the dimensions can t b_

measured because the specimens are deformed and broken, but they are 95

less than 17 millimeters long and airs wider than thsv ai"s long.

Distribution. bittnsri is found in ths Norian~Rheatian bsds of

Czechoslovakia and Caucasus. S_. gregaria is found in the lower

Karnian of Spiti and in Bakony.

Material: UNMSM no. 6371, localities UNMSM 004, 005, 006, 007.

Genus SPIRIFERINA d'Orbigny, 1847

Spiriferina sp. Plate 7, figures 5, 7, 8, 10

Description: Small, nearly equivalved, valve convexity subequal, shell

has elongated oval outline, height less than depth or width, widest

at straight hinge line; maximum height of pedicle valve central,

pedicle valve may be taller and more convex, lateral parts of pedicle

valve end in sharp auricles, usually broken off, sulcus indistinct

and delimited from lateral slopes, sulcus rounded, medial rib in

center, which starts at beak; five to seven ribs on lateral slopes;

beak small recurvate; delthyrial aperture is triangular and area

usually open, area may be covered by pedicle and brachial beak, area

four times wider than tall, area weakly striated; brachial valve

convex, beak small, fold indistinct, not clearly delineated from

lateral slopes, two ribs in fold, five to seven ribs on each lateral

slope; microsculpture of fine papillae which may have been bases for

/ spines.

Dimensions: Largest specimen one centimeter tall, one centimeter deep,

and 15 millimeters wide; smallest specimen one centimeter wide, five

millimeters tall and five millimeters deep.

Discussxon: Two other species resemble my specimens but each one has

differences which are important. S_. abichi has the narrow area and 96

other external characteristics but has fewer lateral ribs. Spirifer-

j-na (Spiriterina) elesmersis Logan, 1967 is found in the Ladinian and

possibly the Karnian has the same external characteristics and is the

same size but with one or two more lateral ribs and the area is

taller.

Distribution: The species is uncommon in crinoid facies, interreef

facies, framestone and bindstone facies and is rare in all other

facies. This species is not restricted in area.

Material: UNMSM no. 6308, localities 004, 005, 006, 007.

Order TEREBRATULIDA Waagen, 1883 Suborder TEREBRATULIDINA Waagen, 1883 Superfamily TEREBRATULACEA Gray, 1840 Family TEREBRATULIDAE Gray, 1840 Subfamily TEREBRATULINAE Gray, 1840 Genus ADYGELLA Dagys, 1963

Adygella julica (Bittner) 1890

Terebratula julica Bittner, 1890, Brachiopoden der alpinen Trias K. K.

geol. Reichsanstalt Wien Abd., vol. 14, p. 125, pi. 4, fig. 14 and

15; pi. 39, figs. 15, 16.

Dielasma julicum Diener, 1908, Ladinic, Carnic, and Noric faunae of

Spiti: India Geol. Survey Mem., Palaeontologia Indiea, ser. 15, vol.

5, Mem. 3, p. 92, pi. 16, fig. 4.

Adygella julica Dagys, 1963, Upper Triassic Brachiopods of the southern

U.S.S.R.: Akad. Nauk. Sibir. otdel., p. 167.

Description: shell small, suboval; beaks slender, curving forward only

slightly, margins strongly plicate, form two marginal ridges on

dorsal valve, shell a little longer than broad.

Dimensions: length-26.5mm, breadth-23mm, thickness-13mm.

Discussion: Muller identified this species in the lower Luning fauna. 97

Distribution. This species is common and is found in many places. It is

found in Hungary, India, Spiti, Austria, and in the Shasta area,

California. Normally it is found in Karnian deposits.

Material: UNMSM 6310, localities UNMSM 004, 005, 006, 007.

Genus TEREBRATULA Muller, 1776

Terebratula sp. undet. Plate 6, figure 1, 2, 3, 4

Description: Medium size, valves very inflated to being only slightly

inflated, pedicle valve always more inflated, both valves with 8 to

16 ribs, beginning half way down the shell or one fourth of the way

from the beak, beak prominent and recurvate, sometimes the central

ribs are prominent.

Dimensions: breadth height wide

Specimen A 25 mm 25 mm 15 mm Specimen B 26 mm 30 mm 17 mm Specimen C 22 mm 25 mm 15 mm

Discussion: I looked at 50 or more specimens and the variation was

increditable, but there seemed to be transition specimens, so I did

not separate the suite into more than one species. I have not seen

any specimens that resemble this one. The material was good.

Distribution: This species is found all over the study area. It is

common in areas where other terebratulids are found, such as some of

the pelecypod beds.

Material: UNMSM no. 6303, localities 004, 005, 006, 007. 98

Phylum MOLLUSCA Class BIVALIA Linne, 1758 Order MYTILOIDA Ferussac, 1922 Superfamily PINNACEA Leach, 1819 Genus PINNA Linne, 1758

Pinna sp. undet.

Description: Wedge-shaped, large, angular; radial ribs not very promi­

nent, shell divided into three flat or slightly concave surfaces

divided by sharp angles 100 degrees or so; 11 centimeters plus long

and five centimeters plus in breadth; shell thin and asymmetric.

Discussion: The one specimen is in poor condition and broken, thus

identification to species level is not appropriate.

Distribution: Fragments were found in the pelecypod beds of locality

004-M and 006-C. Pinna is a cosmopolitan genus found in the whole

Mesozoic.

MATERIAL: UNMSM no. 6264, locality UNMSM 004 and 006.

Genus TRICHITES Voltz, 1833

Trichites sp. undet. Plate 3, figure 4, 5

Description: Large, irregularly trapeziform, more or less inequivalve;

margins with irregular undulations, closed or narrowly gaped; poste­

rior adductor muscle scar deep, much extended in radial direction,

surface uneven, bifurcating ribs, numbering 12 to 15, shell very

thick, composed of fibrous calcite, commonly found only as fragments,

shell 11 to 31 centimeters tall; 0.8 to 5 centimeters in thickness.

Dimensions: breadth height

Specimen A 9.2 cm 11+ cm Specimen B 8.6 cm 13+ cm Specimen C 8.+ cm 14+ cm

Discussion: The whole specimens found are not truly representative

because the smaller shells had a better chance to be preserved. In 99

the field broken specimens represented much larger individuals. The

anterior ends of these Trichites are broken off, because that end is

buried and becomes worn by corrosion and is sealed off by partitions.

A species name has never been assigned to this form, though it has

been known in the Upper Triassic of Nevada for many years. This form

was first found by Stanton (1926). It resembles T. seebach Bohm in

shape and sculpture, which is found in the Jurassic sediments of

Europe.

Distribution: Trichites is found in the Upper Triassic to Lower

Cretaceous sediments of Europe, Asia, North Africa, East Africa, and

North America. In Nevada, Trichites is found in the Dun Glen Forma­

tion (Karnian) in the West Humbolt Mountains and in the Luning Forma­

tion in the Shoshone Mountains. This form is abundant in the sponge-

Trichites bindstone. It is uncommon in the pelecypod beds and inter­

reef facies. Trichites is rare in the framestone facies, coral-

spongiomorphid bindstone, Gryphaea facies, and crinoid facies.

Material: UNMSM no. 6259, eight specimens, localities UNMSM 004, 005,

006, 007.

Family MYTILIDAE Rafinesque, 1815 Subfamily MYTILINAE Rafinesque, 1815 Genus MYTILUS Linne, 1758

(?) Mytilus sp. undet. Plate 5, figure 4

Description: Mytiliform with anterior twisted beaks terminal, surface

smooth with faint growth lines, thin shells.

Dimensions: height to beak width of shell

Specimen A 3.2 cm 2.1 cm Specimen B 3.2 cm 2.4 cm Specimen C 1.8 cm 1.4 cm Specimen D 2.8 cm 2.4 cm 100

Discussion; No internal structure can be discerned and the majority of

the specimens are broken. Without the internal characteristics, the

genus identification cannot be completed. In outcrop, these shells

are recognizable by the sheen made by the shell structure.

Distribution: The lower Luning species is found in the framestone

facies, interreef facies, bioclastic beds, bindstone facies and

pelecypod beds in all localities. Their relative abundance is too

difficult to determine.

Material: UNMSM no. 6252, six specimens, localities UNMSM 004, 005, 006,

007.

Order PTERIODA Newell, 1965 Suborder PTERIINA Newell, 1965 Superfamily PTERIACEA Gray, 1847 Family PTERIIDAE Gray, 1847 (1820) Genus PTERIA Scopoli, 1777

(?) Pteria sp. undet.

Description: Obliquely ovate, moderately inflated; elongate posterior

wing, exterior commonly smooth except for growth lines, anterior wing

smaller, breadth eight millimeters, height 31 millimeters, posterior

wing 18 millimeters long.

Discussion: The single specimen is an exterior mold with parts of the

wings broken off. The exterior features indicate this genus, but

without information about the interior features, the genus will

remain in question.

Distribution: The specimen came from locality MSMM 005-P in an

argillaceous limestone pelecypod bed. The genus can be found from

the Triassic to the Recent and is cosmopolitan.

Material: UNMSM no. 6253, UNMSM locality 005. 101

Superfamily PECTINACEA Rafinesque, 1815 Family ENTOLIIDAE Korobkov, 1960 Genus ENTOLIUM Meek, 1865

Entolium sp. cf. E. subdemissium (?) Graf von Muenster, 1892

Entolium subdemissium Graf von Muenster, Bittner, 1895, Lamellibranchi-

aten der Alpinen Trias; K.K. Geol. Reichsanst. Wien, Jahrb., vol. 18,

no. 1, p. 161, pi. 19, fig. 29.

Entolium cf. subdemissium Graf von Muenster, Diener, 1908, Ladinic,

Carnic, and Noric fauna of Spiti: Paleontologia Indica. v. 5, Mem. 3,

p. 138, pi. 24, fig. 12.

Entolium sp. of E_. subdemissium, Graf von Muenster, de Cserna, 1961,

Fossil Fauna of Santa Clara Formation (Carnian) of the state of Sonora

Paleontologia Mexicana, no. 1, p. 28, pi. 1, fig. 7, 8.

Description: Very flat, nearly smooth valves, flat radial furrows sepa­

rating the lateral parts from convex central area, higher than broad,

hinge line straight, equal wings, faint concentric striation.

Dimensions: Breadth Height

Mexican specimens 10.5mm 11mm +11.3mm +12mm Dieners' Megalodon fauna 17mm 19mm Dunlap and Cinnabar Canyons 24mm 27mm Specimen A 21mm 24mm Specimen B

Discussion: Only two specimens have been found in the lower Luning area.

Both are too poorly preserved to identify the species. My specimens

are larger than the other examples and it is not known if they display

the most important dianostic feature of a hinge crura.

Distribution: This species is found in the St. Cassian (Karnian) beds in

north Tirol, in the Middle Ladinian to Carnic Myophorian beds o^

Southeast Asia, the Rheatian Megalodon beds of Spiti, China and

Indonesia. 102

Material: 6258 UNMSM, localities 004,

Entolium sp. undet. Plate 4, figure 1

Description. Shell nearly smooth with faint radial end even fainter con-

centric elements, at irregular intervals some radial ribs stand out,

ribs (radial) number over a 100, shell very smooth with weathering,

irregular crenulations on some shells; lateral furrows distinct; hinge

line straight or nearly so; wings with concentric ornamentation, shells

flattened and have more breadth than height; variation in size;

general shape bulbous; equivalvea.

Dimensions: height breadth length of wing thickness

Specimen A 9.3cm 2 .2cm Specimen B 10.4cm 1.0cm Specimen C 4.5cm 5.0cm Specimen D 4.0cm

Discussion: Most specimens are broken and no interior structure has been

seen. The external features are definitely those of Entolium.

Distribution: This species was found mostly-in one locality, and is rarely

in a variety of pelecypod beds. The locality is MSMM 004-M which also

contains large gastropods and other pectinids and fragments of possible

megalodont pelecypods.

Material: UNMSM 6250, UNMSM locality 004, 006.

Family PECTINIDAE Rafinesque, 1815 Genus CHLAMYS (CHLAMYS) Roding, 1798

Chlamys (Chlamys) sp. A Plate 5, figure 5

Description: Shell a tiny bit oblique, sculpture of radial and weak con­

centric elements, margin scalloped, one auricle larger than the other;

radial elements on wings; height 14 millimeters, breadth 15 milli- /■ meters; hinge line straight. Discussion: Only one specimen was found of this species, and this was

found in a silty pelecypod bed. The preservation was not good enough

to determine the species.

Distribution. This subgenus is cosmopolitan from the Triassic to Recent

Material: UNMSM no. 6266, UNMSM 004-M.

Chlamys (Chlamys) sp. B Plate 5, figure 6

Description: Sculpture of radial and concentric elements, some radial

ribs are more prominent, shell more convex towards the center of the

shell; wings display concentric elements; hinge line straight; wings

inequal, right auricle margin slopes outward, left auricle slopes

toward the shell, left auricle more prominent.

Dimensions: height breadth

Specimen B 2.7 cm Specimen C 2.7 cm 2.0 cm Specimen D 1.3 cm 1.2 cm Specimen E 3.5 cm

Discussion: Pour whole specimens were found as well as several b;

shells. The difference between this species and species A is:

(1) the angle of the wings are different, (2) the ornamentation of

the wings differs in that species A has radial ornamentation and

species B has concentric wing elements, and (3) the margin is scal­

loped on species A and not on species B.

Distribution: This species is found in pelecypod beds of the lower

Luning.

Material: UNMSM no. 6265, localities UNMSM 005, 004. 104

Family TERQUEMID11DAE Cox, 1964 Genus 7PLACUNOPSIS

PPlacunopsis sp. undet. Plate 4, figure 6

Description: Small, suborbicular or ovate, subequilateral, not auricu-

late; attached by almost the whole valve; upper valve flat to strong­

ly inflated, with distinct, not quite marginal umbo; adductor valve

quite large, submedial in position; no well defined cardinal area:

ornamentation of irregular threads (radial): ostracum foliaceous.

Dimensions: height breadth

Locality L 2.5 cm 2.0 cm Locality M Specimen A 2.8 cm 2.5+ cm Specimen B 5.5 cm 5.0 cm Locality C 3.0 cm 2.3 cm Locality P 3.2 cm 4.0 cm

Discussion: This genus was found attached to Lima shells in the Middle

Triassic Muschelkalk beds (Seilacher, 1954). In the Dunlap and

Cinnabar Canyons they are attached to ammonites, reptile vertebra and

gastropods. Not enough interior structure is present to identify it

to species level. The question mark in front of the genus means the

genus is in question as far as authors of the Treatise of Invertebrate

Paleontology are concerned.

Distribution: The genus is cosmopolitan in the Middle Triassic and

Upper Triassic. In the study area, it is common in the pelecypod oeds

in silty limestones.

Material: UNMSM no. 6255, localities 004, 005, 006, 007. 105

Superfamily LIMACEA Rafinesque, 1815 Family LIMIDAE Rafinesque', 1815 Genus LIMA Bruguiere, 1797

Lima sp. undet. Plate 4, figure 6

Description: Shell convex and subtrigonal in shape; radial ribs number

15, with finer radial elements near the steep lateral slopes.

Discussion: One specimen was found, an exterior mold with broken

auricles. It was found in an argillite. The shell is 14 millimeters

in height and 12 millimeters in breadth.

Material: UNMSM 6268, locality UNMSM 004.

Genus MYSIDIOPTERA Salomon, 1895

Mysidioptera sp. undet.

Description: Ovate to suborbicular, postdorsal margin rather elongated,

posterior wing not clearly demarcated from body, anterior auricle

absent, radial striae on shell, shell height 10 millimeters, breadth

15 millimeters.

Discussion: One whole specimen was found. The specimen is not in good

condition, so identification to genus was all that was possible.

Material: UNMSM 6253, locality UNMSM 007.

Order TRIGONIODA Dali, 1889 Superfamily TRIGONIACEA Lamarck, 1819 Family MYOPHORIIDAE Bronn, 1849 Genus MYOPHORIA Bronn in Alberti, 1834

Myophoria sp. undet. Plate 5, figure 2

Description: Trigonallv ovate, very inequilateral; flanks with seven

ribs, with smooth, commonly shallowly concave interspaces; margin

scalloped; 25 millimeters high and 30 millimeters in breadth.

Discussion: One specimen was all that was collected. M. boesei u rech) ,

1907 is the closest species, but it has five ribs and is anout half 106

the size. The shell is encased in argillite.

Material: UNMSM 6262 locality UNMSM 004.

Family TRIGONIIDAE Lamarck, 1819 Plate 5, figure 1

Two different forms have been found that belong in the Trigoniidae

family. One form resembles Prorotrigonia in having no defined carina

on the margin and in having concentric ornamentation which does not

reach the smooth part of the shell. But it doesn't seem to have the

same elongated shape. The shape is difficult to ascertain because

■ the shells are broken. These shells are small being only two centi­

meters in greatest diameter. The sample was found in locality MSMM

006-C in the shaly pelecypod beds. The other example is an exterior

mold found in a bioclastic limestone. The ornamentation is predomi­

nately radial with a little concentric sculpture near the hinge.

The carina is not prominent and the flank is devoid of ornamentation.

The shell is 2.2 centimeters tall and 2.3 centimeters in breadth and

the shell is not highly inflated.

Material: 6260 UNMSMM, locality 006 UNMSM

Subclass HETERODONTA Neumayr, 1884 Order VENEROIDA H. Adams and A. Adams, 1856 Superfamily CARDITACEA Fleming, 1820 Family CARDIDAE Fleming, 1828 Subfamily CARDITESINAE Chavan, 1952 Genus CARDITA Bruguiere, 1758

Cardita sp. undet. Plate 4, figure 2

Description: Transversely inequilateral, trapezoidal, with nodulose

radial ribs.

Discussion: The shells vary in size and are more elongated than other

specimens I have looked at. The length varies from two to four centi

meters, the width ranges from one to three centimeters. The material 107

is poor and most of the whole specimens are interior molds.

Distribution: In the lower Luning the species is found in the limestone

beds.

Material: UNMSM no. 6263, localities 004, 005, 006, 007.

Order HIPPURITOIDA Newell, 1965 Superfamily MEGALODONTACEA Morris and Lyett, 1853 Family MEGALODONTIDAE Morris and Lyett, 1853

The shell is thin, large, gibbose, subtrigonal or ovate with prosogyrous

beaks and weak concentric folds. The only thin shelled megalodonts

are in the genera Megalodon Sowerby, 1827 and Pomarangina Diener,

1908. The height of the beak is 14 cm and 12 cm across the shell.

One specimen has been found in locality UNMSM 004-M which is a

pelecypod bed with large forms of gastropods and pelecvpods. This

specimen is in poor condition and shows no internal features. Mega­

lodonts are commonly found in Triassic biohermal areas.

Material: UNMSM no. 6269, locality UNMSM 004.

Subclass ANOMALODESMATA Dali, 1889 Order PHOLADOMYOIDA Newell, 1965 Superfamily PHOLADOMYACEA Gray, 1847 Family PHOLADOMYIDAE Gray, 1847 Genus PHOLADOMYA Gray, 1847

(?) Pholadomya sp. undet.

Description: Elongate-ovate, medium size or large, strongly inequi­

lateral, valves gape posteriorly; ornamentation of radial ribs of

ridges; narrow anterior gape; shell thin.

Discussion: Shells are thicker than they should be in this genus and

the descriptions of different genera in the family are very similar

in external features. Material is in poor condition, but the valves

remained together encased in hard limestones. The rinbing of these

shells begins at the ends of the shells not the beak region. The 108

anterior and posterior ends are somewhat pointed and the hinge line

is straight. A similar genus to which these forms might be assigned

is Homomya Agassiz, 184j which differs in prominence of umbones and

lacks radial ribbing.

Dimensions: length heignt to beak

Specimen A 8.0 cm+ Specimen B 10.0 cm 4.0 cm Specimen C 11.0 cm+

Distribution: The genus is cosmopolitan in the Upper Triassic. The

form is rare in the Cinnabar and Dunlap Canyons area. It is found

in pelecypod beds and bioclastic beds.

Material: 6251 UNMSM no., locality 004, 005 UNMSM.

Suborder OSTREINA Ferussac, 1822 Superfamily OSTREACEA Rafinesque, 1815 Family OSTREIDAE Rafinesque, 1815 Subfamily LOPHINAE Vyalov, 1936 Genus LOPHA Roding, 1798

Lopha montiscaprilis (Klipstein), 1843 Plate 5, figure 3

Ostrea montis caprilis Klipstein, Bittner, 1908, Lamellibranchiaten aus

der alpinen Trias, pt. 1: Revision der Lamellibranchiaten von St.

Cassian: K. K. Geol. Reichsanst., Abh., v. 18, no. 1, p. 70, pi. 6,

figs. 14-18.

Lopha cf. montis-caprilis (Klipstein), Newton, 1923, p. 303, pi. 9,

figs. 1, 2.

Ostrea (Lopha) montis caprilis Klipstein, Cox, 1924, A Triassic fauna

from the Jordan valley: Annals and Mag. Nat. Hist., ser. 9, v. 14,

p. 65, figs. 9-11.

Lopha montiscaprilis (Klipstein), Kobayashi and Toriyana, 1973, Some

Triassic Bivalves from Malayain Contributions to the Geology and

Paleontology of Southeast Asia vol. 12, p. 137, pi. 19, figs. 27-31. 109

Description: Elongate to subcircular in outline, usually taller than

long, left valve moderately inflated, right valve slightly concave

or nearly flat with a wide flat or concave attachment area on umbonal

region of left valve; posterior adductor scar circular in outline and

impressed on internal mold; 20 or more angular ribs inserted by a few

secondary ribs on marginal area.

Dimensions: length height

Malayan sp. 15 mm 21 mm left valve II II 8 mm 11.5 mm " " II II 10 mm 17 mm+ right valve Lower Luning Specimen A 10 mm 18 mm Specimen B 9 mm 28 mm Specimen C 18 mm 21 mm

Discussion: The specimens vary in shape with the environments in which

they are found When found alone they are inflated and nicely ribbed

but in the Lopha basal pile they are dominant and crowded, here they

are flattened and xenomorphic, showing only a few ribs.

Distribution: This species is found in the Upper Karnian of Europe, the

Ladinian-Karnian of Southeast Asia, and the Jordan Valley. It is

found in various Karnian age rocks in Nevada including the lower,

middle, and upper parts of the Luning Formation. Lopha is rare in

most facies but is found in argillites to purer limestones. Lopha

dominates the Lopha basal pile, where it is approximately 90 percent

of the fossil content. The earliest Lophas are supposed to be in the

early Karnian but Kobayashi and Toriyana claim to have found them in

the Ladinian. This moves back the oyster history and might change

the ages of beds dated by Lopha remains.

Material: 6256 UNMSM, UNMSM localities 004, 005, 006, 007. 110

Family GRYPHAEIDAE Vyalov, 1936 Subfamily GRYPHAEINAE Vyalov, 1936 Genus GRYPHAEA Lamarck, 1801

Gryphaea (Gryphaea) sp. undet. Plate 4, figure 3

Description: Small, lacking radial ribs, costellae, or threads, with

evanescent to shallow radial posterior sulcus and posterior flange

not attached; high narrow shape to being broader than high; right

valve concave, vertical— oval to spatulate, truncated by hinge, has

appressed or nonappressed growth squamae; left valve smooth or with

low smooth irregular concentric growth welts.

Discussion: There is a lot of variation in size and shape, the longest

specimen is 25 mm. The height varies from 5 millimeters to 15 milli­

meters. The width varies from ten millimeters to 20 millimeters.

Because of the wide range of variation of this species it is diffi­

cult to compare it to other species. Muller originally discovered

Gryphaea in the Luning Formation of the Cedar Mountains. It is very

possible that this species has not been named as yet.

Distribution: Gryphaea (Gryphaea) is common in the Triassic boreal

province. In the lower Luning they are restricted to certain beds

where they are dominant.

Material: UNMSM no. 6302, localities UNMSM 004, 005, 006, 007.

Class GASTROPODA Cuvier, 1797 Order ARCHAEOGASTROPODA Thiels, 1925 Suborder PLEUROTOMARIINA Cox and Knight, 1960 Superfamily PLEUROTOMARIACEA Swainson, 1840 Family LOPHOSPIRIDAE Wenz, 1938 Subfamily RUEDEMANNIINAE Knight, 1956 Genus WORTHENIA deKoninick, 1883

(?) Worthenia sp. undet.

Description: Turbinate, four volutions, spire flatly conical; fine con­

centric ornamentation and oblique ornamentation on each whorl, first Ill

whorl with pronounced keel.

Dimensions: width at first whorl height

Specimen A 2.2 cm 2.3 cm Specimen B 1.5 cm 2.5 cm

Discussion: The specimens resemble Worthenia, but with only three poor

specimens all that can be stated is that they are Worthenia-like.

The suite of specimens are taller in comparison to their width than

the species of Worthenia I have examined.

Distribution: These gastropods are rare but can be found in the mound

facies.

Material: UNMSM no. 6321, localities UNMSM 004 and 006.

Suborder Doubtful Superfamily CRASPEDOSTOMATACEA Wenz, 1938 Family CRASPEDOSTOMATIDAE Wenz, 1938 Genus BROCHIDIUM Koken, 1889

Brochidium spinosum Korner, 1937

Brochidium spinosum Korner, 1937, Marine (Cassianer-Raibler) Trias am

Nevada de Acrotambo: Palaentographica, v. 86, p. 207, pi. 13, fig. 6.

Description: Discoidal, evolute, apical and basal faces concave; heavy

sculpture, equally spaced ribs parallel to whorls, number 10 on the

first whorl, nodes perpendicular to these ribs encircle most of the

whorl, nodes more closely spaced as whorls become smaller; four whorls.

Dimensions: The greatest diameter 18mm, greatest width 5mm.

Discussion: Specimens of this species were found by Korner, 1937 and by

Cox, 1940, p. 36. Korner found the species in Nevada de Arcotambo,

Peru and Cox found it in Hacienda Huanca, Peru. In Peru it is asso­

ciated with Spondylospira in light limestones and is missing from the

Myophoria lens. Only one nearly whole specimen has been found in the

Cinnabar and Dunlap Canyons. The cross sections of this species are 112

distinct and many of these were observed.

Distribution: The genus is restricted to Triassic to Jurassic age

strata. The species is found in the Upper Triassic of Peru. In the

lower Luning it is found in the framestone facies, bindstone facies

and the interreef facies. It is most commonly found in the interreef

facies, here it is rare to uncommon.

Material: UNMSM 6285, localities UNMSM 004, 007.

Class CEPHALOPODA Cuvier, 1797 Order AMMONOIDEA Suborder CERATITINA Hyatt, 1880 Superfamily ARCESTACEAE Mojsisovics, 1875 Family ARCESTIDAE Mojsisovics, 1875 Genus ARCESTES Suess, 1865

Arcestes sp. undet.

Description: Smooth many-whorled ammonite; suture ammonitic, lobes and

saddles triangular, septa closely spaced; involute.

Discussion: Five specimens were collected and very little shell is left

and on some the suture is the only diagnostic feature present. The

suture was different than the other species found in North America.

Material: UNMSM no. 6296, locality 004, six specimens.

Family CLADISCITIDAE Zittel, 1884 Genus PARACLADISCITES Mojsisovics, 1896

Paracladiscites sp. undet.

Description: Involute, robust, with flattened whorl sides and venter;

suture with retracted suspensive lobe, whorl section subrectangular;

suture ammonitic; smooth conch.

Discussion: One specimen was found in the lower Luning and identified

by the shape and by the partial suture showing. The ammonite is nine

centimeters in diameter and four centimeters wide. 113

Distribution: This genus is found in the Alps, Timor, Himalayas, and in

Nevada at the New Pass area. The genus ranges from the Carnian to

the Norian.

Material: UNMSM no. 6297, locality UNMSM 004-M.

Superfamily TROPITACEAE Mojsisovics, 1875 Family HALORITIDAE Mojsisovics, 1893 Subfamily HALORITINAE Mojsisovics, 1893 Genus JUVAVITES Mojsisovics, 1879

Juvavites sp. undet. Plate 7, figure 1

Description: Involute, subglobose, some flattened to subdiscoidal; whorl

side with dichotomous ribs which pass over venter and may be dis­

rupted along venter; suture ammonitic.

Discussion: Two nearly complete small specimens were collected. They

both show the suture and ornamentation. They are three centimeters

in diameter. The sutures did not match any compared.

Distribution: The genus is found in the Carnian and Norian in the Alps,

Timor, Alaska, Sicily and California.

Material: UNMSM no. 6283, localities UNMSM 004, 006.

Superfamily CERATITACEAE Mojsisovics, 1879 Family CARNITIDAE Arthaber, 1911 Genus NEOCLYPITES Spath, 1951

Neoclypites desertorum Johnston, 1941

Metahedenstroemia? desertorum Johnston, 1941, Trias at New Pass (lower

Karnic Ammonoids), Nevada: Ph. D. dissertation Catholic Univ. of

America, p. 17, pi. 60, figs. 6-8, pi. 61, fig. 1-4, pi. 63, fig. 3.

Description: Compressed discoidal, very involute with umbilicus almost

closed, the venter is narrow, not sharpened but flattened or grooved,

with angular shoulders, the umbilicus is steep-sided with rounded

shoulders, no ornamentation, septae are ceratitic, multilobate, with 114

rounded saddle and toothed lobes, suture lines overlap, occasional

interferences by one suture line with its neighbor.

Discussion: Eight fragments were found and identified mostly on the

basis of the suture pattern. The material widely scattered, no

facies or stratigraphic zone had more fragments than another.

Distribution: This species is found in the Lower Triassic and the

Karnian, of Albania and Nevada at South Canyon and now in the lower

Luni'ng Fm. of Karnian age.

Material: UNMSM no. 6289, localities 004, 005, 006, 007.

Subclass DIBRANCHIATA Order BELEMNOIDA Family BELEMNITIDAE Genus ATRACITES Gumbel, 1861

Atracites sp. undet.

Description: Long phragmocone and short guard, chambered phragocone,

long and slender, has concave septa.

Discussion: Five Atracites were collected, but they are lacking the

finer features and therefore can not be assigned a species name.

Distribution: Not surprisingly they are rare and found in any kind of

lithology in the lower Luning.

Material: UNMSM no. 6304, localities UNMSM 006, 005, 007.

Subclass NAUTILOIDEA Agassiz, 1847 Order and Family Uncertain Genus CONCHORHYNCHUS de Blainville, 1827

Conchorhynchus sp. undet.

Description: Inferred lower beak subrhombic in outline, thin, uppe^

dorsal side gently concave, surface sloping to shallow median furrow

edges near tip; lower side transversely slightly convex, mid line

marked by keel with short side ridges at acute angle from keel. 115

Discussion; This form is a supposed lower jaw. The whole fossil only

extends four millimeters in any direction. The condition of the

fossil is fair.

Distribution: This form can be found in Upper Permian to Middle

Triassic sediments in Europe and North America. I'm sure it is not

restricted to the Middle Triassic but just so rare that it wasn't

found before.

Material: UNMSM no. 3606, locality 006. 116

Phylum ECHINODERMATA Class ECHINOIDEA Leske, 1778 Subclass PERISCHOECHINOIDEA M'Coy, 1849 Order CIDAROIDA Claus, 1880 Family ClDARIDAE Gray, 1825 Subfamily CIDARINAE Gray, 1825 Plate 2, figure 2, 3

Many spines were found but no plates. The majority of the primary

spines are club shaped with irregularly arranged pustules covering

the sides. They are only one centimeter or two long. These resemble

Balanocidaris Lambert, 1910. Lpnger spines were found which look

like Plegiocidaris Pomel, 1883 and have a long collar. They have a

shaft as long as the collar or two to three times longer. The shaft

is twice the diameter of the collar. Plegiocidaris is found in

Europe from the Norian to the Upper Jurassic. There are also cup

shaped spines like Cyathocidaris in that the aboral side is cup­

shaped or trumpet-shaped.

The echinoids can have a mixture of spines, but it is also possible that

there were two or three different taxa. First, some plates must be

found to assist in the identification.

Material: UNMSM no. 6290, localities UNMSM 004, 005, 006, 007.

Class CRINOIDEA Genus ISOCRINUS von Meyer

Isocrinus californicus Clark, 1915

Isocrinus californicus Clark and Twitchell, 1915, The Mesozoic and Ceno-

zoic Echinodermata of the United States: U.S. Geol. Survey Mon. 54,

p. 21, pi. 1, figs. 2a-c.

Description: Column of medium size, thin pentagonal joints, sharp

reentering angles; crenulated ridges petaloid, each area sharply ter­

minated at its outer extremity. 117

Dimensions: diameter of joint length of joint

Clark's specimens 2 to 5 mm 0.5 to 1 mm lower Luning specimens 4 to 7 mm 0.7 to 1.4 mm

pis cuss ion. m e original description mentions a large canal in the cen—

ter but the illustrations and photographs show what I would call a

small canal, present in the Cinnabar and Dunlap Canyons' crinoids.

The ossicles actually range from pentagonal forms to near circular

forms in a different part of the stem.

Distribution: This species is common in the Triassic of Western North

America. In the Luning of the mound area it is found abundantly in

the former crinoid meadows and also is found in every possible lithol­

ogy or community.

Material: UNMSM no. 6319, locality 004, 005, 006, 007.

Genus Encrinus

(?) Encrinus sp. undet.

Description and Discussion: Small and medium sized round forms are found

in abundance but no ornamentation has been found. These are usually

lumped into a form genus like Encrinus.

Distribution: The ossicles are found in every fossiliferous facies in

the area and probably grew in the crinoid flanking facies.

Material: UNMSM no. 6320, localities 004, 005, 006, 007. 118

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APPENDIX I

Terminology

The word reef has been used so often in so many ways, and even with the recent restriction upon its meaning, a modifier should be used

to clarify the usage (Heckel, 1974). The following reef terms used in

this paper are here defined, so as to avoid confusion.

Carbonate buildups

A body of locally formed (laterally restricted) carbonate sedi­ ment which possesses topographic relief (Wilson, 1975).

Mound

An equidimensional or ellipsoidal buildup.

Patch reef (Wilson, 1975)

Isolated more or less circular area of organic frame-constructed

buildups. In modern seas patch reefs are mainly on shelves and rise into

wave base and close to sea level.

Bioherm

Buildup whose internal composition shows it to be largely

derived from in situ production of organisms or as framework or encrust­

ing growth as opposed to mainly mechanical (hydrodynamical) piling.

Organic framework reef or ecologic reef (Dunham, 1970)

Rigid, wave-resistant topographic structure produced by actively

building and sediment binding organisms.

Stratigraphic reef (Dunham, 1970)

Thick latterally restricted masses of pure or largely pure

carbonate rock, included are carbonate buildups. m

Biostrome (Cumings, 1932)

Distinctly bedded structures that do not swell into lenslike or reef-like form and consist mainly of remains of organisms (Cumings, 1932).

Reef

A buildup that displays (1) evidence of (a) potential wave

resistance or (b) growth in turbulent water which implies wave resistance

and (2) evidence of control over the surrounding environment. PEDX I! APPENDIX

006 Major fossil localities UNMSM R,v Minor fossil localities Tir Pliocene Mammoth rhyodacite ' . Canyons Tes Miocene Esmeralda Formation

^ ---- Lithologic contacts To Miocene andesite breccia ------UNMSM locality contacts Jim Luning Formation-limestone and shale Scale 1.27cm= 8 65 m ]ji8 Luning Formation-argillite and conglomerate Tin Lower member of Luning Formation

Figure 12 General geologic map of Cinnabar and Dunlap Canyons showing locations of UNMSM fossil localities and smaller thesis fossil localities 136

EXPLANATION OP PLATES

Plate 1

1. Pamiroseris norica (Freeh) exterior view, coral has attached

pelecypod, (0.5X) UNMSM 6263.

2. Pamiroseris norica (Freeh), same specimen (IX) UNMSM 6263

3 . Pamiroseris rectilamellosa (Winkler), (IX) UNMSM 6282

Plate 2

1 . Marqarastraea norica (Freeh), internal view of corallites, preserva­

tion of this sort is very rare in Cinnabar and Dunlap Canyons,

(0.8X), UNMSM 6275

2. Same species, exterior view, (IX) , UNMSM 6275

3. Same species, exterior view, (2X) , UNMSM 6275

Plate 3

1. Astrocoenia juvavica (Freeh), exterior view, (IX), UNMSM 6284.

2. Montlivaltia norica Freeh, exterior view, (0.8X), UNMSM 6273.

3. Elyastraea parva (Smith), (IX), UNMSM 6278.

4. Elyastraea profunda (Reuss), (1.1X), UNMSM 6276.

5. Montlivaltia marmorea Freeh, interior cross section, (0.5X),

UNMSM 6272.

Plate 4

1. Entolium sp., one valve, (2X), UNMSM 6250.

2. Cardita sp., interior mold of small specimen, (IX), UNMSM 6263

3. Gryphaea sp., left valve, (1.5X), UNMSM 6302

4. Trichites sp., (0.5X), UNMSM 6259. 137

Plate 4 (cont)

5. Trichites sp., interior mold showing the prominent adductor muscle

scar, (0.5X), UNMSM 6259.

6 . Lima sp., exterior mold, (2X), UNMSM 6268.

Plate 5

1. Trigoniid, exterior mold, (1.5X), UNMSM 6260.

2 . Myophoria sp., exterior mold, (IX), UNMSM 6262.

3. Lopha montiscaprilis (Klipstein), left valve, (2X), UNMSM 6256.

4. Mytilus sp., (0.9X), UNMSM 6252.

5. Chlamys (Chlamys) sp. A, (2.2X), UNMSM 6266.

6. Chlamys (Chlamys) sp. 3, (IX), UNMSM 6265.

Plate 6

1. Terebratula sp., pedicle valve, (3X), UNMSM 6303.

2 . Terebratula sp., pedicle valve, (2X), UNMSM 6303.

3. Terebratula sp., pedicle valve, (2X), UNMSM 6303.

4. Terebratula sp., side view showing prominent beak, (IX), UNMSM 6303.

5. Spiriferina sp., (IX), UNMSM 6308.

6 . Zugmayerella cf. Z. koessenensis, Zugmayer, (1.2X), UNMSM 6312.

7. Spiriferina sp., showing hinge line pedicle beak and open area, (IX),

UNMSM 6308.

8. Spiriferina sp., side view showing beak, (IX), UNMSM 6308.

9. Spiriferina sp., pedicle valve showing width of wing when unbroken,

(IX), UNMSM 6308.

10. Guseriplia bittneri Dagys, side view, (2.5X), UNMSM 6371.

1 1 . Zugmayerella cf. Z. koessenensis Zugmayer, view of open area and

striae (vertical), (IX), UNMSM 6312. Plate 6 (cont)

12. "Pecten" borings, (IX), UNMSM 6321.

Plate 7

1. Juvavites sp., (1.4X), UNMSM 6283.

2. Cidarid spine, side view, (2X), UNMSM 6290.

3. Cidarid spine, view from collar toward top of spine

UNMSM 6290.

4. Polytholsia cylindrica cylindrica, Seilacher, cross section, (IX),

UNMSM 6281.

5. Ascosymplegma expansum Seilacher, cross section, (1.3X), UNMSM 6271.

6. Sponqiomorpha dentriformis Smith, cross section, (0.8X), UNMSM 6279.