Devonian and Mississippian Rocks of the 

Northern Antelope Range, 

Eureka County, Nevada 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182 

Devonian and Mississippian Rocks of the 

Northern Antelope Range, 

Eureka County, Nevada 

By RICHARD K. HOSE, AUGUSTUS K. ARMSTRONG, 

ANITA G. HARRIS, and BERNARD L. MAMET 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182 

A summary of the biostratigraphy of 

Devonian and Mississippian rocks 

and their depositional history 

UN IT ED S TATE S G 0 V E R N MEN T P R INTI N G 0 F F I C E , W A S H IN G T 0 N : 1982 
UNITED STATES DEPARTMENT OF THE INTERIOR 

JAMES G. WATT, Secretary 

GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Library of Congress Cataloging in Publication Data 

Devonian and Mississippian rocks of the northern 

Antelope Range, Eureka County, Nevada 

(Geological Survey Professional Paper 1182) 

Bibliography: p. 17. 

1. Geology, Stratigraphic--Devonian. 2. Geology, 

Stratigraphic--Mississippian. 3. Geology--Nevada--

Antelope Range. 

I. Hose, Richard Kenneth, 1920-

QE665.D44 551.7'4'0979332 

II. Series. 

81-607120 

AACR2 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 
CONTENTS 

Abstract ______________________________________________ _ 

Introduction 

Fossil collections _______________________________________ _ 

Devonian stratigraphy __________________________________ _ 

Beacon Peak Dolomite _______________________________ _ 

Lithology ______________________________________ _ 

Biostratigraphy _________________________________ _ 

Facies and environments of deposition ______________ _ 

McColley Canyon Formation __________________________ _ 

Lithology ______________________________________ _ 

Biostratigraphy _________________________________ _ 

Facies and environments of deposition ______________ _ 

De nay Limestone ___________________________________ _ 

Lithology ______________________________________ _ 

Biostratigraphy _________________________________ _ 

Facies and environments of deposition ______________ _ 

Fenstermaker Wash Formation (new name) _____________ _ 

Lithology ______________________________________ _ 

Page 

1 

1 

1 

1 

1 

4 

5 

5 

5 

5 

6 

8 

8 

8 

8 

9 

9 

9 

Devonian stratigraphy-Continued 

Fenstermaker Wash Formation (new name)-Continued 

Facies and environments of deposition ______________ -

Mississippian stratigraphy ________________ ----------------

Davis Spring Formation (new name) ___________________ _ 

Lithology ________ - - ------------------ ------- ----

Biostratigraphy _________________________________ _ 

Facies and environments of deposition ______________ _ 

Kinkead Spring Limestone (new name) _________________ _ 

Lithology _________________ ----------------------

Biostratigraphy _________________ -----------------

Facies and environments of deposition ______________ _ 

Antelope Range Formation (new name) _________________ _ 

Lithology _______ --------------------------------

Biostratigraphy _________________________________ _ 

Depositional environment ________________________ _ 

Discussion---------------------------------------------

Refurencesciled ----------------------------------------

Page 

10 

10 

10 

10 

11 

11 

12 

12 

12 

13 

14 

14 

14 

15 

15 

17 

Biostratigraphy _________________________________ _ 10 Index ------------ -------------------- 19 

PLATE 

FIGURE 

TABLE 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

ILLUSTRATIONS 

[Plates follow references ] 

McColley Canyon Formation, figs. A-F 

McColley Canyon Formation, figs. A, B; Denay Limestone, figs. C-F 

Denay Limestone, figs. A, B; Fenstermaker Wash Formation, figs. C-F 

Fenstermaker Wash Formation, figs. A-F 

Fenstermaker Wash Formation, figs A-E; McColley Canyon Formation, fig. F 

Davis Spring Formation, fig A; Kinkead Spring Limestone, figs. B-F 

Biostratigraphically significant conodonts from the McColley Canyon Formation and Denay Limestone 

Biostratigraphically significant conodonts from the Fenstermaker Wash and Davis Spring Formations and the Kinkead 

Spring Limestone 

Page 

Index map of central Nevada _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 2 

Geologic map of northern Antelope Range _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 

Generalized Devonian and Mississippian section _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 

Chart showing distribution of biostratigraphically useful conodonts _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 4 

Stratigraphic sections of Devonian formations _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 6 

Stratigraphic sections of Mississippian formations _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 10 

Correlation of the Devonian and Mississippian rocks of the northern Antelope Range with the southern Fish Creek Range and 

theN ewark Mountains ________________________________________________ ·_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 16 

TABLE 

Page 

1. Distribution of foraminifers and algae in the Kinkead Spring Limestone 12 

III 

DEVONIAN AND MISSISSIPPIAN ROCKS 

OF THE NORTHERN ANTELOPE RANGE, 

EUREKA COUNTY, NEVADA 

By RICHARD K. HOSE, AUGUSTUS K. ARMSTRONG, ANITA G. HARRIS, and BERNARD L. MAMET1 

ABS1RACT 

Lower through Upper Devonian rocks of the northern 

Antelope Range, Nev., consist of four formational rank 

units more than 800 m thick, separated from 

Mississippian units by an unconformity. The lower 

three Devonian units, the Beacon Peak Dolomite, 

McColley Canyon Formation, and Denay Limestone are 

known in other areas; the top unit, the Fenstermaker 

Wash Formation, is new. The Mississippian units, more 

than 280 m thick, are divisible into three units which 

are unlike coeval units elsewhere, and are herein 

named the Davis Spring Formation, Kinkead Spring 

Limestone, and Antelope Range Formation. Systematic 

sampling of the Devonian sequence has yielded 

relatively abundant conodonts containing several 

biostratigraphically significant taxa. The Mississippian 

units contain redeposited conodonts of chiefly Late 

Devonian and Early Mississippian (Kinderhookian) age 

together with indigenous Osagean foraminifers and 

algae in the Kinkead Spring Limestone. 

INTRODUCTION 

This paper discusses the stratigraphy, sedimentology, and micropaleontology of the Devonian and Mississippian rocks in the northern Antelope Range of 

central Nevada (fig. 1). This sequence consists of the 

Beacon Peak Dolomite,2 McColley Canyon Formation, 

'University of Montreal. 

2

The Beacon Peak Dolomite, first recognized in the Eureka mining district, was designated 

a member of the lithologically diverse Nevada Formation (Nolan and others, 1956). Because 

the Beacon Peak-and, for that matter, every member of the Nevada Formation-possesses 

all the characteristics of a formation, we here elevate each of its members to formation rank 

and abandon the name Nevada Formation. 

Denay Limestone, and Fenstermaker Wash Formation 

(new name) of Devonian age; and the Davis Spring 

Formation (new name), Kinkead Spring Limestone 

(new name), and Antelope Range Formation (new 

name) of Mississippian age. The distribution of these 

units, and the lines along which stratigraphic sections 

were measured, are shown in figure 2, and a 

generalized stratigraphic section of all the units described herein is shown in figure 3. 

FOSSIL COLLECTIONS 

Conodonts were used to provide a biostratigraphic 

framework for all formations in the area of this report 

because of their well-established zonation in correlative 

rocks elsewhere, particularly in the Devonian and 

Lower Mississippian of the Great Basin (see, for example, Klapper, 1977; Sandberg and Gutschick, 1978; 

Sandberg and Poole, 1977) and because preliminary 

sampling showed them to be very well preserved and 

fairly abundant. Sample sizes ranged from 2 to 4 kg 

and about 80 percent of the samples yielded conodonts. 

Conodont- bearing samples are listed and the distribution of biostratigraphically significant conodont taxa 

are shown in figure 4. The principal biostratigraphic 

indices in the Kinkead Spring Limestone are foraminifers; these were determined at 28 different levels. Conodonts in the three Mississippian formations appear to 

be redeposited. 

DEVONIAN STRATIGRAPHY 

BEACON PEAK DOLOMITE 

The Beacon Peak Dolomite is the oldest Devonian unit 

in the northern Antelope Range. Matti ( 1979) described the unit and its conodonts in some detail, and 
2 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

I 

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0Lone Mountain 

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I 

I 

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FIGURE 1.-Index map of part of central Nevada showing location of northern Antelope Range (hachures). 
DEVONIAN STRATIGRAPHY 3 

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~ Davis 

Spring 

Formation 

MISSISSIPPIAN 

Upper Davis Spring U~ 

II 

Kinkead Spring.-- ;/ 

EXPLANATION 

0 

Fenstermaker 

Wash Formation 

0 

Denay 

Limestone 

McColley 

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Formation 

Beacon 

~ Peak 

Dolomite 

/f 

~}ORDO- Pogonip VICIAN 

Group 

~}CAM- Windfall BRIAN 

Formation 

Contact 

....!.....__ 

Fault-Bar and ball on 

downthrown side. Dotted 

where concealed 

............... Thrust fault-Sawteeth 

on upper plate 

Line ~{~~ured 

section 

FIGURE 2.-Geologic map of northern Antelope Range and location of 

measured sections. 

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FIGURE 3.-Generalized Devonian and Mississippian section of the 

northern Antelope Range. (See figure 5 for explanation of symbois.) 
4 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

as a result we did not study or sample this unit as extensively as our other stratigraphic units. 

LI'TIIOLOGY 

The Beacon Peak Dolomite is remarkable for its consistent lithology both vertically and laterally. It is 

mainly light-gray, finely crystalline dolomite in beds 

1/3 to 1 m thick. The beds are resistant and weather to 

angular blocks but do not form cliffs; rather, owing to 

their uniformity, they generally erode to smoothly 

DEVONIAN 

Lower I Middle 

~ a-E..rt'l ~d' a a: ~OlR"~R"Ol ~Ol ~no 

::r-<=" '<: 

rounded hills and knolls. The almost monotonous 

uniformity of the Bea-con Peak is modified locally by a 

few finely laminated beds which alternate with massive 

structureless dolomite. Conodont- bearing beds of 

brownish- gray medium- grained petroliferous dolomite, 

about one-half meter thick, occur at 65 and 130 m 

below the top of the formation. Locally, thin lenses of 

quartz sandstone are present, as are thin beds of dolomite with abundant floating spheroidal grains of 

frosted quartz. 

) MISSISSIPPIAN SYSTEM 

t Upper I SERIES 

Upper ) Kind~rhook- Osagean OR 

1an STAGE 

co 

f i 0~ a:~ 2!~~~ d' ::ocn-10 ~ g-~ ~ Nl>!!/NZ or-e;;!- -~~1- -~[~[~[--~[- 8~b' !l :"'!ll ~-!!:. 3~ ';'" -:c- OS: enol> 

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Beacon 

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McColley Canyon Peak 

Dolomite Formation 

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Ozarkodina jahnsoni • 

Icriodus huddlei celtibericus ••••••-+• •• ••--•-•-e• 

I. h.? n.subsp. •-•--+• ••---•-e• Pandorinel/ina exigua philipi 

Pandorinel/ina steinhomensis miae 

Polygnathus gronbergi 

Icriodus comiger 

Polygnathus parawebbi 

Tortodus kockelianus subsp. indet. 

Polygnathus linguiformis linguiformis 

Polygnathus trigonicus 

Tortodus kocke/ianus kockelianus 

Polygnathus ct. P. robusticostatus 

Polygnathus ct. P. xylus xylus 

Polygnathus varcus 

Polygnathus decorosus s. I. 

Polygnathus norrisi 

Pandorinellina insita 

Ancyrodelia ct. A buckeyensis 

Icriodus symmetricus 

Palmatolepis ct. P. proversa 

Palmatolepis ct. P. hassi 

Coleodus ? sp. 

lcriodids 

Palmatolepis glabra 

Palmatolepis spp. 

Polygnathus semicostatus 

Bispathodids 

Pseudopolygnathids 

Polygnathus communis 

Siphonodella duplicata 

Siphonodel/a isostichia 

Gnathodus punctatus 

• 

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Limestone 

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FIGURE 4.-Chart showing distribution of biostratigraphically useful conodonts. 

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9 
DEVONIAN STRATIGRAPHY 5 

BIOSTRATIGRAPHY 

The Beacon Peak Dolomite is lithologically identical 

to and coextensive with the Sevy Dolomite of eastern 

Nevada and western Utah. The basal meter of the Sevy 

Dolomite of western Utah has yielded a diverse marine 

fauna, including Paleocyclus identified by W. Oliver 

(written commun., 1961). Conodonts have also been 

obtained from about 30 and 34 m above the base of the 

Sevy in the Kings Canyon area of the Confusion Range 

(Matti, 1978), and gastropods from about 60 m above 

the base. Osmond ( 1954) reported the coral Halysites 

from the lower Sevy of the Egan Range, Nev. Osmond 

( 1962) attributes to J. G. Johnson identification of 

Late Silurian marine fossils from the Sevy of the 

Pahranagat Range. Although such occurrences are 

unusual, they indicate either a marine origin for at 

least parts of the Beacon Peak and Sevy or that marine 

faunas were transported from nearby in tidal channels. 

Two brownish-gray dolomite beds at 65 and 130 m 

below the top of the Beacon Peak Dolomite were 

sampled for conodonts. The lower sample yielded 

representatives of Pseudoneotodus beckmanni (Bischoff 

and Sannemann) and Ozarkodina remscheidensis? 

Ziegler, the latter indicating an age range of very latest 

Silurian to Early Devonian (into the Ozarkodina n. sp. 

D Zone of Klapper, 1977). The upper sample (USGS 

colin. 9657-SD, fig. 4) yielded abundant 

representatives of Ozarkodina aff. 0. johnsoni Klapper 

indicating the Ozarkodina n. sp. D Zone or Pedavis 

pesavis Zone of the Lower Devonian. 

FACIES AND ENVIRONMENTS OF DEPOSITION 

Osmond ( 1962) interpreted the Beacon Peak-Sevy 

depositional site to have been shallow ponds and mud 

flats, the sediment being derived from an upland of 

Cambrian and Ordovician carbonate rocks to the east. 

He interpreted the laminations as the result of filling of 

shallow depressions within the mud flats, but did not 

specify whether the provenance carbonate was dolomite or limestone. 

In fact, the Beacon Peak-Sevy depositional environment was more comparable to that of western Andros 

Island in the Bahamas, where dolomite is forming 

today in supratidal flats. In the Bahamas, as Folk and 

Land ( 1975) point out, gypsum is not accumulating in 

the supratidal flats owing to the higher rainfall and 

lower rates of evaporation, and they suggest that the 

dolomite may form from dilution of normal ~eawater by 

wet-season,rain water. 

Stable isotope analyses of two specimens from the 

Beacon Peak are as follows: 

Sample 

Ar-1 

Ar-2 

180 (SMOW) 

+25.60° I oo 

+25.02° I oo 

13C (PDB) 

-o.ooo2° I oo 

+0.13° I oo 

Yield C02 

90 percent 

89 percent 

These values indicate that the carbonate formed in 

marine waters. 

McCOLLEY CANYON FORMATION 

In the Sulphur Springs Range, Carlisle, Murphy, Nelson, and Winterer ( 1957) named the sequence of 

limestone above the Lone Mountain Dolomite and beneath a quartzite sequence, the McColley Canyon 

Member of the Nevada Formation. Johnson later 

( 1962) elevated the McColley Canyon to formation 

rank. In the northern Fish Creek Range, an equivalent 

but thinner unit above the Beacon Peak Dolomite and 

below a sandstone unit was called the Grays Canyon 

Limestone Member of the Nevada Formation by Nolan 

and others ( 1974). In the northern Antelope Range we 

follow Johnson's ( 1962) usage for the McColley Canyon Formation where it rests on the Beacon Peak Dolomite but is not overlain by sandstone. 

LITHOLOGY 

The McColley Canyon Formation is about 200m thick 

and forms slopes that are broken here and there by 

thin ledges (fig. 5). It is composed of nearly all lime· 

stone except the lower 10 m, which is light-brownishgray, fine· grained, organic detrital and fossiliferous 

dolomite. The basal one-half meter of this dolomite 

contains floating quartz sand grains almost certainly 

reworked from the underlying Beacon Peak Dolomite. 

Most of the remaining rock is light-yellowish-gray to 

brownish- gray platy argillaceous limestone, mainly 

wackestone with minor packstone and dolomitic pelletal packstone. Calcareous shale is common 10 to 15 m 

above the base of the formation. The wackestone con· 

tains pellets of indeterminate origin and comminuted 

echinoderm and brachiopod debris. Both packstone 

and wackestone have the same kinds of clasts. 

The upper 19 m of the McColley Canyon is an 

encrinite or crinoidal packstone, containing abundant 

distinctive crinoid columnals with double n axial" 

canals. Similar crinoidal limestone is present at Lone 

Mountain, 48 km to the north, in Merriam's ( 1973) 

Nevada Formation unit 3. The encrinite, which forms a 

resistant rounded bench, has a sharp contact with the 

wackestone. Transmission and scanning electron 

micrographs of specimens are shown in plate 1. 

Insoluble residues from the McColley Canyon contain 

abundant sponge spicules (pl. 2, fig. B), and subrounded to rounded quartz grains (pl. 5, fig. F) in the 

400- to 500-J.Lm size range. Quartz, which makes up 

1-5 percent of the unit, appears uniformly distributed 

throughout. 

The contact between the McColley Canyon Formation 

and the underlying Beacon Peak Dolomite is characterized by light- gray dense dolomite below and lightolive· gray medium- grained dolomite directly above 
6 

9647-SD 

9988-SD 

9972-SD 

9648-SD 

9646-SD 

DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

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FIGURE 5.-Stratigraphic section of Devonian formations of northern Antelope Range showing lithology and microfossil 

collections. 
DEVONIAN STRATIGRAPHY 7 

that gives way higher in the section to micrite and then 

to packstone. The McColley Canyon Formation forms 

slopes with scattered ledges in contrast to the ledgeforming Beacon Peak. 

BIOS1RATIGRAPHY 

dicates that the lower 63 m of the McColley Canyon is 

probably no older than the Eognathodus sulcatus sulcatus Zone but could be as young as the Polygnathus 

dehiscens Zone based on the co-occurrence of I. h. celtibericus with indices of the E. sulcatus sulcatus and E. 

sulcatus n. subsp. in other sections of the lower McColTen samples from the McColley Canyon yielded ley Canyon Formation in central Nevada (Klapper, 

conodonts (pl. 7, fig. 5). All samples contain an 1977, figs. 3, 5) and with P. dehiscens in succeeding 

icriodid-panderodid-pseudoneotodid biofacies, collections in our section. Additional information on the 

characteristic of warm, shallow water, of which 90-95 lower age limit of the McColley Canyon comes from a 

percent are species of Icriodus (see Weddige and conodont collection 60 m below the top of the underlyZiegler, 1976). Only samples from 115 m above the ing Beacon Peak Dolomite (USGS colin. 9657 -SD) 

base of the formation and higher contain where it is contiguous with our measured section. The 

representatives of Pandorinellina and (or) Polygnathus. only conodonts in this collection are representatives of 

Ichthyoliths are rare to common in all ten samples. Ozarkodina aff. 0. johnsoni Klapper, which indicates 

The base of the McColley Canyon Formation contains the Ozarkodina n. sp. D zone or Pedavis pesavis Zone. 

abundant icriodids, most of which conform to the de- The Early Devonian age of this collection and the thickscription of Icriodus huddlei celtibericus Carls and ness of undated strata between it and the base of the 

Gandl ( 1969) (pl. 7, figs 1-3, 8, 9) and are the same as McColley Canyon is compatible with our Early Devol. h. curvicauda of Klapper ( 1977) (Gilbert Klapper, nian age determination for the lower McColley Canyon. 

oral commun., 1979). Within the icriodid population, The next collection, from 115 m above the base of 

however, there are several large icriodontan elements the McColley Canyon, contains the same abundant icthat are wider and have better developed spurs along riodids and, significantly, a few representatives of 

the inner posterior margin than typical specimens of I. Pandorinellina exigua philipi (Klapper) (pl. 7, figs. 10, 

h. celtibericus; these are designated I. h.? n. subsp. (pl. 11) and one specimen of Polygnathus dehiscens Philip 

7, figs. 4, 5). In addition to icriodids, the lower part of and Jackson. This sample is indicative of the P. dehisthe McColley Canyon contains a few representatives of cens Zone of Klapper ( 1977). A sample from 142 m 

Ozarkodina excavata (Branson and Mehl), panderodids, above the base of the formation contains specimens of 

and pseudoneotodids. These, with the exception of 0. Pandorinellina steinhornensis miae (Bultynck) and 

excavata, are the only conodonts in the samples from Polygnathus gronbergi, both of which also occur at 153 

the lower 63 m of the formation, and of these, only I. h. m above the base of the formation together with speciceltibericus is of biostratigraphic value. Its presence in- mens that represent a form transitional between P. deEXPLANATION 

COMPOSITION, IN PERCENT 

0 1 0 50 90 1 00 Dolomite 

1:1 k~L~L~L~~~~a~a 1 00 90 Dolomitic 50 Calcitic 10 0 Limestone 

Limestone limestone dolomite Dolomite 

,._._-_._, 

Nodular 

chert 

IJJ8BI 

Carbonate 

lithoclast 

TEXTURE 

~~ ~ ~I Chert in 

limestone 

and dolomite 

I~CD~I Nodular limestone 

in shale 

M - Lime mudstone 

W- Wackestone 

P -Packstone 

G -Grainstone 

D -Dolomite 

FIGURE 5.-Continued 

CARBONATE PARTICLES 

OTHER THAN FOSSILS 

Coated particles 

Size mm Mud One layer More than 

~O.d63_L one layer 

-B- 0 

Sand ~.0 cp Superficial Ooid 

Granule 0 ([) ooid @ 

Pebble 'j <II> P'tsoid 

SYMBOLS FOR FOSSIL PARTICLES 

-p:ll 

Calcareous algae 

>- Sponge spicules 

a, 

Smaller foraminifers 

Echinoderm * ~ 

Calcispheres 

CD 

Corals 

T 

Bryozoans 

't7 

Brachiopods 

Gl 

Ostracodes 
8 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

hiscens and P. gronbergi. Both samples also contain I criodus heddlei celtibericus together with a late form of 

I. h.? n. subsp. that has developed a bilatericresid outline (a well-developed anteriorly projecting inner posterior spur; pl. 7, figs 6 and 7). This interval is assigned 

to the P. gronbergi Zone and may even belong in the 

lower part of this zone where P. gronbergi, P. dehiscens, 

and P. s. miae are known to occur together (Klapper, 

1977' fig. 3). 

The highest sample from the McColley Canyon, from 

183 m above its base, contains chiefly representatives 

of Icriodus corniger Wittekindt (pl. 7, figs. 16, 17) as 

well as a few polygnathid fragments that are indeterminate at the species level. The icriodids indicate a 

post-Polygnathus gronbergi, pre-Tortodus kockelianus 

kockelianus age; this interval encompasses the LowerMiddle Devonian transition. Thus, the McColley Canyon Formation in the northern Antelope is of late Early 

Devonian age and may extend slightly into the Middle 

Devonian. Klapper ( 1977) reported that the top of the 

McColley Canyon Formation at Lone Mountain lies 

within the Polygnathus serotinus Zone and is of Early 

Devonian age. 

FACIES AND ENVIRONMENT OF DEPOSITION 

The McColley Canyon Formation in the northern Antelope Range contains abundant well-preserved tabulate corals and some rugose corals in addition to abundant brachiopods. These assemblages suggest warm 

shallow marine depositional areas, perhaps sheltered 

lagoons with free access to marine waters and scattered 

patch reefs. The accumulation of lime mud precludes 

strongly agitated waters. 

In 1977, Gilbert Klapper established a Lower Devonian and a preliminary Middle Devonian conodont zonation in central Nevada in limestone ( including the 

type section of the McColley Canyon Formation) that 

were interpreted to have formed in continental slopeouter shelf and continental-shelf environments. The 

northern Antelope Range section lies just east of the 

sections studied by Klapper, and at least the Lower Devonian part (McColley Canyon Formation) formed 

nearer shore and contains less varied and fewer biostratigraphically useful conodonts than those parts 

studied by Klapper. 

DENA Y LIMESTONE 

The Denay Limestone was named for the Denay Valley, which separates the northern Simpson Park Mountains from the northern Roberts Mountains. As originally defined by Johnson ( 1966) on the east flank of 

Willow Creek Canyon in the northern Roberts Mountains, the Denay rests on the McColley Canyon Formation and is overlain by the Devils Gate Limestone. We 

use the term in the northern Antelope Range for a 

sequence directly above the McColley Canyon and 

lithologically the same as the type Denay. In the northern Antelope Range, however, the Denay is overlain by 

the Fenstermaker Wash Formation rather than the Devils Gate Limestone. 

LI1HOLOGY 

The De nay Limestone of the northern Antelope Range 

is 260 m thick and is predominantly argillaceous lime 

mudstone with a little wackestone and less packstone 

(fig. 5). Characteristically, the sequence is topographically recessive but it forms several massive benches 

5-10 m thick. Beds range from 5 to 30 em in thickness, 

the bedding surfaces being defined by laminae about 1 

mm thick. In most exposures the limestone is even 

bedded and nonbioturbated. Most beds are 2.5-15 em 

thick. The De nay is mainly gray to light olive gray, but 

brownish-gray tones are common. Tentaculites (Nowakia sp. and Striatolina sp.) are present on bedding surfaces in the lower 120 m and constitute a distinctive 

element of the formation (pl. 2, figs. C, D). 

Thin-section and scanning electron microscope 

analyses show that the formation is carbonaceousargillaceous-dolomitic lime mudstone to wackestone. 

Dolomite rhombs 10-30 ,urn in size are present in the 

micrite matrix, and clay minerals are present between 

the calcite crystals (pl. 2, figs. D, E, F). 

Echinoderm-peloid packstones and grainstones also 

occur within the Denay. The peloids contain isolated 

rhombs of dolomite in a lime mudstone matrix (pl. 3, 

figs. A, B). Flat limestone pebbles as much as 15 em 

long form a conglomerate 127-140 m above the base of 

the formation. The matrix of the conglomerate is quartz 

sand, broken corals, and bryozoans. The conglomerate 

is overlain by 1 m of crossbedded echinoderm 

packstone. Several beds in the sequence contain 

brachiopods. 

The contact of the Denay and the upper crinoidal 

limestone of the underlying McColley Canyon Formation is topographically distinct. The recessive Denay 

forms a gentle slope above the rounded ledge of the 

McColley Canyon. 

BIOSTRATIGRAPHY 

Six samples of the Denay Limestone yielded conodonts, but only four contained biostratigraphically useful taxa. The Denay contains a polygnathid- belodellidpanderodid biofacies composed of 90-95 percent 

Polygnathus, 95 percent of which is P. parawebbi Chatterton. Ichthyoliths are less common than in the McColley Canyon Formation. The Denay also contains conodont pearls in almost every sample yielding conodonts 

(pl. 7, fig. 18). These dimpled lamellar apatite spheres 
DEVONIAN STRATIGRAPHY 9 

are also prevalent in our other conodont collections 

from Middle and lower Upper Devonian rocks in central 

Nevada. Apatite spheres associated with conodonts 

have been reported from Cambrian through Carboniferous rocks; Glenister, Klapper, and Chauff 

( 1976) were the first to suggest that these are pearls 

secreted by the conodont- bearing animal. 

The entire Denay appears to be of Middle Devonian 

age, even though the lower 92 m of the formation in 

the northern Antelope Range has not yet produced 

biostratigraphically diagnostic conodonts. The base of 

the Denay at its type section in the northern Roberts 

Mountains, however, has yielded lowermost Middle Devonian conodonts of the Polygnathus costatus costatus 

Zone (Klapper, 1977, fig. 5). Our lowest sample containing diagnostic conodonts is from 92 m above the 

base of the formation and contains Polygnathus 

parawebbi Chatterton. This sample is probably no older 

than the base of the Tortodus kockelianus australis Zone 

(P. parawebbi has thus far not been found below the T. 

k. australis Zone in central Nevada; Klapper, 1977) and 

no younger than the Tortodus kockelianus kockelianus 

Zone, because stratigraphically higher collections contain representatives ofT. k. kockelianus. 

A sample from 125 m above the base of the formation 

contains abundant representatives of Polygnathus 

parawebbi (pl. 7, fig. 21) and one specimen each of P. 

trigonicus Bischoff and Ziegler (pl. 7, fig 19), T. kockelianus subsp. indet., and P. linguiformis linguiformis 

Hinde morphotype indet. This collection is characteristic of the australis and T. k. kockelianus Zones. The T. k. 

kockelianus Zone is represented in collections from 134 

and 164 m above the base of the formation. The lower 

collection contains only T. kockelianus kockelianus Bischoff and Ziegler, Polygnathus parawebbi, and panderodids. The upper collection, which is also our highest collection from the Denay, contains abundant P. 

parawebbi (pl. 7, fig 20) and belodellids as well as several specimens ofT. k. kockelianus (pl. 7, figs. 22, 23), 

Polygnathus trigonicus, and P. cf. P. robusticostatus 

Bischoff and Ziegler. We have no other conodont collections from the remaining 6 7 m of the formation. Collections from the lower 5 m of the overlying Fenstermaker Wash Formation, however, are also of Middle 

Devonian age and contain conodonts of the lower subzone of the Polygnathus varcus Zone. 

FACIES AND ENVIRONMENTS OF DEPOSITION 

The principal faunal elements of the Denay Lime -

stone ·,are pelagic forms: conodonts and, in the lower 

half, Nowakia sp., Striatolina sp., and sparse radiolarians. It seems that surface waters were normal marine 

but the bottom waters were generally euxinic. 

The argillaceous lime mudstone accumulated in a 

marine environment of low wave energy, well below 

wave base. The presence of laminations suggests hostile bottom conditions that inhibited bioturbation. Occasionally, however, during the accumulation of the 

Denay, bottom conditions became more favorable for a 

restricted benthic fauna as indicated by a few thin beds 

containing brachiopods. A conglomerate containing 

broken corals, bryozoans, and quartz sand may have 

been a debris flow from the shelf-slope boundary area 

to the east. 

Part of the Denay is the lithic correlative of the 

Woodpecker Limestone of the Newark MountainAlhambra Hills area; such a relation requires a similar 

depositional habitat. The area of the southern Diamond 

Mountains was a shallow sea during the deposition of 

the Sentinel Mountain Dolomite, deeper during deposition of the Woodpecker Limestone, and shallow again 

to produce the Bay State Dolomite. 

FENSTERMAKER WASH FORMATION 

Conformably overlying the Denay Limestone in the 

northern Antelope Range is a sequence of rock here 

named the Fenstermaker Wash Formation (fig. 5). We 

have subdivided it into a lower part, 80-183 m thick, a 

middle part 42 m thick, and an upper part 60 m thick. 

The variation in thickness of the lower part is probably 

a result of undetected faulting, most likely in the more 

northern section (fig. 2). The lower part was measured 

in the SE1/4 sec. 16, T. 16 N., R. 51 E., and 

NE1/4NE1/4 sec. 21, T. 15 N., R. 51 E.; a second inner 

section of the lower part (the thinner one) was measured in the NE1/4NE1/4 sec. 20, T. 15 N., R. 51 E. 

The middle and upper parts were measured in the 

NE1/4 sec. 20 and NW1/4 sec. 21, T. 15 N., R. 51 E 

(see fig. 2). The formation derives its name from 

Fenstermaker Wash, located northeast and east of the 

northern part of the Antelope Range. 

LITIIOLOGY 

The lower part is made up principally of mediumgray to light-brownish-gray, massive, medium- to 

coarse- grained, peloid -echinoderm- coral, stromatoporoid-brachiopod packstone and wackestone (pl. 3, 

figs. C, D). Dolomite of coarse texture is common 100 

to 124m above the base of the formation (pl. 3, figs. E, 

D; pl. 4, figs. A-F). Yellowish platy silty fine-grained 

limestone that forms slopes is present from 124 to 160 

m above the base. The lower unit contains corals, 

brachiopods, crinoid columnals, and Receptaculites 

more than 1 em thick and as much as 20 em across. 

The middle part is mainly pale-yellowish-orange 

siliceous laminated siltstone and claystone. It includes 

some thin beds of wackestone to packstone, which contain sparse fish remains. This unit generally forms 

slopes that are poorly exposed. 
10 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

The upper part of the formation is medium- gray 

crossbedded peloid-mudlump packstone to grainstone. 

Calcispheres and ostracodes are present. About 40 percent of the rock is medium-sized subequant wellrounded quartz that occurs as floating grains in lenses 

and stringers. This topmost unit forms a massive and 

prominent cliff. 

The contact of the Fenstermaker Wash Formation 

with the underlying De nay is sharp. Medium-gray to 

medium-dark-gray even-bedded lime mudstone below 

is succeeded by light-yellowish- gray medium- to 

coarse- grained packstone that forms cliffs. 

BIOSTRATIGRAPHY 

Nine of eleven collections from the Fenstermaker 

Wash Formation have biostratigraphically useful taxa. 

The formation is of Middle and Late Devonian age and 

contains a polygnathid- belodellid- panderodid biofacies 

including at least 90 percent Polygnathus in its Middle 

Devonian part and a polygnathid-palmatolepid-icriodid 

biofacies including 90 percent Polygnathus in its Upper 

Devonian part. Conodont~~ pearls" are abundant to rare 

in most samples; ichthyoliths are present but rare. 

The lower 70 m of the formation is no younger than 

the lower Polygnathus varcus Subzone of the P. varcus 

Zone based on the co-occurrence of Polygnathus varcus 

Stauffer (pl. 8, fig. 3) andP. parawebbi (pl. 8, figs. 1, 

2). P. varcus first occurs and P. parawebbi last occurs 

in the lower P. varcus Subzone (Ziegler and others, 

1976). Representatives of P. parawebbi are the most 

abundant conodonts in this part of the formation, just 

as they are in the underlying Denay Limestone. 

We have no conodonts from the overlying 100m and 

only a few indeterminate bar and platform fragments in 

a collection from 170 m above the base of the formation. A collection at 187 m above the base contains 

conodont species whose ranges cross what is commonly 

considered to be the Middle-Upper Devonian boundary 

(the boundary between the lowermost and lower 

Polygnathus asymmetricus Subzones). These include 

abundant representatives of Polygnathus decorosus s. l. 

(Ziegler, 1966) and several specimens of Polygnathus 

norrisi Uyeno (pl. 8, fig. 6) and Pandorinellina insita 

(Stauffer) (pl. 8, fig. 7). Of these, P. norrisi appears to 

be restricted to the lowermost and lower P. asymmetricus Subzones; the collection is assigned to this interval. P. decorosus s. l. (pl. 8, figs. 4, 5) continues to be 

the most abundant species at 193 m above the base of 

the formation, where it occurs with several specimens 

of Icriodus symmetric us Branson and Mehl (pl. 8, figs. 

8, 9), one juvenile and several incomplete adult specimens of Palmatolepis cf. P. proversa Ziegler (pl. 8, fig. 

11) and one juvenile specimen of Ancyrodella cf. A. 

buckeyensis Stauffer (pl. 8, fig. 10). This collection is 

no older than the middle P. asymmetricus Subzone and 

probably no younger than the lower Palmatolepis gigas 

Subzone. P. decorosus s. l. and a few juvenile and 

fragmentary palmatolepids occur at 230 m above the 

base of the formation, and only incomplete palmatolepids that compare well with Palmatolepis hassi 

Muller and Muller (pl. 8, fig. 12) occur in a collection 

at 260-270 m above the base of the formation. Our 

highest sample is from the upper meter of the formation (USGS colin. 10014-SD) and was collected and 

processed after the fossil plates had been prepared. 

This 6-kg sample yielded representatives of Ancyrodella 

buckeyensis Stauffer and Palmatolepis gigas Miller and 

Youngquist as well as other less diagnostic conodonts. 

The overlapping ranges of these two species indicate 

that the lower or upper P. gigas Subzone (Frasnian) is 

represented at the top of the Fenstermaker Wash Formation in our measured section. 

FACIES AND ENVIRONMENTS OF DEPOSITION 

The lower unit of the Fenstermaker Wash Formation 

contains a fauna suggestive of warm intertidal to subtidal marine deposition. The environment was also one 

of proximity to strong wave and current action, for the 

sequence is largely calcarenite whose clasts are derived 

from marine invertebrates. Parts of the lower unit may 

well be debris flows. 

The middle unit of laminated siltstone and claystone 

suggests a deeper water environment and a high influx 

of fine-textured terrigenous silt and clay. A few 

coarse-textured wackestone to packstone beds may be 

debris flows. The top unit contains calcispheres, peloidal mudlump packstone to grainstone, and a large admixture of quartz grains. It is crossbedded in part and 

probably represents a shallow, shoaling subtidal depositional site. 

MISSISSIPPIAN STRATIGRAPHY 

DAVIS SPRING FORMATION (NEW NAME) 

The name Davis Spring Formation is applied to a 

125-m-thick sequence of slope-forming rock above the 

Fenstermaker Wash Formation in the SE1 I 4 sec. 20, T. 

16 N., R. 51 E. This sequence is considered its type section. The name is derived from Upper Davis Spring, 

about 3 km southeast of the measured section (fig 2). 

LITHOLOGY 

The Davis Spring Formation is very fine grained 

pale- brown siliceous dolomitic siltstone and finely 

laminated chert (fig. 6). The upper 15 m or so of the 

formation is slightly more siliceous than the rest of the 

unit, but the proportion of silica throughout is significant. Quartz is present as silt-size grains and as what 

appears in some thin sections to be cement or secon-
MISSISSIPPIAN STRATIGRAPHY 11 

dary partial replacement. A translucent pale- brown 

pigment, presumably organic, is present at some 

levels. In some zones small clusters of hematite are 

present, and some is secondary after pyrite. The only 

fossils found in thin sections are sparse radiolarians 

(pl. 6, fig. A) although conodonts were obtained 18 m 

above the base of the formation. 

M1351 

M1350 

M1349 

M1348 

M1347 

M1346 

M1345 

M1344 

M1343 

M1342 

M1341 

M1340 

M1339 

M1338 

M1337 

M1336 

M1335 

M1334 

M1333 

M1332 

M1331 

M1330 

8/9 

8/9 

8 

G 

'#. 

7 

Ill 

c: 

·a; 

c, 

"0 

c: 

ca 

Ill 

ti 

C" 

E 

E 

M 

c:i 

p 

FIGURE 6.-Stratigraphic section of Mississippian formations of 

northern Antelope Range showing lithology and microfossil collections. (See figure 5 for explanation of symbols.) 

Dolomite is present mainly as very fine irregularly 

shaped grains in the silt size range, but rhombs are not 

uncommon. A small amount of illite is present in nine 

samples from various levels throughout the formation. 

Kaolinite in very small quantities is present in a few 

samples. Fine laminations are clearly visible in thin sections from each of about ten different levels in the 

sequence. The unit is finely laminated throughout and 

is not bioturbated. 

The contact with the underlying Fenstermaker Wash 

Formation is very sharp. Beds below the contact form a 

resistant massive limestone cliff; those above form 

slopes. The topmost one meter of the underlying 

Fenstermaker Wash Formation contains conodonts no 

younger than upper P. gigas Subzone and the contact 

therefore represents an unconformity of considerable 

magnitude. 

BIOSTRATIGRAPHY 

Our only conodont collection from the Davis Spring 

Formation is from 20 m above its base. The collection 

contains hundreds of conodont fragments as well as 

many complete to nearly complete specimens, most of 

which have numerous fractures. The conodonts are representative of Devonian and Mississippian species, and 

most if not all of them are redeposited. Late Devonian 

forms are more abundant than Mississippian forms. 

The Devonian elements, chiefly of Famennian age, are 

palmatolepids, mainly Palmatolepis glabra Ulrich and 

Bassler (pl. 8, fig. 13), and Polygnathus semicostatus 

Branson and Mehl (pl. 8, fig. 16), and icriodids. The 

Mississippian elements are Gnathodus delicatus Branson and Mehl, G. punctatus (Cooper) (pl. 8, fig. 15), 

and Siphonodella isosticha (Cooper). The collection also 

contains several specimens of Polygnathus communis 

Branson and Mehl and one bispathodid; these could be 

components of the Devonian fauna, the Mississippian 

fauna, or possibly both faunas. The youngest conodonts 

in the collection are chiefly of late Kinderhookian age, 

although G. punctatus and P. communis can range into 

the Osagean. Thus, the Davis Spring Formation is no 

older than late Kinderhookian but might be of Osagean 

age because even the youngest conodonts could be redeposited. The overlying Kinkead Spring Limestone is 

of middle? to late Osagean age. 

FACIES AND ENVIRONMENTS OF DEPOSITION 

The Davis Spring Formation is finely laminated 

siliceous dolomite with organic pigment in the matrix. 

The unit appears not to be bioturbated and has yielded 

conodonts, some of which were redeposited from Devonian strata, and radiolarians. The abundance of organic material, paucity of benthic fossils, and lack of 

bioturbation suggest euxinic bottom waters and oxy-
12 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

genated upper levels of marine waters that supported a . 

limited pelagic fauna. The sediment accumulated below 

wave base. The dolomite may have resulted from 

hypersalinity of the water close to the bottom; however, no features normally associated with hypersaline 

deposits were found. 

KINKEAD SPRING LIMESTONE (NEW NAME) 

The name Kinkead Spring Limestone is herein 

applied to more than 160 m of limestone and associated 

rock that overlies the Davis Spring Formation in its 

type section measured in SEl I 4 sec. 20 and SWl I 4 

sec. 21, T. 16 N., R. 51 E (fig. 1). The name is derived 

from Kinkead Spring, about 4 km southeast of the 

measured section. 

The thickness of the Kinkead Spring Limestone cited 

above is a minimum amount as the upper part of the 

formation is here a thrust fault (fig. 6). Furthermore, 

there is a 20- to 30-m covered zone just under the 

thrust in which scattered outcrops and float, which are 

mixed with float from the overlying Cambrian rocks, 

suggest that Kinkead lithology persists through more 

than 220 m. The upper 60 m or so was collected for 

microfossils about 2 km southwest of the map area just 

north of Ninemile Canyon. 

LITIIOLOGY 

The formation is composed mainly of packstone to 

grainstone and minor wackestone and micrite (pl. 6, 

figs. B-F). The clasts are made up of peloids, ooids, 

skeletal fragments, foraminifers, algae, and, at some 

levels, scattered silt-sized quartz grains. Sparse lithoclasts, apparently derived from the Davis Spring Formation, occur 50 m above the base. Most of the clasts 

range in size from medium to coarse. Colors are mainly 

medium gray to gray, but some light-olive- gray to 

yellowish-gray zones are present. Most of the sequence 

is thin bedded or even platy, but several beds 112 to 1 

m thick form ledges. 

The contact of the Kinkead Spring Limestone with 

the underlying Davis Spring Formation is sharp; beds 

below are pale-brown to reddish-brown slope-forming 

platy siliceous dolomite, whereas those above are gray 

medium- to coarse- grained more resistant limestone. 

BIOSTRATIGRAPHY 

Three conodont collections from the Kinkead Spring 

Limestone are from the lower 30 m. They contain the 

TABLE !.-Distribution of foraminifers and 

USGS locality number M1324 M1325 M1326 M1327 M1328 M1329 M1330 M1331 M1332 M1333 M1334 

Height above base (in meters) 

14 23 25 26 28 43 44 46 48 51 

X 

X X X X 

X X 

X 

X X X 

X 

X 

X X X X 

X 

X 

X 

X 

X X X 

X X 

X 

X 

X X X X 

X X X 

X X X X 

X 

X X X X 

X X X 

X 

Tuberendothyra sp. 

Tuberendothyra tub;;c~l~ta- -(Ch~;;;sh~~;~- ~ ~~ ~ ~ ~ ~ ~~ ~ ~ ~~ ~ ~ ~~ ~ ~ Septatournayella sp. _ X 

~.~~~:~~i~;:.?~hr~ ~~~~ ~ ~ ~~ ~ ~~~~~ ~ ~ ~~ ~ ~~~ ~ ~ ~=~ ~~ ~ ~ ~~~ ~~~~~ ~~ Brunsiina sp. X X 

Glomospiranefi~ sp~ ~~= = ==== == == = = == == ==== == == == == == == == == == 
MISSISSIPPIAN STRATIGRAPHY 13 

same abundant mixed fauna of Late Devonian and 

Early Mississippian (Kinderhookian) species described 

from the underlying Davis Spring Formation. The Kinkead Spring, however, contains foraminifers of Osagean age; representatives of Mamet's Zone 8 occur in 

its lower 80 m, and species that range across the 8-9 

zonal boundary are present from 125 m to about 190 m 

above its base (table 1). The foraminifers are interpreted as indicating that the Kinkead Spring was deposited in Osagean time. The foraminifers also suggest 

that all the conodonts in our collections from the Kinkead Spring were redeposited, with the possible exception of Gnathodus punctatus and Polygnathus commums. 

The collections contain more Devonian than Mississippian specimens; all contain palmatolepids, dominantly Palmatolepis glabra, Gnathodus delicatus (pl. 8, 

fig. 22), Gnathodus punctatus, Gnathodus delicatus (pl. 

8, fig. 19), and Siphonodella isosticha. In addition to 

these, the following fossils have also been noted: bispathodids, a Middle Ordovician Coleodus? sp. (pl. 8, 

fig. 17), characteristic of the lower Middle Ordovician 

in part of the Antelope Valley Limestone in central 

Nevada, and conodont ((pearls" at 5 m abgve the base 

of the formation; Polygnathus semicostatus, 

Siphonodella duplicata (Branson and Mehl), and 

pseudopolygnathids at 25 m above the base; and S. 

algae in the Kinkead Spring Limestone 

duplicata (pl. 8, fig. 21) and icriodids (pl. 8, fig. 18) at 

30m above the base. 

The reworked conodonts in the Davis Spring and Kinkead Spring Formations indicate that chiefly Famennian (latest Devonian) and Kinderhookian (Early Mississippian) deposits were being eroded during the deposition of these formations and that even lower Middle 

Ordovician rocks were then exposed to erosion. 

The microfossils within the Kinkead Spring Limestone are Tournaisian (Osagean) Zone 8 in age in the 

lower 70 m. The upper 70-80 m of limestone are zone 

8 /9 transition. The upper Tournaisian, zone 8, is 

characterized by Tuberendothyra tuberculata ( Chernysheva) while Septebrunsiina and Rectoseptaglomospiranella are progressively eliminated. The acme of 

Spinoendothyra accompanied by spinose tournayellids 

is characteristic of zone 9. The microfossil assemblage 

of the Kinkead Spring Limestone of the Antelope 

Range is widespread in the Cordillera of North 

America, occurring in the Wachsmuth Limestone of the 

central Brooks Range, Alaska (Armstrong and Mamet, 

1977), Shunda Formation of the Canadian Rocky 

Mountains (Mamet, 1976; Bamber and Mamet, 1978), 

the lower part of the Mission Canyon Limestone of 

Montana and western Wyoming, the Madison Limestone of central Wyoming (Sando and others, 1969), 

the Thunder Springs Member of the Redwall Limestone 

M1335 M1336 M1337 M1338 M1339 M1340 M1341 M1342 M1343 M1344 M1345 M1346 M1347 M1348 M1349 M1350 M1351 

Height above base (in meters) 

53 54 57 58 60 61 67 83 123 158 

X X 

X X X X X 

X 

X 

X X 

X X 

X X 

X X 

X 

X X X 

X X 

X X X 

X 

X X X X 

X X X 

X X X 

X 

X X 

X X 

X X 

X X 

X 

X 

159 165 170 

X X 

X 

X 

X X 

X 

X 

X 

X 

X 

X 

X 

175 180 

X X 

X 

X 

X X 

X 

X 

X 

185 

X 

X 

X 

X 

190 

X 

X 

X 

X 

X 

X 

X 

X 
14 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

in Arizona (Skipp, 1969), the Esc a bros a Limestone of 

southeastern Arizona (Armstrong and Mamet, 1978), 

and the Dawn and part of the Anchor Limestone 

Member of the Monte Cristo Limestone in southern 

Arizona (Brenckle, 1970; Mamet and Skipp, 1970). 

FACIES AND ENVIRONMENTS OF DEPOSITION 

The thin- bedded echinoderm- bryozoan- brachiopod 

packstones of the Kinkead Spring Limestone indicate 

deposition on an open platform marine environment. 

The ooid algae-foraminifer packstones to grainstones 

indicate a shallow, shoaling water environment of deposition. 

ANTELOPE RANGE FORMATION (NEW NAME) 

The Antelope Range Formation is here named from 

outcrops in sec. 22, T. 16 N., R. 51 E., in the northern 

Antelope Range. It is also recognized west of hill 7731 

and elsewhere in the southern Fish Creek Range. Its 

thickness is unknown for, although the basal contact is 

present in many places, the upper part is faulted or 

eroded out. 

LITIIOLOGY 

Because of structural complications and limited exposures, the precise sequence of rock types and internal variation is uncertain. Where the base is exposed 

there is a sequence of perhaps as much as 30 m of 

dark-yellowish-orange to light- brown-weathering 

sandstone. The sandstones are quite similar to those of 

the Diamond Peak Formation, although in the Diamond 

Peak the ratio of chert to quartz and feldspar is high 

and the grains are tightly sutured. Most beds contain 

grains that range from very fine to coarse, and range 

from angular to rounded. Other beds are better sorted 

and contain grains that are subequant and well 

rounded. 

There is considerable variation in quartz plus feldspar 

grains versus those of chert and of lithic clasts. Quartz 

plus feldspar makes up between an estimated 25 and 75 

percent of the rock (mainly more than 50 percent), 

chert between 5 and 35 percent, and lithic clasts from 

20 to 40 percent. Quartz is considerably more common 

than the feldspar, which is estimated at 5 to 10 percent 

of the total quartz plus feldspar. The lithic clasts are 

mainly derived from shale. Blebs of ferruginous material are scattered through most of the sandstone and 

are probably the source of the dark-yellowish-orange 

color. The sandstone here and there contains pebbly 

zones. Sparse interstitial calcite is present in places. 

The rock above the sandstone is mainly a silty shale or 

very thin bedded, platy siltstone, both of which are 

olive gray and slope forming. Medium-gray shale is 

also present locally. A tan-colored limestone, found 

about 1-1/2 km north of hill 7473 in the southern Fish 

Creek Range, may be part of the Antelope Range Formation. 

In the northern Antelope Range, the contact of the 

Antelope Range Formation with the Kinkead Spring 

Limestone is represented by a sharp change from 

medium-gray detrital limestone, below, to moderate 

yellowish-orange sandstone, above. In the southern 

Fish Creek Range, the Antelope Range Formation rests 

unconformably on the Devils Gate Limestone-there 

the Joana Limestone, the Pilot Shale, and an indeterminate amount of the upper part of the Devils Gate 

have been removed by pre-Antelope Range Formation 

erosion. Geologic mapping by Hose ( unpub. data) 

suggests that the contact may be a thrust fault of unknown age, rather than a depositional contact. 

BIOS1RATIGRAPHY 

Calcareous concretions from a silty shale in the 

northern Antelope Range yielded the following conodonts: Palmatolepis of the P. glabra Ulrich and Bassler 

group, Polygnathus cf. P. inornatus Branson, and 

Siphonodella isosticha Cooper. Similar mixed Devonian 

and Mississippian conodonts were found in the southern Fish Creek Range in limestone beds that are believed to belong in the Antelope Range Formation. Because of poor exposures, however, we are not entirely 

certain of this interpretation. In any case, the Antelope 

Range Formation is considered Mississippian and must 

be Osagean or younger because of its stratigraphic position above the Osagean Kinkead Spring Limestone. 

Aside from scattered sparse plant remains found in 

some of the sandstone beds, no megafossils have been 

found. Samples collected for pollen and spores (USGS 

nos. D5174, D5175, D5176, D5181) yielded 

palynomorphs that R. H. Tschudy (written commun., 

197 4) believes to represent the taxa Leiosphaera and 

Tasmanites. Tasmanites, and to a lesser degree Leiosphaera, are common in the Devonian,but in the absence of other taxa, could represent Lower Mississippian. 

Tasmanites and Leiosphaera are probably algal cysts 

representing marine deposition. The above samples 

yielded 2 specimens of trilete spores. Such spores are 

common to nearshore marine and nonmarine deposition sites. My best estimate is that if these fossils are in 

place and not redeposited these samples represent the 

Devonian or Lower Mississippian. Mamet found in thin 

section in a pelletoidal spiculite from the lower part of 

the Antelope Range Formation, Archaesphaera sp., Calcisphaera laevis Williamson, Parathurammina sp., and 

Vicinesphaera sp. He concluded that the youngest possible age was middle Carboniferous and the probable 

age was early Carboniferous. 
DISCUSSION 15 

If the sandstone-shale sequence of the northern Antelope Range (Antelope Range Formation) is indeed 

correlative genetically or otherwise with the rocks of 

near identity in the southern Fish Creek Range from 

whence these samples were obtained, then the Fish 

Creek H.ange sequence of the Antelope H.ange Formation must also be Osagean or younger Mississippian. 

Despite the great similarity of the Antelope Range 

Formation in the northern Antel<;>pe Range to the 

sandstone and shale sequence in the Fish Creek Range, 

there is no absolute certainty that they are precisely 

equivalent temporarily. Aside from the great lithic 

similarity, the other most important criterion for correlation is the profound unconformity at the base of the 

sandstone-shale sequence in both the Antelope and 

Fish Creek Ranges. 

DEPOSITIONAL ENVIRONMENT 

The presence of plant remains in the sandstone and 

nearshore marine and nonmarine spores in the silty 

shale suggest that the sequence accumulated in an estuarine or deltaic environment. 

DISCUSSION 

The Devonian and Mississippian strata of the northern Antelope Range have some degree of similarity to 

the sequence in the southern Fish Creek Range about 

10 km to the east (fig. 7). However, there are also 

some noteworthy differences in the section. Some of 

the contrasts are normal stratigraphic and geographic 

variations, whereas others undoubtedly result from 

telescoping along thrust faults. Figure 7 shows that the 

Beacon Peak Dolomite and McColley Canyon Formation 

are present in both ranges. The Sentinel Mountain 

Dolomite [of the southern Diamond Mountains] is present in the southern Fish Creek Range but absent in 

the Antelope Range. The Woodpecker Limestone, which 

lies above the Sentinel Mountain Dolomite in the 

southern Diamond Mountains and which should be present in the subsurface of southern Fish Creek Range, is 

partly equivalent to the Denay Limestone. 

The South Hill Sandstone, which crops out in small 

fault blocks in the southern Fish Creek Range, is not 

present in the Antelope Range. The Bay State Dolomite 

of the southern Fish Creek Range is temporally correlative with the lower part of the Fenstermaker Wash 

Formation but differs from it in that it is finer grained. 

The Devils Gate Limestone is lime mudstone whereas 

the Fenstermaker Wash is mainly brachiopodechinoderm-peloid packstone and grainstone. Two Mississippian units of the northern Antelope Range, the 

Davis Spring Formation and the Kinkead Spring Limestone, are unconformably overlapped by the Antelope 

Range Formation and are altogether absent in the Fish 

Creek Range and have no known lithic counterpart east 

of the Fish Creek Range. The Kinkead Spring Limestone is recognized to the southwest in the Dobbin 

Summit area of the Monitor Range. 

In the northern part of the Cockalorum Wash quadrangle in the southern Fish Creek Range, the Antelope 

Range Formation rests on the Devils Gate Limestone. 

There the upper part of the Devils Gate and the overlying Chainman Shale, Joana Limestone, and Pilot Shale 

are absent. However, in the more southerly parts of the 

Fish Creek Range a Middle Devonian limestone unit 

plus a unit that greatly resembles the Pilot Shale and 

which is the same age, is present. The combined limestone and shale were included with other strata in the 

Cockalorum Wash Formation by Merriam ( 1973). 

The Antelope Range Formation occurs in both the 

northern Antelope and southern Fish Creek Ranges. In 

the Fish Creek Range it appears to be overthrust by an 

unnamed Mississippian unit quite different from any 

unit heretofore described. It is a sequence of lightyellowish- gray siliceous mudstone, siltstone, claystone, 

and some chert, that contains limestone beds of Osagean age low in the section (A. K. Armstrong, written 

commun., 1977). This siliceous Mississippian formation 

is in turn overthrust by an incomplete siliceous 

mudstone sequence of Late Devonian age assigned to 

the Woodruff Formation. 
16 DEVONIAN AND MISSISSIPPIAN ROCKS, NORTHERN ANTELOPE RANGE, NEVADA 

~ en w Northern 

~ w (!) Antelope 

~ ffi ;:! Range 

~(/)--+-(/)~~(/)--~-----~ 

i ~ 'i£f~ E~~~::n z 

<( 

[[ 

~ 

(/) 

(/) 

(ii 

(/) 

~ 

z 

<( 

z 

0 

> w 

c 

; 

0 

...J 

f.-?-

G) 

=a 

"C 

~ 

f---

0 ~. 

c: 

cu 

G) 

0) 

cu 

!/) 

0 1

111 Kinkead Spring 

Limestone 

I l 

~~~ Fenstermaker • Wash Formation 

I I 

I I 

1-r-...... 1~ ....... Denay 

~T~~ ~ :cj Limestone 

~ 

McColley 

Canyon 

Formation 

Southern 

Fish Creek 

Range 

METERS 

rO 

50 

1- 100 

200 

300 

Devils Gate 

Limestone 

Newark Mountains 

Alhambra Hills 

(after Nolan and 

others, 1956) 

I I 

I 

I I 

1 

I 1 

I 

I 

I 

I 

I I 

I 

I I 

I 

/ 

/ 

/ / 

/ / 

/ / / / 

/ / / / 

/ / / / 

~/ I~H_L 

~~peeker ~ / / 

~ 

~ 

Limestone -5------+ 

Sentinel Mountain 

Dolomite 

Oxyoke Canyon 

Sandstone 

/ 

/ / / / 

/ / 

/ / 

/ / 

.:...:It:.• 3;· --------------------------------

_l_L_Ii~tB~e:a:c:o:n~P~e:a~k~D~olomite Beacon 

Peak 

Dolomite 

9-11 KILOMETERS 25 KILOMETERS 

FIGURE 7.-Correlation of Devonian and Mississippian rocks in northern Antelope Range, southern Fish Creek Range, and Newark Mountains. 

(See figure 5 for explanation of symbols.) 
REFERENCES CITED 17 

REFERENCES CITED 

Armstrong, A. K., and Mamet, B. L., 1977, Carboniferous microfacies, 

microfossils, and corals, Lisburne Group, Artie Alaska: U.S. 

Geological Survey Professional Paper 849, 144 p. 

__ 1978, The Mississippian system of southwestern New Mexico and 

southeastern Arizona: New Mexico Geological Society Guidebook, 

29th Field Conference, p. 183-192. 

Bamber, E. W., and Mamet, B. L., 1978, Carboniferous biostratigraphy 

and correlation, northeastern British Columbia and southwestern 

District of Mackenzie: Geological Survey of Canada Bulletin 266, 

65 p. 

Brenckle, P. L., 1970, Smaller Mississippian and Lower Pennsylvanian 

calcareous foraminifera from Nevada: Cushman Foundation for 

Foraminiferal Research Special Publication no. 11, 82 p. 

Carlisle, D., Murphy, M.A., Nelson, C. A., and Winterer, E. L., 1957, 

Devonian stratigraphy of Sulphur Springs and Pinyon Canyon 

Range, Nevada: American Association of Petroleum Geologists Bul· 

letin, v. 41, p. 2175-2191. 

Carls, Peter, and Gandl, Josef, 1969, Stratigraphie und conodonten 

des Unter-Devons der Ostlichern lberischen Ketten (NE-Spanien): 

Neues Jahrbuch flir Geologie und Pafaontologie Abhandlungen, v. 

132, p. 155-218. 

Folk, R. L., and Land, L. S., 1975, Mg/Ca ratio and salinity: Two con· 

trois over crystallization of dolomite: American Association of Petroleum Geologists Bulletin, v. 59, no. 1, p. 60-68. 

Glenister, B. F., Klapper, Gilbert, and Chauff, K. M., 1976, Conodont 

pearls?: Science, v. 193, p. 571-573. 

Johnson, J. G., 1962, Lower Devonian·Middle Devonian boundary in 

central Nevada: American Association of Petroleum Geologists Bulletin, v. 46, no. 4, p. 542-546. 

-- 1966, Middle Devonian brachiopods from the Roberts Mountains, 

central Nevada: Paleontology, v. 9, p. 152-181, pls. 23-27. 

Klapper, Gilbert, 1977, Lower and Middle Devonian conodont sequence 

in central Nevada, in Murphy, M.A., Berry, W. B. N., and 

Sandberg, C. A., eds., Western North America-Devonian: River· 

side, California University, Riverside Campus Museum Contribution No.4, p. 33-54. 

Mamet, B. L., 1976, An atlas of microfacies in Carboniferous carbonates of the Canadian Cordillera: Geological Survey of Canada 

Bulletin 255, 131 p. 

Mamet, B. L., and Skipp, B. A., 1970, Lower carboniferous calcareous 

foraminifera; pr€liminary zonation and stratigraphic implications 

for the Mississippian of North America: Congresse Internationale 

Stratigraphie et Geologie Carbonifere, 6th, Sheffield, 1967, 

Comptes Rendus, v. 3, p. 1129-1146. 

Matti, Johathan, 1979, Depositional history of middle Paleozoic carbonate rocks deposited at an ancient continental margin, central 

Nevada: Stanford, Calif., Stanford University, Ph. D. thesis, 485 

p. 

Merriam, C. W., 1973, Middle Devonian rugose corals of the central 

Great Basin: U.S. Geological Survey Professional Paper 799, 53 p. 

Nolan, T. B., Merriam, C. W., and Williams, J. S., 1956, The strati· 

graphic section in the vicinity of Eureka, Nevada: U.S. Geological 

Survey Professional Paper 276, 77 p. 

Osmond, J. S., 1954, Dolomites in the Silurian and Devonian of eastcentral Nevada: American Association of Petroleum Geologists Bulletin, v. 38, no. 9, p. 1911-1956. 

Sandberg, C. A., and Gutschick, R. C., 1978, Biostratigrahic guide to 

Upper Devonian and Mississippian rocks along the Wasatch front 

and Cordilleran hingeline, Utah: U.S. Geological Survey Open-File 

Report 78-351, 52 p. 

Sandberg, C. A., and Poole, F. G., 1977, Conodont biostratigraphy and 

depositional complexes of Upper Devonian cratonic-platform and 

continental-shelf rocks in the western United States, in Murphy, 

M.A., Berry, W. B. N., and Sandberg, C. A., eds., Western North 

America-Devonian: Riverside, California University, Riverside 

Campus Museum Contribution 4, p. 144-182. 

Sando, W. J., Mamet, B. L., and Dutro, J. T., Jr., 1969, Carboniferous 

megafauna! and microfauna! zonation in the northern Cordillera of 

the United States: U.S. Geological Survey Professional Paper 

613-E, p. E7-E29. 

Skipp, B., 1969, Foraminifera, in McKee, E. D., and Gutschick, R. C., 

eds., History of the Redwall Limestone of northern Arizona, Chap· 

ter 5: Geological Society of America Memoir 114, p. 173-255. 

Weddige, Karsten, and Ziegler, Willi, 1976, The significance of 

Icriodus-Polygnathus ratios in limestones from the type Eifelian, 

Germany: Geological Association of Canada Special Paper 15, p. 

187-199. 

Ziegler, Willi, 1966, Eine Verfeinerung der Conodontengliederung an 

der Grenze Mittel· /Oberdevon: Fortschrifte in der Geologie von 

Rheinland und Westfalen, v. 9, p. 647-676. 

Ziegler, Willi, Klapper, Gilbert, and Johnson, J. G., 1976, Redefinition 

and subdivision of the varcus Zone (Conodonts, Middle-?Upper 

Devonian) in Europe and North America: Geologica et Paleon· 

tologia, v. 10, p. 109-140. 

Alhambra Hills, 9 

Ancryodella buckeyensis, 10; pl. 8 

Antelope Range, 15 

Antelope Range Formation, 1, 14 

Antelope Valley Limestone, 13; pl. 8 

Archaesphaera sp., 14 

Asphaltinella sp., 12 

asymmetricus Subzone, Polygnathus, 10 

australis Zone, Tortodus kockelianus, 9 

Bay State Dolomite, 9, 15 

Beacon Peak Dolomite, 1, 5, 15 

beckmanni, Pseudoneotodus, 5 

brachiopods, 8, 9 

Brunsiina sp., 12 

bryozoans, 9 

buckeyensis, Ancryodella, 10; pl. 8 

Calcisphaera laevis, 12, 14 

sp., 12 

celtibericus, Icriodus huddlei, 7, 8; pl. 7 

Chainman Shale, 15 

Cockalorum Wash Formation, 15 

Coleodus sp., 13; pl. 8 

Columbiapora johnsoni, 12 

sp., 12 

communis, Polygnathus, 10, 13; pl. 8 

Conodonts, 1, 7, 8, 10, 12, 13, 14; pls. 7, 8 

Corals, 8, 9 

corniger, Icriodus, 8; pl. 7 

costatus costatus Zone, Polygnathus, 9 

costatus Zone, Polygnathus, 9 

curvicauda, Icriodus huddlei, 7 

Davis Spring Formation, 1, 10, 15; pls. 6, 8 

decorosus, Polygnathus, 10; pl. 8 

dehiscens, Polygnathus, 8 

Zone, Polygnathus, 7 

delicata, Kamaena, 12 

delicatus, Gnathodus, 11, 13 

Denay Limestone, 1, 8, 15; pl. 3 

Denay Valley, 8 

Devils Gate Limestone, 8, 14, 15 

Diamond Mountains, 9, 15 

Diamond Peak Formation, 14 

duplicata, Siphonodella, 13; pl. 8 

Earlandia sp., 12 

Egan Range, 5 

Eognathodus sulcatus, 7 

sulcatus sulcatus Zone, 7 

Eovolutina sp., 12 

excavata, Ozarkodina, 7 

exigua philipi, Pandorinellina, 7; pl. 7 

Fenstermaker Wash Formation, 1, 9, 15; 

pls. 4, 5, 8 2 

Fish Creek Range, 5, 14, 15 

Foraminifers, 13 

Gastropods, 5 

gigas Subzone, Palmatolepis, 10 

glabra, Palmatolepis, 11, 13, 14; pl. 8 

Glomospiranella sp., 12 

Gnathodus delicatus, 10, 13 

punctatus, 11, 13; pl. 8 

Grays Canyon Limestone Member, 5 

gronbergi, Polygnathus, 7, 8; pl. 7 

Zone, Polygnathus, 8 

Halysites, 5 

hassi, Palmatolepis, 10; pl. 8 

huddlei, Icriodus, pl. 7 

celtibericus, Icriodus, 7, 8; pl. 7 

curvicauda, Icriodus, 7 

INDEX 

[Italic page numbers indicate both major references and descriptions] 

Icriodus, 7; pl. 8 

corniger, 8; pl. 7 

huddlei, pl. 7 

celtibericus, 7, 8; pl. 7 

curvicauda, 7 

symmetricus, 10; pl. 8 

inornatus, Polygnathus, 14 

insita, Pandorinellina, 10; pl. 8 

Introduction, 1 

isosticha, Siphonodella, 11, 13, 14; 

pl. 8, 3 

Issinella sp., 12 

Joana Limestone, 14, 15 

johnsoni, Columbiapora, 12 

Ozarkodina, 5, 7 

Kamaena sp., 12 

Kamaena delicata, 12 

Kamaenella sp., 12 

Kinkead Spring Limestone, 1, 12; pls. 6, 8 

kockelianus, Tortodus, 9 

Tortodus kockelianus, 8, 9; pl. 7 

australis Zone, Tortodus, 9 

kockelianus, Tortodus, 8, 9; pl. 7 

Zone, Tortodus, 9 

Zone, Tortodus kockelianus, 9 

laevis, Calcisphaera, 12, 14 

lahuseni, Palaeoberesella, 12 

Latiendothyra sp., 12 

Leiosphaera, 14 

linguiformis, Polygnathus linguiformis, 9 

linguiformis, Polygnathus, 9 

Lone Mountain Dolomite, 5 

McColley Canyon Formation, 1, 5, 15; pls. 1, 2, 5 

miae, Pandorinellina steinhornensis, 7, 8; pl. 7 

Moravammina sp., 12 

Nevada Formation, 5 

Newark Mountain, 9 

Ninemile Canyon, 12, 4 

norrisi, Polygnathus, 10; pl. 8 

Nostocites sp., 12 

Nowakia sp., 8, 9 

Ozarkodina, D Zone, 7 

excavata, 7 

johnsoni, 5, 7 

remscheidensis, 5 

Pahranagat Range, 5 

Palaeoberesella lahuseni, 12 

sp., 12 

Paleocyclus sp., 5 

Palmatolepis gigas Subzone, 10 

glabra, 11, 13, 14; pl. 8 

hassi, 10; pl. 8 

perlobata, pl. 8 

proversa, 10 

Pandorinellina, 7 

exigua philipi, 7; pl. 7 

insita, 10; pl. 8 

steinhornensis miae, 7, 8; pl. 7 

Parathurammina sp., 12, 14 

parawebbi, Polygnathus, 8, 9, 10; pls. 7, 8 

Pedavis pesavis Zone, 5, 7 

Pekiskopora sp., 12 

perlobata, Palmatolepis, pl. 8 

pesavis Zone, Pedavis, 5, 7 

philipi, Pandorinellina exigua, 7; 

pl. 7, 5 

Pilot Shale, 14, 15 

Polygnathus, 7, 8 

asymmetricus Subzone, 10 

Polygnathus -Continued 

communis, 11, 13; pl. 8 

costatus costatus Zone, 9 

decorosus, 10; pl. 8 

dehiscens, 7, 8 

Zone, 7 

gronbergi, 7, 8; pl. 7 

Zone, 8 

inornatus, 14 

linguiformis linguiformis, 9 

norrisi, 10; pl. 8 

parawebbi, 8, 9, 10; pls. 7, 8 

robusticostatus, 9 

semicostatus, 11, 13; pl. 8 

serotinus Zone, 8 

trigonicus, 9; pl. 7 

varcus, pl. 8 

Subzone, 10 

Zone, 9, 10 

primaeva, Septaglomospiranella, 12 

Proninella sp., 12 

proversa, Palmatolepis, 10 

Pseudoneotodus beckmanni, 5 

punctatus, Gnathodus, 11, 13; pl. 8 

Receptaculites sp., 9 

Rectoseptaglomosptranella sp., 12, 13 

remscheidensis, Ozarkodina, 5 

Roberts M@untains, 8 

robusticostatus, Polygnathus, 9 

semicostatus, Polygnathus, 11, 13; pl. 8 

Sentinal Mountain Dolomite, 9, 14 

Septabrunsiina sp., 12, 13 

Septaglomospiranella primaeva, 12 

sp., 12 

Septatournayella sp., 12 

serotinus Zone, Polygnathus, 8 

Sevy Dolomite, 5 

Simpson Park Mountains, 8 

Siphonodella duplicata, 13; pl. 8 

isosticha, 11, 13, 14; pl. 8 

South Hill Sandstone, 15 

Sphaeroporella sp., 12 

Spinoendothyra sp., 12, 13 

steinhornensis miae, Pandorinellina, 7, 8; pl. 7 

Striatolina sp., 8, 9 

sulcatus, Eognathodus, 7 

sulcatus Zone, Eognathodus, 7 

Zone, Eognathodus, 7 

Sulphur Springs Range, 5 

symmetricus, Icriodus, 10; pl. 8 

Tasmanites sp., 14 

Tentaculites sp., 8 

Tortodus kockelianus, 9 

kockelianus australis Zone, 9 

kockelianus, 8, 9; pl. 7 

Zone, 9 

trigonicus, Polygnathus, 9; pl. 7 

tuberculata, Tuerendothyra, 12, 13 

Tuberendothyra tuberculata, 12, 13 

sp., 12 

Upper Davis Spring, 10 

varcus, Polygnathus, pl. 8 

Subzone, Polygnathus, 10 

Zone, Polygnathus, 9, 10 

Vicinesphaera sp., 14 

Willow Creek Canyon, 8 

Woodpecker Limestone, 9, 15 

Woodruff Formation, 15 

19 

PlATES 1-8 

[Contact photographs of the plates in this report are available, at cost, from 

the U.S. Geological Survey Library, Federal Center, Denver, Colorado 80225] 
PLATE 1 

FIGURES 1-6. McColley Canyon Formation 

1, 2, 3. Specimen 40 m; 1, plane-light photomicrograph of a pellet-brachiopod-echinoderm packstone; 2, scanning electron micrograph of round object, possibly a 

calcisphere or an ostracode; interior is filled with 5-,um calcite rhombs and intercrystalline clay minerals. Calcite surrounding shell is 10-20 ,urn in size; some 

dolomite (D) is present. 3, Scanning electron micrograph of micrite matrix of 

the packstone, with 5- to 10-,um calcite rhombs and clay minerals between the 

calcite crystals. 

4. Specimen 44 m; scanning electron micrograph of a dolomitic-argillaceous 

packstone; euhedral rhombs of dolomite (D); abundant clay minerals are be· 

tween the calcite crystals. 

5. Specimen 75 m; scanning electron micrograph of dolomitic-pellet packstone. The 

subhedral dolomite rhombs (D) are from a few to 30 ,urn in size, matrix is 5- to 

10-,um calcite rhombs; lower right side shows a transverse section of a foliated 

brachiopod shell. 

6. Specimen 98 m; plane-light photomicrograph of pellet-calcisphere-dolomitic 

packstone. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 1 

E 0.2 mm F 

McCOLLEY CANYON FORMATION 
FIGURES 

PLATE2 

1, 2. McColley Canyon Formation 

1. Specimen 112 m; scanning electron micrograph of bryozoan packstone. Interiors 

of fossils are filled with a matrix of clay minerals and anhedral calcite rhombs. 

Some dolomite (D) is present. 

2. Specimen 149 m; scanning electron micrograph of insoluble residue sample from 

lime mudstone. Broken sponge spicule? preserved by dolomite crystals. 

3-6. Denay Limestone 

3, 4. Specimen 202 m; 3, plane-light photomicrograph tentaculites-packstone; 4, 

scanning electron micrograph of argillaceous-dolomite-tentaculites wackestone; 

dolomite (D). 

5. Specimen 288 m; scanning electron micrograph of argillaceous-dolomitic 

brachiopod-pellet wackestone; dolomite (D) and intercrystalline clay minerals 

can be seen in a calcite micrite matrix. 

6. Specimen 316 m; scanning electron micrograph of dolomitic lime mudstone. A 

stylolite (lower left to upper right) is outlined by a slight increase in dolomite 

(D) rhombs. The rock is relatively free of clay minerals. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 2 

20 !Lm 1 E 30 !Lm 1 F 

McCOLLEY CANYON FORMATION, FIGURES A ,B;AND DENAY LIMESTONE, FIGURES C-F 
FIGURES 

PLATE 3 

1, 2. De nay Limestone 

1. Specimen 410 m; l, plane-light photomicrograph of a pellet-echinodermdolomitic packstone to grainstone. 2, scanning electron micrograph, showing the 

peloids to contain 2- to 6-J.tm anhedral calcite crystals and 5- to 10-J.tm subhedral 

dolomite rhombs. The calcite matrix between the peloids is microspar from 30 to 

70 Jim in size and is relatively free of dolomite 

3-6. Fenstermaker Wash Formation 

3, 4. Specimen 451 m; 3, plane-light photomicrograph, echinoderm-bryozoan 

packstone; 4, scanning electron micrograph of a bryzoan fragment surrounded 

by microspar and sparry calcite rhombs 10 to 30 Jim in size. 

5, 6. Specimen 487 m; 5, plane-light photomicrograph of dolomitic-pellet-lump 

packstone; 6, scanning electron micrograph showing subhedral dolomite rhombs 

(D) in a matrix of 4- to 10-J.t calcite rombs. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 3 

1 mm 

1 20011-m 1 E 1 3011-m F 

DENAY LIMESTONE. FIGURES A.B;AND FENSTERMAKER WASH FORMATION. FIGURES C-F 
FIGURES 

PLATE 4 

1-6. Fenstermaker Wash Formation 

1, 2. Specimen 501 m; 1, plane-light photomicrograph, arenaceous- dolomiticbryozoan packstone; 2, scanning electron micrograph of a dolomite rhomb undergoing calcitification. Another is present in figure 1. Dolomite rhombs show 

irregular sides due to replacement by calcite. 

3, 4. Specimen 526 m; pellet-dolomitic packstone. 3, Plane-light photomicrograph of 

iron-rich calcite-zone dolomite (FD) rhombs. 4, scanning electron micrograph of 

an etched iron-rich calcite zone in a dolomite rhomb surrounded by a matrix of 

anhedral calcite grains 4 to 6 ,urn in size. 

5. Specimen 545 m; arenaceous dolomite. Scanning electron micrograph of an 

etched surface of the dolomite, illustrating intercrystalline porosity and the 

euhedral dolomite rhombs. 

6. Specimen 560 m; scanning electron micrograph of dolomitic packstone showing 

range in dolomite size from 4-,u to 100-,u rhombs. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 4 

E F 

FENSTERMAKER WASH FORMATION 
PLATE 5 

FIGURES 1-5. Fenstermaker Wash Formation 

1, 2. Specimen 596 m; 1, plane·light photomicrograph, peloid-mud lump grainstone, 

space between particles is filled by sparry calcite; some peloids show evidence of 

concentric lamellar patterns or ooid coatings. Fossil fragments are echinoderms 

and brachiopods. Large ooid in lower left corner has a sparry calcite center of 

nucleus, which probably was originally aragonite that was removed by leaching 

and replaced by calcite. 2, Scanning electron micrograph of peloids made up of 

micrite-size calcite rhombs, 5 ,urn or less in size; area between peloids is filled by 

large ( 10 to 50 ,urn) rhombs of calcite. White crystals in relief between calcite 

crystals are detrital clay minerals. 

3, 4, 5. Specimen 609 m; 3, plane-light photomicrograph, peloid-calcisphere-lump 

packstone to grainstone. 4, 5, scanning electron micrographs. 4, Circular peloid 

contains impurities of clay minerals and dolomite rhombs. 5, Partial view of 

three peloids composed of micrite calcite rhombs with some clay minerals. Area 

between rhombs is filled by sparry calcite. 

6. McColley Canyon Formation 

6. Specimen 42 m; scanning electron micrograph of the insoluble residue, rounded 

400- to 500-,um grains of quartz sand. Surfaces of grains have a chalcedony 

overgrowth that protruded into the space between calcite crystals. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 5 

20JLm E 1 100J.Lm F 

FENSTERMAKER WASH FORMATION, FIGURES A,E; AND McCOLLEY CANYON FORMATION, FIGURE F 
FIGURE 

PLATE 6 

[Plane-light photomicrographs] 

1. Davis Spring Formation 

1. Specimen 32 m; siliceous-radiolarian-spiculitic-argillaceous dolomite. Section of 

a radiolarian (silica) with spines is in center of photograph. 

2-6. Kinkead Spring Limestone 

2. Specimen 132 m; brachiopod-echinoderm-peloid-ooid packstone to grainstone. 

Echinoderm fragments have syntaxial overgrowths of calcite. The rock is composed of sedimentary particles that reflect diverse origins: peloids, broken fossil 

remains, and oolitic coated particles. Micrite converted to microspar. 

3. Specimen 150 m; peloid-ooid packstone to grainstone. This rock type is typical of 

the zone 8 and 8 /9 ooid beds in Mississippian carbonate rocks. Micrite between 

ooids has in part been converted to microspar. 

4. Specimen 170 m; ostracode-brachiopod wackestone, composed of well-sorted 

fossil fragments and calcareous spiculites in a 2- to 4-J.Lm calcite micrite matrix. 

5. Specimen 170.5 m; ostracode-calcisphere-spiculite wackestone. 

6. Specimen 178 m; ostracode-calcisphere-spiculite wackestone. Subrounded 

quartz sand grains 75 to 100 .urn in size form 1 to 3 percent of rock. Fossil fragments are rounded and well sorted. Lime mudstone (micrite) matrix is 2- to 

4-J.Lm calcite crystals. This wackestone microfacies is typical of the rock type 

found associated with ooid packstones and grainstones. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 6 

1 mm 

0.2 mm E 0.2 mm F 

DAVIS SPRING FORMATION, FIGURE A ; AND KINKEAD SPRING LIMESTONE, FIGURES B-F 
PLATE 7 

FIGURES 1-17. Scanning electron micrographs of biostratigraphically significant conodonts 

from the McColley Canyon Formation. Stratigraphic position of USGS collection 

numbers is shown in text figure 5. 

1-3. Icriodus huddlei celtihericus Carls and Gandl. Upper views of I elements showing 

variation in the angle between the outer lateral process and the main platform. 

1. USNM 270001, X 45, USGS coHn. 9638-SD. 

2, 3. USNM 270002,270003, X 50, USGS coHn. 9637-SD. 

4-7. Icriodus huddlei? n. subsp. Upper and lower views of I elements. Representatives 

of this form occur in the lower 153 m of the McColley Canyon Formation. 

4, 5. USNM 270004, X 50, USGS coHn. 9637-SD. 

6, 7. USNM 270005, X 40, USGS coHn. 9813-SD. 

8-9. Icriodus huddlei celtihericus Carls and Gandl. Anterior and posterior views of S2 

elements, USNM 270006, 270007, X 45 and X 75. USGS coHn. 9654-SD. 

10-11. Pandorinellina exigua philipi (Klapper). Upper and lateral views of P element, 

USNM 270008, X 50. USGS coHn. 9817-SD. 

12-13. Pandorinellina steinhornensis miae Bultynck. Upper and oblique lateral views of P 

element, USNM 270009, X 50. USGS coHn. 9818-SD. 

14-15. Polygnathus gronbergi Klapper and Johnson. Upper and lower views of P element, USNM 270010, X 50 USGS coHn. 9818-SD. 

16-17. Icriodus corniger Wittekindt. Upper and lower views of I elements, USNM 

270011, 270012,X 50. USGS coHn. 9639-SD. 

18-23. Scanning electron micrographs of a "conodont pearl" and biostratigraphically 

significant conodonts from the Denay Limestone. Stratigraphic position of 

USGS collection numbers is shown in text figure 5. 

18. "Conodont pearl" showing dimple. USNM 270013, X 100. USGS coHn. 9819-SD. 

19. Polygnathus trigonicus Bischoff and Ziegler. Upper view of P element, USNM 

270014, X 75. USGS coHn. 9819-SD. 

20, 21. Polygnathus parawebbi Chatterton. Upper views of P elements, USNM 270015, 

270016, X 50 and X 40. USGS collns. 9814-SD and 9819-SD. 

22, 23. Tortodus kockelianus kockelianus Bischoff and Ziegler. Upper and lower views of 

P element, USNM 270017, X 75. USGS coHn. 9814-SD. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182, PLATE 7 

BIOSTRATIGRAPHICALL Y SIGNIFICANT CONODONTS FROM THE McCOLLEY CANYON FORMATION AND 

DENA Y LIMESTONE 
FIGURES 

PLATE 8 

1-12. Scanning electron micrographs of biostratigraphically significant conodonts 

from the Fenstermaker Wash Formation. Stratigraphic position of USGS collection numbers is shown in text figure 5. 

1, 2. Polygnathus parawebbi Chatterton. Upper and lower views of P elements, USNM 

270018, 270019, X 50. USGS coHn 9815-SD. 

3. Polygnathus varcus Stauffer. Upper view of P element, USNM 270020, X 75. 

USGS colin. 9645-SD. 

4, 5. Polygnathus decorosus s.l. Upper and lower views of P elements, USNM 270021, 

270022, X 50. USGS coHn. 9972-SD. 

6. Polygnathus norrisi Uyeno. Upper view of P element, USNM 270023, X 63. USGS 

9648-SD. 

7. Pandorinellina insita (Stauffer). Lateral view of P element, USNM 270024, X 

100. USGS colin. 9648-SD. 

8-9. Icriodus symmetricus Branson and Mehl. Upper and lower views of I elements, 

USNM 270025, 270026, X 50. USGS colin. 9972-SD. 

10. Ancyrodella cf. A. buckeyensis Stauffer. Upper view ofP element, USNM 270027, 

X 50. USGS colin. 9972-SD. 

11. Palmatolepis cf. P. prouersa Ziegler. Upper view of P element, USNM 270028, X 

50. USGS colin. 9972-SD. 

12. Palmatolepis cf. P. hassi Muller and Muller. Upper view of P element, USNM 

270029, X 50. USGS colin. 9647-SD. 

13-16. Scanning electron micrographs of redeposited Famennian (figs. 13, 14, and 16) 

and redeposited and (or) indigenous Early Mississippian (fig. 15) condonts from 

the Davis Spring Formation. All specimens X 50 and from USGS coHn. 27377-PC 

(text fig. 6). 

13. Palmatolepis glabra Ulrich and Bassler. Upper view of P element, USNM 270030. 

P. glabra is the most abundant species among the redeposited elements in this 

collection. 

14. Palmatolepis perlobata Ulrich and Bassler. Upper view of P element, USNM 

270031. P. perlobata is one of several species of redeposited Famennian palmatolepids represented by only one or a few specimens in this collection. 

15. Gnathodus punctatus (Cooper). Upper view of incomplete P element, USNM 

270032. 

16. Polygnathus semicostatus Branson and Mehl. Upper view of incomplete P element, USNM 270033. All specimens of this species and at least 90 percent of all 

the other conodonts in the collection are fragmented and abraded. 

17-22. Scanning electron micrographs of redeposited (figs. 17, 18, 20, and 21) and redeposited and (or) indigenous Early Mississippian (figs. 19 and 22) conodonts 

from the Kinkead Spring Limestone (Osagean). Stratigraphic position of USGS 

collection numbers is shown in text figure 6. 

17. Coleodus? sp. Lateral view, USNM 270034, X 40. USGS coHn. 27411-PC. This 

specimen is the only recognizable pre-Devonian redeposited element in our collections from the Kinkead Spring Limestone. Coleodus? sp. is common in shelf 

edge and upper slope facies of the Lower and lower Middle Ordovician Antelope 

Valley Limestone in central Nevada. 

18. Icriodus sp. Upper view of I element, USNM 270035, X 50. USGS colin. 

27413-PC. All our collections from the Kinkead Spring Limestone contain I and 

(or) S2 elements of redeposited Devonian icriodids. 

19. Polygnathus communis Branson and Mehl. Upper view of P element, USNM 

270036, X 50. USGS coHn. 27413-PC. The Kinkead Spring Limestone contains 

Osagean foraminifers and because P. communis is known to occur from the 

Famennian into the middle Osagean, representatives of this species in our collection could be redeposited and (or) indigenous. 

20. Siphonodella isosticha (Cooper). Upper view of P element, USNM 270037, X 40. 

USGS colln. 27411-PC. A redeposited Kinderhookian element. 

21. Siphonodella duplicata (Branson and Mehl). Upper view of P element, USNM 

270038, X 40. USGS colin. 27413-PC. Redeposited Kinderhookian element. 

22. Gnathodus punctatus (Cooper). Upper view of P element, USNM 270039, X 50. 

USGS colln. 27413-PC. A redeposited and (or) indigenous Lower Mississippian element. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1182,PLATE 8 

BIOSTRATIGRAPHICALLY SIGNIFICANT CONODONTS FROM THE FENSTERMAKER WASH AND DAVIS 

SPRING FORMATIONS AND THE KINKEAD SPRING LIMESTONE 

GPO 588-767