Studies of the 

Permian Phosphoria Formation and 

Related Rocks, Great BasinRocky 1\Jountain Region 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-A, B, C, D 

Studies of the 

Permian Phosphoria Formation and 

Related Rocks, Great BasinRocky Mountain Region 

Bruce R. Wardlaw, Editor 

Transgression of the Retort Phosphatic Shale Member of the Phosphoria 

Formation (Permian) in Idaho, Montana, Utah, and Wyoming 

By BRUCE R. WARDLAW 

The Murdock Mountain Formation: a new unit of the 

Permian Park City Group 

By BRUCE R. WARDLAW, JAMES W. COLLINSON, and EDWIN K. MAUGHAN 

Stratigraphy of Park City Group Equivalents in southern Idaho, 

northeastern Nevada, and northwestern Utah 

By BRUCE R. WARDLAW, jAMES W. COLLINSON, and EDWIN K. MAUGHAN 

Biostratigraphic zonation of the Park City Group 

By BRUCE R. WARDLAW and jAMES W. COLLINSON 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-A, B, C, D 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1979 
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary 

GEOLOGICAL SURVEY 

H. William Menard, Director 

Library of Congress catalog-card No. 79-607907 

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

Washington, D.C. 20402 

Stock Number 024-001-03257-1 
CONTENTS 

(Letters designate the chapters} 

Page 

(A) Transgression of the Retort Phosphatic Shale Member of the Phosphoria Formation 

(Permian) in Idaho, Montana, Utah, and Wyoming, by Bruce R. Wardlaw---------- 1 

(B) The Murdock Mountain Formation: a new unit of the Permian Park City Group, by 

Bruce R. Wardlaw, James W. Collinson, and Edwin K. Maughan------------------------- 5 

(C) Stratigraphy of Park City Group Equivalents in southern Idaho, northeastern 

Nevada, and northwestern Utah, by Bruce R. Wardlaw, James W. Collinson, 

and Edwin K. Maughan ---------------------------------------------------------------------------------------- 9 

(D) Biostratigraphic zonation of the Park City Group, by Bruce R. Wardlaw and James 

W. Collinson --------------------------------------------------------------------------------------------------- 17 

III 

Transgression of the 

Retort Phosphatic Shale Member of the 

Phosphoria Formation (Permian) in 

Idaho, Montana, Utah, and Wyoming 

ByBRUCER. WARDLAW 

STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND 

RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-A 
CONTENTS 

Page 

Abstract ------------------------------------------------------------------------------------------------------------------------------------- 1 

Introduction -------------------------------------------------------------------------------------------------------------------------------- 1 

Brachiopod evidence ------------------------------------------------------------------------------------------------------------------ 1 

Montana localities ---------------------------------------------------------------------------------------------------------------- 1 

Idaho localities -----------------------------------------------------------------------------------------------·------------------- 2 

Utah localities ----------------------------------------------------------------------------------------------------------------- 2 

Wyoming localities -------------------------------------------------------------------------------------------------------------- 2 

References cited ------------------------------------------------------------------------------------------------------------------------ 3 

ILLUSTRATIONS 

Page 

FIGURE 1. Map of location of geologic sections-------------------------------------------------------------------- 2 

2. Fence diagram of Retort Phosphatic Shale Member of the Phosphoria Formation, showing occurrences of brachiopods immediately below the Retort--- 3 

3. Diagram of relative age of the base of the Retort Phosphatic Shale Member 

of the Phosphoria Formation in Idaho, Montana, Utah, and Wyoming------ 4 
STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND RELATED ROCKS, 

GREAT BASIN-ROCKY MOUNTAIN REGION 

TRANSGRESSION OF THE RETORT PHOSPHATIC SHALE MEMBER OF 

THE PHOSPHORIA FORMATION (PERMIAN) IN IDAHO, MONTANA, 

UTAH, AND WYOMING 

By BRUCE R. WARDLAW 

ABSTRACT 

The transgression of the Permian Retort Phosphatic Shale 

Member of the Phosphoria Formation is dated by the occurrence of 

diagnostic brachiopods. The complex pattern of this transgression 

reflects the paleogeography and indicates two initial basins of 

deposition: one in southwestern Montana and one in southeastern 

Idaho. 

INTRODUCTION 

Relative ages for the Phosphoria, Park City, and 

Shedhorn Formations of Idaho, Montana, and Wyoming can be determined by an application of the 

regional biostratigraphic zonation proposed by 

Wardlaw and Collinson (1977; 1978a; this volume, 

Chapter D) for the Park City Group in Nevada and 

Utah. Many of the key brachiopods are the same in 

both areas; conodonts also support this determination 

(Wardlaw and Collinson, 1978b, 1979). Most of the 

brachiopod collections referred to in this report are 

listed by Wardlaw (1978). The brachiopods are not 

always present but are prevalent enough for dating the 

time of initial transgression of the Retort Phosphatic 

Shale Member of the Phosphoria Formation. 

Brachiopods are rare and seem to have found it unfavorable to live in the environments of deposition of 

the Phosphoria and Park City Formations in or below 

the Retort Phosphatic Shale Member in much of 

western Wyoming. Elsewhere, in the Retort depositional area, brachiopods seem to be fairly common. 

Wardlaw and Collinson (1977, 1978a) proposed three 

Wordian (lower Guadalupian1

) zones. They are, in 

ascending order: the Thamnosia depressa Zone, the 

Kuvelousia leptosa Zone, and the Yakovlevia 

multistriata-Neogondolella bitteri Zone. The zones 

have since been more simply referred to (Wardlaw, Col1 Assigned to the Early Permian by the U.S. Geological Survey. 

linson, and Maughan, this volume, Chapter C) as the 

Thamnosia, Kuvelousia, and Yakovlevia Zones. All 

three of the diagnostic brachiopods (Thamnosia, 

Kuvelousia, and Yakovlevia) are found in much of the 

area discussed. Other diagnostic brachiopods of the 

Yakovlevia Zone are Timaniella n. sp. and Bathymyonia n. sp. B (Wardlaw and Collinson, 1978a, 1979). 

Because the brachiopods maintain a consistent 

biostratigraphic position over the Great Basin-Rocky 

Mountain area in many different facies, it seems 

reasonable to use the zones as relative time indicators. 

The zones show a complex transgression of the Retort 

Phosphatic Shale Member of the Phosphoria Formation over Wyoming and Utah. Geologic sections used 

to illustrate the transgression are shown in figure 1. 

Figure 2 shows the distribution of the Retort 

Phosphatic Shale Member and the brachiopods that 

occur just below it. Though much of the data is taken 

from the thrust belt in Idaho and Wyoming, and interpretations are made across it, the thrusts do not appear to alter the relative position of each section for the 

scale of this analysis. Sections on different thrust 

plates show similar east-west trends and these trends 

vary north and south. 

BRACHIOPOD EVIDENCE 

MONTANA LOCALITIES 

Dalys Spur.-Thamnosia depressa (Cooper) occurs 

just below the Retort Phosphatic Shale Member in the 

Shedhorn Sandstone, indicating correlation of initial 

deposition of the conformable Retort during the Thamnosia Zone. 

Big Sheep Creek.-Thamnosia depressa (Cooper) occurs just below the Retort in the Shedhorn Sandstone, 

indicating initial deposition of the Retort during the 

Thamnosia Zone. 

1 
2 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

43° 

42° 

A Dalys Spur MONTANA 

r-----------------

1wvoMING 

t''\: /-~:: '1 I 

I 

I 

I 

I 

1 Teton Pass 

UTAH 

FIGURE I.-Location of geologic sections. 

IDAHO LOCALITIES 

Twin 

Creek 

50 

Fall Creek.-N eospirifer striatoparadoxus (Toula) occurs below the Retort in the Franson Member of the 

Park City Formation, along with several other 

brachiopods (Wardlaw, 1978). This probably 

represents a fauna at or near the ThamnosiaKuvelousia zonal boundary. Only a few feet of Retort 

exist here, the majority having been eroded away 

before Triassic deposition. 

Trail Creek.-In the divide between Trail Creek and 

Wood Canyon, Kuvelousia leptosa Waterhouse occurs 

just below the Retort in a cherty carbonate of the Rex 

Chert Member of the Phosphoria Formation, indicating initial deposition of the Retort during the 

Kuvelousia Zone. 

Montpelier Canyon.-Thamnosia depressa (Cooper) 

occurs just below the Retort in the Franson Member of 

the Park City Formation, indicating initial deposition 

of the Retort during the Thamnosia Zone. 

UTAH LOCALITIES 

Crawford Mountains.-No diagnostic fossils exist 

below the Retort, but at the Frank mine prospect, in a 

very thin Retort, occurs an abundant brachiopod fauna 

including Timaniella n. sp. This probably represents 

sedimentation beginning at or near the KuvelousiaYakovlevia zonal boundary. The Retort has been 

greatly reduced by erosion prior to Triassic sedimentation. 

Dry BreadHollow.-Kuvelousia leptosa Waterhouse 

occurs below the Retort in the Franson Member of the 

Park City Formation, indicating initial deposition of 

the Retort during the Kuvelousia Zone. 

WYOMING LOCALITIES 

Teton Pass.-No diagnostic fossils occur below the 

Retort in the Franson Member of the Park City Formation. 

Tosi Creek.-No diagnostic fossils occur below the 

Retort in the Franson Member of the Park City Formation. 

Bull Lake.-Yakovlevia multistriata (Meek) and 

Timaniella n. sp. occur just below the Retort in the 

Franson Member of the Park City Formation. In the 

Ervay Carbonate Member of the Park City Formation 

(just above the Retort), Yakovlevia multistriata 

(Meek), Timaniella n. sp., and Bathymyonia n. sp. B occur at its base. Therefore, diagnostic fossils of the 

Yakovlevia Zone bracket the Retort. 

Anchor Canyon.-Timaniella n. sp. and Bathymyonia n. sp. B occur just below and in the very thin 

Retort, indicating initial deposition of the Retort during the Yakovlevia Zone. 

Twin Creek.-Timaniella n. sp. and Bathymyonia n. 

sp. B occur in the Retort, indicating initial deposition 

of the Retort during the Yakovlevia Zone. 

The inferred age for the base of the Retort (fig. 3), 

along the traverses shown in figure 1, indicates a 

rather straightforward transgression from southwestern Montana into Wyoming through most of 

Wordian time. The pattern is more complex in Idaho 

and Utah, where the complexity of the transgression 

reflects a paleogeography of minor basins and rises 

that were differentially transgressed. It appears that 

the beginning of Retort deposition was nearly 

simultaneous in southwestern Montana and southeastern Idaho, whereas deposition in central-eastern 

Idaho began later. This implies two separate initial 

basins of deposition. A depositional basin developed 

in Utah in middle Wordian time. This basin was separated from the southeastern Idaho basin until late 

Wordian time. 
TRANSGRESSION OF THE RETORT PHOSPHATIC SHALE MEMBER 3 

A 

~ N 

I 

METERS 

20j 

10 

0 

A" 

ZONES DIAGNOSTIC 

BRACHIOPODS 

Yakovlevla Y, T 

Kuvelousla K 

Thamnosla Th 

EXPLANATION 

K Kuvelousla leptosa 

Th Thamnosla depressa 

T Timaniella "pseudocameratus" 

Y Yakovlevla multlstrlata 

F A few fairly diagnostic brachiopods 

N No diagnostic brachiopods 

- Conformable contact 

...-- Unconformable contact 

N 

0 KILOMETERS 50 

I I 

FIGURE 2.-Fence diagram of Retort Phosphatic Shale Member of the Phosphoria Formation, showing occurrences of 

brachiopods immediately below the Retort. Localities as in figure 1. 

REFERENCES CITED 

Wardlaw, B. R., 1978, Update and revision of brachiopod collections 

of the Phosphoria, Park City, and Shedhorn Formations (Permian) of the U.S. Geological Survey: U.S. Geological Survey 

Open-File Report 78-692,81 p. 

Wardlaw, B. R., and Collinson, J. W., 1977, Biostratigraphic zonation of the Park City Group: U.S. Geological Survey Open-File 

Report 77-853, 15 p. 

__ 1978a, Stratigraphic relationship of the Park City Group 

(Permian) in eastern Nevada and Western Utah: American 

Association of Petroleum Geologists Bulletin, v. 62, no. 7, 

p. 1171-1184. 

__ 1978b, Youngest Permian conodont faunas from the Great 

Basin: Geological Society of America Abstracts with Programs, 

v.l0,no.5,p.240-241: 

__ 1979, Youngest Permian conodont faunas from the Great 

Basin: Brigham Young University Geology Studies. (In press.) 
4 

w 

:E 

t= 

z 

c( 

c 

a: 

0 

~ 

PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

Yakovlevia 

Zone 

Kuvelousia 

Zone 

Thamnosia 

Zone 

Yakovlevia 

Zone 

Kuvelousia 

Zone 

Thamnosia 

Zone 

A 

MONTANA 

A 

MONTANA 

/ 

/ 

/ 

,."" / 

/ / / 

/ ,"" 

------

I IDAHO I WYOMING 

IDAHO UTAH 

A' 

A" 

FIGURE 3.-Relative age of the base of the Retort Phosphatic Shale Member of the Phosphoria Formation in Idaho, Montana, Utah, and 

Wyoming, following traverses A-A' and A-A", shown in figure 1. Dashed where inferred. 
The Murdock Mountain Formation: 

A New Unit of the 

Permian Park City Group 

By BRUCE R. WARDLAW, JAMES W. COLLINSON, and EDWIN K. MAUGHAN 

STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND 

RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-B 
CONTENTS 

Page 

A b str act --------------------------------------------------------------------------------------------------------------------------- 5 

Introduction ------------------------------------------------------------------------------------------------------------------------- 5 

Discussion -----------------------------------------·------------------------------------------------------------------------------------ 5 

References cited ---------------------------------------------------------------------------------------------------------------------- 6 

ILLUSTRATIONS 

Page 

FIGURE 4. Map showing location of the type section of the Murdock Mountain Formation, Leach Mountains, Nevada--------------------------------------------------------·--- 6 

5. Columnar section of the Murdock Mountain Formation-------------------------- 7 

6. Diagram of subdivisions of the Permian -------------------------------------------- 8 
STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND RELATED ROCKS, 

GREAT BASIN-ROCKY MOUNTAIN REGION 

THE MURDOCK MOUNTAIN FORMATION: A NEW UNIT OF THE 

PERMIAN PARK CITY GROUP 

By BRUCE R. WARDLAW, jAMES W. COLLINSON/ and EDWIN K. MAUGHAN 

ABSTRACT 

A new formation is proposed for middle Permian rocks of a transitional facies positioned laterally between the Rex Chert Member of 

the Phosphoria Formation in northeastern Utah and southeastern 

Idaho and the Plympton Formation in northeastern Nevada and 

northwestern Utah. 

INTRODUCTION 

The Murdock Mountain Formation is proposed here 

for a sequence of dolomitic chert, dolomite, finegrained sandstone, and siltstone that occurs as a middle formation within the Park City Group of northeastern Nevada and northwestern Utah. The type section is located on the east flank of Murdock Mountain, 

north-center sec. 36, T. 39 N., R. 67 E., Loray 

7¥2-minute quadrangle, Leach Mountains, Elko County, Nev. (fig. 4). The beds form a homoclinal section 

striking N. 39 o E. and dipping at about 27 oW. The formation conformably overlies the Meade Peak 

Phosphatic Shale Tongue of the Phosphoria Formation 

and is conformably overlain by the Gerster Limestone. 

The Murdock Mountain Formation is laterally 

equivalent to the Plympton Formation, also of the 

Park City Group, in west-central Utah and east-central 

Nevada, and to the Rex Chert Member of the 

Phosphoria Formation in southwestern Idaho. (See 

also Chapter C, this volume.) 

DISCUSSION 

A diagrammatic section of the Murdock Mountain 

Formation at the type section is shown in figure 5. The 

formation is 385.5 m thick at the type section. The 

lower contact is gradational; phosphatic mudstone and 

1

Department of Geology, Ohio State University, Columbus, OH; research associate with 

U.S. Geological Survey, Denver, CO. 

phosphorite in the underlying Meade Peak Tongue 

grade upward into less phosphatic beds of cherty 

siltstone, chert, dolomite, and limestone in the basal 

Murdock Mountain Formation. Most of the Murdock 

Mountain Formation is composed of slope-forming 

cherty siltstone, silty chert, fine-grained sandstone, 

and thin beds of dolomite. Thick units of dark-gray 

bedded chert form prominent ledges throughout the sequence. Lateral gradation of chert to cherty limestone 

within beds and relict limestone textures and fabrics in 

the chert indicate that much of the bedded chert formed by secondary replacement of limestone. The chert 

interval near the base of the formation contains less 

secondary chert and is, therefore, much like the chert 

of the Rex Chert Member of the Phosphoria Formation. Two chert units in the lower part of the Gerster 

Limestone in the Leach Mountains (Nevada) and the 

Terrace Mountains (northwestern Utah) probably 

represent tongues of the Murdock Mountain Formation. (See Chapter C.) 

A well-preserved fauna from near the base of the 

Murdock Mountain Formation contains Cancrinella 

phosphatica Girty, Crurithyris arcuata Girty, 

Echinalosia n. sp., Leiorhynchoidea weeksi Girty, 

Hindeodus sp., Neogondolella idahoensis (Youngquist, 

Hawley, and Miller), and Xaniognathus abstractus 

(Clark and Ethington). This fauna indicates a Roadian 

Age (stage name of Furnish, 1973). Diagnostic fossils 

were not found in the middle and upper parts of the formation. However, the overlying Gerster Limestone, 

the upper formation of the Park City Group, has been 

dated as Wordian by its abundant brachiopod and conodont faunas (Wardlaw, 1977; Wardlaw and Collinson, 

1977; this volume, Chapter D). The Murdock Mountain 

Formation is therefore Roadian to earliest Wordian in 

age (Early-Late Permian according to Furnish (1973) 

or Early Permian according to the U.S. Geological 

Survey) (fig. 6). 

5 
6 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

NEVADA 

Leach Mountains 

0 20 

L...L.....l 

KILOMETERS 

I 

I 

I • Montello 

I 

I 

UTAH 

Pilot Range 

FIGURE 4.-Location of the type section of the Murdock Mountain Formation in the Leach Mountains, 

Elko County, Nev. Contour interval 200 ft (61 m). Base from U.S. Geological Survey 1:24,000 

Loray (1967). 

The Murdock Mountain Formation is transitional in 

character between the equivalent Plympton Formation 

of west-central Utah and east-central Nevada and the 

Rex Chert Member of the Phosphoria Formation in 

northeastern Utah and southeastern Idaho. The M urdock Mountain Formation contains a lesser proportion 

of bedded chert than the Rex Chert Member to the 

north and a greater proportion of fine-grained sandstone and chert than the predominantly dolomitic 

Plympton Formation to the south. Much of the chert 

within the unit is secondary. 

REFERENCES CITED 

Furnish, W. M., 1973, Permian stage names, in Logan, A., and Hills, 

L., eds., The Permian and Triassic Systems and their mutual 

boundary: Canadian Society of Petroleum Geologists Memoir 2, 

p. 522-548. 

Wardlaw, B. R., 1977, Biostratigraphy and paleoecology of the 

Gerster Limestone (Permian) in Nevada and Utah: U.S. 

Geological Survey Open-File Report 77-470, 125 p. 

Wardlaw, B. R., and Collinson, J. W., 1977, Biostratigraphic zonation of the Park City Group: U.S. Geological Survey Open-File 

Report 77-853, 15 p. 
~~--L- -....£--- 15 

--=.t...~ 

...L.. ~ -L. 

..... · ..... 14 

13 

12 

11 

10 

9 

8 

7 

7 

7 

- 7 

- 7 

MURDOCK MOUNTAIN FORMATION 

GERSTER LIMESTONE 

MURDOCK MOUNTAIN FORMATION 

22. 

21. 

20. 

19. 

18. 

17. 

16. 

15. 

14. 

13. 

12. 

11. 

10. 

9. 

8. 

7. 

6. 

5. 

4. 

3. 

2. 

1. 

Sandy dolomite 

Dolomite with 20 percent light-gray chert 

Dolomite with 60 percent dark-gray chert 

Light-gray chert 

Lenticular dolomite between bands of dark-gray chert 

(60 percent), white chalcedony-filled vugs 

Sandy dolomite 

Dolomite, fossil hash, with 10 percent dark-gray chert, 

0.3-1.0-m beds separated by thin shaly layers 

Silty cherty dolomite 

Fine-grained sandstone with small-scale crossbedding 

Silty fine-grained dolomite with 60 percent irregular 

bands of dark-gray chert 

Dark-gray chert, irregularly banded with lenses of 

dolomite, fossil hash, with white chalcedony nodules, 

concretions of dark-gray chert around white 

chalcedony nucleus 

Fine-grained sandstone 

Cherty dolomite 

Dark-gray chert 

Dolomite with 50 percent dark-gray chert 

Dark-gray chert, 

Cherty siltstone 

Dark-gray chert 

Conglomerate 

bedded 

Silty limestone, fossiliferous horizon 

Cherty dolomite 

Cherty beds, poorly exposed 

Covered interval 

METERS 

100 

0 

MEADE PEAK PHOSPHORIA SHALE 

TONGUE OF THE PHOSPHORIA FORMATION 

FIGURE 5.-Columnar section of the Murdock Mountain Formation. 

7 
8 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

Subdivisions in use by 

Furnish (1973, fig. 1) U.S. Geological Survey 

~ERIES STAGE SERIES 

z CHANGHSINGIAN <( 

u: 

z -I 

c( ::J CHHIDRUAN 

~ :I: 

N 

a: 0 

w ARAKSIAN UPPER PERMIAN 

Cl. 

a: z 

<( AMARASSIAN w a: Cl. ::J Cl. -I CAPITANIAN ::::> <( 

0 

<( 

::J WORDIAN " 

z ROADIAN <( 

z ~ f/) 

c( z LEONARDIAN 

~ i= 

a: a: <( AKTASTINIAN LOWER PERMIAN w 

Cl. 

a: 

w z ~TERLITAMAKIAN 

~ <( 

ii: 

0 <( TASTUBIAN ...J ~ 

lil:: 

<( 

ASSELIAN f/) 

FIGURE G.-Subdivisions of the Permian. 
Stratigraphy of 

Park City Group Equivalents 

(Permian) in Southern Idaho, 

Northeastern Nevada, and 

Northwestern Utah 

ByBRUCER. WARDLAW, JAMESW. COLLINSON, andEDWINK. MAUGHAN 

STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND 

RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-C 
CONTENTS 

Page 

Abstract ---------------------------------------------------------------------------------------------------- 9 

Introduction ------------------------------------------------------------------------------------------------------- 9 

Stratigraphy of the western phosphate field------------------------------------------------------------·-- 10 

Stratigraphy of the east-central Nevada and adjacent Utah------------------------------------ 10 

Stratigraphy of northeastern Nevada, northwestern Utah, and southern Idaho----------------- 11 

Stratigraphic correlations ----------------------------------------------------------------------------------------- 11 

Interpretation -----------------·------------------------------------------------------------------------------------------ 14 

References cited -----------------------------------------------------------------------------------·------------------------ 16 

ILLUSTRATIONS 

Page 

FIGURE 7. Index map of area of investigation---------------------------------------------------- 9 

8. Diagram of formation and member relationships of the Park City Group 

and the Phosphoria and Park City Formation of Permian age---------------- 10 

9. Diagram of biostratigraphic zonation of Park City-Phosphoria 

equivalents -------------------------------------------------------------------------------------- 12 

10. Columnar sections of Park City-Phosphoria equivalents in Idaho, 

Nevada, and Utah ----------------------------------------------------------------------------- 13 

11. Fence diagram showing formational interrelationships of the Phosphoria 

and Park City Formations and the Park City Group in Idaho, 

Nevada, and Utah ------------------·----------·------------------------------------------ 14 

12. Isopach map of Park City-Phosphoria equivalents----------------------------- 15 

13. Map showing tectonic and rock-unit distribution of Permian Park City 

equivalents ---------------------------------------------------------------------------- 15 
STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND RELATED ROCKS, 

GREAT BASIN-ROCKY MOUNTAIN REGION 

STRATIGRAPHY OF PARK CITY GROUP EQUIVALENTS (PERMIAN) 

IN SOUTHERN IDAHO, NORTHEASTERN NEVADA, AND 

NORTHWESTERN UTAH 

By BRUCE R. WARDLAW, JAMES W. COLLINSON, and EDWIN K. MAUGHAN 

ABSTRACT 

The relationships of the Permian Park City Group to the 

Phosphoria and Park City Formations are clarified by the 

stratigraphy of four sections in northwestern Utah, northeastern 

Nevada, and southern Idaho. 

INTRODUCTION 

Biostratigraphic data confirm that the Park City 

Group and the Park City and Phosphoria Formations 

compose a heterogeneous body of closely related rocks 

of Roadian and Wordian Age (stages of Furnish, 1973) 

that once extended across the cratonic and miogeosynclinal areas of Utah and eastern Nevada. The Park 

City Group (Kaibab Limestone, Plympton Formation, 

and Gerster Limestone) of east-central Nevada and 

west-central Utah is correlated with the Phosphoria 

and Park City Formations of northeastern Utah, 

southwestern Wyoming, and southeastern Idaho, 

through the use of four key sections in the intervening 

area of northwestern Utah, northeastern Nevada, and 

southern Idaho (fig. 7). The three sections in the Terrace and Cedar Mountains (Utah) and the Leach Mountains (Nevada) are assigned to the Park City Group; 

the section in the Cassia Mountains (Idaho) belongs to 

the Phosphoria Formation. The Grandeur Tongue of 

the Park City Formation, which is equivalent to the 

Kaibab Limestone, is elevated to formation rank in the 

Cedar and Terrace Mountains. The Meade Peak Phosphatic Shale Member (locally a tongue in northeastern 

Nevada and northwestern Utah) of the Phosphoria 

Formation is a useful marker horizon over the entire 

region. Rocks transitional from the Plympton Formation to the Rex Chert Member of the Phosphoria Formation occur in the Leach and Terrace Mountains. The 

Gerster Limestone is most complete in the Leach 

Mountains; elsewhere biostratigraphic zones are beveled by Late Permian-Early Triassic erosion. 

42" 

40" 

39" 

Cassia 

Mountains 

Pequop 

Mountains 

NEVADA 

IDAHO 

Terrace 

Mountains 

0 

mining 

district 

112" 

UTAH 

1 00 KILOMETERS 

FIGURE 7.-Index map of area of investigation. 

9 
10 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

Isopachs of the Park City Group and its equivalents 

indicate that an east-trending axis of thinning in eastcentral Nevada and west-central Utah separates the 

depositional basin into two distinct structural lobes, 

one centered in west-central Utah and the other in 

northeast Nevada. Facies relationships suggest that 

these were not bathymetric basins; deeper water existed to the north in Idaho. A carbonate shelf deepening 

toward the chert and phosphatic-mudstone depositional areas in Idaho, extended across Utah to central 

Nevada during Roadian and Wordian time. A series of 

highlands or islands bordered the carbonate shelf 

along the Antler orogenic belt in central Nevada and 

served as source areas for sandstone and conglomerate. 

STRATIGRAPHY OF THE WESTERN PHOSPHATE 

FIELD 

The stratigraphy of the western phosphate field was 

revised by McKelvey and others (1956, 1959) to reflect 

the complex relationships between Permian chertmudstone-phosphorite facies, carbonate facies, and 

sandstone facies. The name Phosphoria Formation was 

retained for phosphorite, phosphatic mudstone, carbonaceous mudstone, and chert in southeastern Idaho 

and adjacent areas. The Park City Formation was retained for predominantly carbonate rock sequences 

such as in the type area near Park City, Utah. The 

name Shedhorn Sandstone was introduced for 

equivalent rocks in northwestern Wyoming and adjacent parts of Montana. The Phosphoria and Park City 

Formations were subdivided into members. When a 

member of one formation was identified within the sequence of the other formation, it was called a tongue of 

the former. 

The Phosphoria Formation was originally named by 

Richards and Mansfield (1912, p. 684-689) for the 

sequence at Phosphoria Gulch, near Montpelier, Bear 

Lake County, Idaho. McKelvey and others (1959) 

recognized the following members (in approximate 

ascending order): lower chert member, Meade Peak 

Phosphatic Shale Member, Rex Chert Member, cherty 

shale member, Retort Phosphatic Shale Member, and 

Tosi Chert Member. Not all of these members occur at 

the type section, and some are lateral equivalents of 

one another. These relationships are shown diagrammatically in figure 8. 

The Park City Formation, named by Boutwell (1907, 

p. 443-446), was subdivided by McKelvey and others 

(1959) into three members (in ascending order): 

Grandeur Member, Franson Member, and Ervay Carbonate Rock Member. All of these members are 

predominantly carbonate, and they are separated by 

tongues of the Phosphoria Formation. 

PHOSPHORIA FORMATION 

AND PARK CITY GROUP 

IN NORTHEAST NEVADA 

AND NORTHWEST UTAH 

Gerster 

Limestone3 

Rex 

Chert1 

Kaibab 

Limestone3 

Grandeur 

Formation3 

PHOSPHORIA AND PARK 

CITY FORMATIONS IN 

IDAHO AND WYOMING 

Retort1 

Grandeur2 

1Member of the Phosphoria Formation. 

2Member of the Park City Formation. 

3Formation of the Park City Group. 

FIGURE B.-Diagram of formation and member relationships of the 

Park City Group and the Phosphoria and Park City Formations of 

Permian age. 

The Shedhorn Sandstone (McKelvey and others, 

1959) is mainly to the north of the region considered 

here. 

STRATIGRAPHY OF EAST-CENTRAL NEVADA 

AND ADJACENT UTAH 

Hose and Repenning (1959, p. 2178) raised the name 

Park City in rank to Park City Group for rocks that 

comprised (in ascending order) the Kaibab Limestone, 

Plympton Formation, and Gerster Limestone in the 

Confusion Range, Utah. The formations were also 

recognized in east-central Nevada (Steele, 1960). 

The Kaibab Limestone in east-central Nevada and 

adjacent Utah is a 75-m- to 150-m-thick unit of massive 

cliff-forming limestone and cherty dolomite. The formation in this region is equivalent to the lower part of 

the Kaibab Limestone and possibly to the Lower Permian Toroweap Formation at the type locality of these 

formations in the Grand Canyon area as described by 

Noble (1928) (Baird and Collinson, 1975). 
STRATIGRAPHY OF THE PARK CITY EQUIVALENTS 11 

The Plympton Formation was named by Hose and 

Repenning (1959, p. 2181-2184) in the Confusion 

Range for a 212-m-thick sequence of dolomite and 

chert, containing minor amounts of pelletal phosphate, 

chert-pebble conglomerate, carbonate "breccia," sandstone, siltstone, and gypsum. Several authors have 

speculated that phosphatic beds near the base of the 

Plympton represent a tongue of the Meade Peak 

Phosphatic Shale Member (Cheney and others, 1956, 

p. 1716-1719; Hodgkinson, 1961, p. 180; Bissell, 1962, 

p. 241; Roberts and others, 1965, p. 1942-1943). 

The Gerster Limestone was named by Nolan (1935, 

p. 39) for a thin-bedded sandy and shaly limestone sequence exposed at Gerster Gulch in the Gold Hill mining district, Utah. A richly fossiliferous limestone over 

its regional extent, the Gerster Limestone varies from 

43 m to 341m in thickness in east-central Nevada and 

adjacent Utah (Wardlaw and Collinson, 1978). 

STRATIGRAPHY OF NORTHEASTERN NEVADA, 

NORTHWESTERN UTAH, AND SOUTHERN IDAHO 

The detailed stratigraphy of four measured sections 

is shown in figure 9. The sequences in the Leach Mountains, Terrace Mountains, and Cedar Mountains are 

pretlominantly carbonate and are referable to the Park 

City Group. The Grandeur is recognized in the Terrace 

and Cedar Mountains as part of the Park City Group 

and is elevated to formational status. Its correlative 

in the Leach Mountains is the Kaibab Limestone. The 

sequence in the Cassia Mountains belongs to the 

Phosphoria Formation. The thicknesses of these 

measured sections are reliable, except perhaps for the 

lower part of the section in the Terrace Mountains 

where the Grandeur Formation and the Murdock 

Mountain Formation, a new name (this volume, 

Chapter B), are poorly exposed and complexly faulted. 

The Grandeur Formation forms the base of the Park 

City Group in northwestern Utah and is composed of 

carbonate, which is mostly cherty dolomite and has 

lesser amounts of bioclastic limestone, chert, 

mudstone, and sandstone. Although the Grandeur is 

lithologically similar to the Kaibab Limestone which 

occurs in the Leach Mountains, it is more heterogeneous, containing sandstone, siltstone, phosphorite, and chert. In the Leach Mountains the base of the 

Park City Group consists of a thin sequence of Kaibab 

Limestone overlying the Lower Permian Arcturus Formation or Loray Formation of Steele (1960). Most 

subsequent workers have included the Loray in the 

Grandeur. The most common fossils are crinoid and 

bryozoan fragments and whole brachiopods. 

The Meade Peak Phosphatic Shale Tongue of the 

Phosphoria Formation overlies the Grandeur Formation. It is characterized by dark carbonaceous 

mudstone and thin beds of phosphorite and dark 

bioclastic limestone. Snails are the most abundant 

fossils; brachiopods, conodonts, and impressions of 

ammonoids also occur. 

The greatest facies changes in this region occur in 

the interval above the Meade Peak Phosphatic Shale 

Tongue and below the Gerster Limestone. In the Cedar 

Mountains a sequence of dolomite, chert, mudstone, 

and sparse limestone is assigned to the Plympton Formation. To the north in the Cassia Mountains, this 

interval is occupied by massive chert of the Rex Chert 

Member of the Phosphoria Formation. In the Leach 

and Terrace Mountains, a unit that seems to be transitional between the Plympton Formation and the Rex 

Chert Member consists of chert, cherty dolomite, 

limestone, and sandstone; it is called the Murdock 

Mountain Formation. The sandstone in the Cassia and 

Leach Mountains is unlike the Shedhorn Sandstone 

and was probably derived from the same westerly 

source as the Permian Edna Mountain Formation of 

northeastern Nevada (Roberts and others, 1965, 

p. 1941). 

The Gerster Limestone forms the upper unit of the 

Park City Group throughout its regional extent. It 

does not occur with the Phosphoria Formation in the 

Cassia Mountains, because the upper part of the sequence has been removed by erosion. The Gerster 

Limestone is a cherty bioclastic limestone containing 

minor beds of chert, dolomite, and siltstone. Crinoid 

and bryozoan fragments and, commonly, silicified 

whole brachiopods make up much of the rock. The 

lithology and fauna of the Gerster Limestone are 

similar to those of the Franson Member of the Park 

City Formation. 

Two intervals of secondary chert replacing carbonate within the Gerster Limestone in both the Leach 

and Terrace Mountains sections represent tongues of 

the Murdock Mountain lithology. In the upper part of 

the Gerster in the Leach Mountains is a thick interval 

of alternating limestone and secondary chert replacing 

limestone, which could be interpreted as another 

tongue of the Murdock Mountain Formation but is 

here kept in the Gerster. In the middle of this interval 

is a platy limestone that may be equivalent to the 

Retort Phosphatic Shale of the Phosphoria Formation. 

STRATIGRAPHIC CORRELATIONS 

Figure 10 shows the application of the biostratigraphic zones of Wardlaw and Collinson (1977; this 

volume, Chapter D). The four columnar sections of the 

present study are correlated with the Fort Douglas 

(Cheney and others, 1953) and Sublette Range (Smart 

and others, 1954) sections summarized by McKelvey 

and others (1959) and with the Gerster Gulch (Gold 
12 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

LEACH 

MOUNTAINS 

Plympton 

Formation3 

Rex1 

Meade Peak 

(upper)l 

Franson 

(lower)2 

1Member of the Phosphoria Formation. 

2Member of the Park City Formation. 

3Formation of the Park City Group. 

FIGURE 9.-Biostratigraphic zonation of Park City-Phosphoria equivalents. The zones are: 1, Peniculauris; 2, Thamnosia; 3, Kuvelousia; and 

4, Yakovlevia. 

Hill District) and southern Pequop Mountains sections 

of Wardlaw and Collinson (1977). The Penicularis Zone 

is modified from Zone 2 of Wardlaw and Collinson 

(1977), which is based on brachiopods and conodonts. 

The Thamnosia, Kuvelousia, and Yakovlevia Zones are 

equivalent to the Thamnosia depressa (Zone 4), 

Kuvelousia leptosa (Zone 5), and Yakovlevia multistriata-Neogondolella bitteri (Zone 6) Zones. The Penicularis Zone is interpreted by Wardlaw and Collinson 

(1977) to be Roadian. The Meade Peak is also Roadian 

(Furnish, 1973, p. 534) on the basis of ammonoid 

faunas. The Thamnosia, Kuvelousia, and Yakovlevia 

Zones are Wordian. These stage names follow the 

usage of Furnish (1973). His Roadian and Wordian are 

assigned to the Early Permian Epoch by the U.S. 

Geological Survey. 

Interpretation of the biostratigraphic zones as 

relative time lines clarifies formational interrelationships (fig. 11). This is a reasonable interpretation 

because the zones are widely distributed and are not 

limited to a single facies. These correlations are further 

supported by lithostratigraphic continuity of such 

widespread units as the Meade Peak Phosphatic Shale 

Member. 

Biostratigraphic data confirm the following temporal relationships: (1) The Kaibab Limestone of northeastern and east-central Nevada and adjacent Utah, 

the Grandeur Formation of northwestern Utah, and 

the Grandeur Member of the Park City Formation in 

northeastern Utah are equivalent. (2) A tongue of the 

Meade Peak Phosphatic Shale Member is widespread 

and occurs between the base of the Plympton Forma-
STRATIGRAPHY OF THE PARK CITY EQUIVALENTS 

LEACH 

MOUNTAINS 

EXPLANATION . 6 d Dmwoo y 

fl_,_ ~'~l~l Limestone 

f~..L='=="==:I Dolomite 

1---=- =I Siltstone and shale 

I : · · · · ::I Sandstone 

1--•.1 Chert 

I o ~ 0 I Conglomerate 

I • • • I Phosphorite 

~Limy 

Dolomitic 

- k'2''! I Cherty 

I :f /.i,. I Sandy 

I J ).I Silty 

._ __ _.1 Covered interval 

-=:::::::;....-Fault-Arrows 

show relative 

movement 

Murdock 

Mountain 

Formation 

1Member of the Phosphoria Formation. 

2M ember of the Park City Formation. 

FIGURE 10.-Columnar sections of Park City-Phosphoria equivalents in Idaho, Nevada, and Utah. Quotation 

marks indicate undescribed genera. 

13 
14 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

L----, 

I 

\ 7 

?-- -- ( ~ l 1 J SUBLETIE ~--{__ I RANGE 

0 100 KILOMffiRS - ---"' 9 ~ Che 

s 

Meade Peak1 

1Member of the Phosphoria Formation. 

2Member of the Park City Formation. 3Formation of the Park City Group. 

FORT 

DOUGLAS 

4 

SOUTHERN 

PEQUOP 

MOUNTAINS 

7 

CONFUSION 

RANGE 

1 

METERS 

[ 

FIGURE ll.-Fence diagram showing formational interrelationships of the Phosphoria and Park City 

Formations and the Park City Group in Idaho, Nevada, and Utah. 

tion and the top of the Grandeur. The lower part of the 

Plympton Formation in the Confusion Range and the 

Meade Peak Phosphatic Shale Tongue are equivalent; 

therefore, the lower Plympton and the Meade Peak 

Member of the Phosphoria Formation are equivalent. 

(3) The Rex Chert Member of the Phosphoria Formation, the major part of the Plympton Formation, and 

the major part of the Murdock Mountain Formation in 

the Leach and Terrace Mountains are equivalent. (4) 

The uppermost part of the Plympton Formation, 

which contains sparse beds of fossiliferous limestone in 

east-central Nevada, is equivalent to the lowermost 

part of the Gerster Limestone in the Leach and Terrace 

Mountains. These limestone beds in the upper Plympton contain specimens of Thamnosia (Wardlaw and 

Collinson, 1977) and probably represent tongues of the 

Gerster Limestone from the north. (5) The uppermost 

Plympton Formation and much of the Gerster 

Limestone are equivalent to the Franson Member of 

the Park City Formation. (6) Late Permian-Early 

Triassic erosion beveled the Gerster Limestone into 

the Yakovlevia Zone in the Cedar Mountains and 

greatly limited the upper part of the Franson in the 

Fort Douglas section. (7) Where the Gerster Limestone 

is most complete, such as in the Leach and Terrace 

Mountains and in the Confusion Range, the upper part 

may be equivalent to or younger than the Ervay Carbonate Rock Member of the Park City Formation. 

INTERPRETATION 

The isopach map (fig. 12) indicates thinning along an 

east-west axis passing near the southern Pequop 

Mountains and Gerster Gulch (the Gold Hill mining 

district). This axis is projected eastward into an area 

where data are sparse, because trends of similar highs 

are recorded for Pennsylvanian and older Permian 

rocks in this region, such as the Cortez-Uinta axis 

(Roberts and others, 1965, p. 1937; Marcantel, 1975, p. 

2082). Although this thinning is partly due to postdepositional erosion, the thinning of biostratigraphic 

zones in the Gerster Limestone in the southern Pequop 

Mountains and Gold Hill mining district indicates that 

this axis was active by Wordian time (Wardlaw and 

Collinson, 1978). 

The axis of thinning appears to separate the depositional basin into two distinct structural lobes, one 

centered in west-central Utah and the other in north-
STRATIGRAPHY OF THE PARK CITY EQUIVALENTS 15 

114° 

IDAHO 

42" 

0 50 100 KILOMETERS 

FIGURE 12.-Isopach map of Park City-Phosphoria equivalents. 

Thicknesses (in meters) based on data from Cheney and others 

(1953); Smart and others (1954); Sheldon (1963); Baker and others 

11 7" 

z 

0 

(.!:) 

IJJ IDAHO 

111° 

Kaibab 

Limestone 

CRATON 

~---- --------

ARIZONA 

100 200 KILOMETERS 

(1949); Welsh (1972); Crosby (1959); Wardlaw and Collinson 35" L---.L-----~-...L.-- ------'------' 

(1978); Sheldon and others (1953); Sheldon and others (1954); 

McKelvey and others (1953); Schell and Gere (1964); and this 

study. Isopach queried where data sparse. 

eastern Nevada (fig. 12). Areas of greatest thickness 

probably do not coincide with bathymetric centers of 

the basin. McKelvey and others (1959, p. 5-6) interpreted the chert, phosphorite, and mudstone of the 

Phosphoria Formation as representing the deeper 

water facies, and they placed the deepest part of the 

basin in east-central Idaho. The thinning of the sequence to the north into Idaho, as indicated by the 

isopachs (fig. 12), probably reflects slower depositional 

rates in deeper water. 

The deeper water area of central Idaho was bordered 

by a carbonate shelf that extended from the cratonic 

area of eastern Utah to the west margin of the 

miogeosyncline in central Nevada (fig. 13). The Park 

City Formation and the partly equivalent Kaibab 

Limestone were deposited on the craton. The much 

thicker Park City Group is found in the miogeosycline. 

An increasingly greater proportion of chert and 

phosphatic mudstone in the Park City Group as it is 

traced northward from east-central Nevada and adjaPhosphorite, chert, 

and mudstone 

EXPLANATION 

c:=J 

Carbonate 

~ 

~ 

Sandstone and 

conglomerate 

FIGURE 13.-Tectonic and rock-unit distribution of Permian Park 

City equivalents (modified from Roberts and others, 1965, p. 1941). 

cent Utah to Idaho suggests gradual deepening of this 

shelf. 

The miogeosyncline was apparently separated from 

the eugeosyncline by a series of highlands or islands 

along the Antler orogenic belt. In north-central 

Nevada the Park City Group grades into sandstone 

and calcareous sandstone of the Edna Mountain Formation of Wordian Age (Silberling and Roberts, 1962, 

p. 16). Conodonts of Roadian Age (Zone 3 of Wardlaw 

and Collinson, 1977) were found in a limestone sample 

from high in the conglomeratic Permian Garden Valley 

Formation at Twin Springs Hills, 40 km west of 

Eureka, Nev. (collected by Kent Chamberlain, Univ. 

Nevada, Las Vegas). Farther south in the Candelaria 

Hills, Esmeralda County, and Toiyabe Range, northern Nye County, the sandy and conglomeratic Permian 
16 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

Diablo Formation contains a Wordian brachiopod 

fauna (Silberling and Roberts, 1962, p. 28). 

REFERENCES CITED 

Baird, M., and Collinson, J. W., 1975, Conodont biostratigraphy of 

the Kaibab and Plympton Formations: Geological Society of 

America Abstracts with Programs, v. 7, no. 6, p. 716. 

Baker, A. A., Huddle, J . W., and Kinney, D. M., 1949, Paleozoic 

geology of north and west sides of Uinta basin, Utah: American 

Association of Petroleum Geologists Bulletin, v. 33, no. 7, 

p. 1161-1197. 

Bissell, H. J ., 1962, Pennsylvanian and Permian rocks of Cordilleran 

Area, in Branson, C. C., ed., Pennsylvanian system in the 

United States-A symposium: Tulsa, American Association of 

Petroleum Geologists, p. 188 263. 

Boutwell, J. M., 1907, Stratigraphy and structure of the Park City 

mining district, Utah: Journal of Geology, v. 15, p. 434-458. 

Cheney, T. M., Smart, R. A., Waring, R. G., and Warner, M.A., 

1953, Stratigraphic sections of the Phosphoria formation in 

Utah, 1949- 51: U.S. Geological Survey Circular 306,40 p. 

Cheney, T. M., McKelvey, V. E., and Gere, W. C., 1956, Fusulinidbearing rocks in Sublett Range, Southern Idaho: American 

Association of Petroleum Geologists Bulletin, v. 40, no. 7, 

p.1716-1719. 

Crosby, G. W., 1959, Geology of south Pavant Range, Millard and 

Sevier Counties, Utah: Brigham Young University Research 

Studies, Geology Series, v. 6, no. 3, p. 1-59. 

Furnish, W. M., 1973, Permian stage names, in Logan, A., and Hills, 

L., eds., The Permian and Triassic Systems and their mutual 

boundary: Canadian Society of Petroleum Geologists Memoir 2, 

p. 511-548. 

Hodgkinson, K. A., 1961, Permian stratigraphy of northeastern 

Nevada and northwestern Utah: Brigham Young University 

Geology Studies, v. 8, p. 167-196. 

Hose, R. K., and Repenning, C. A., 1959, Stratigraphy of Pennsylvanian, Permian, and Lower Triassic rocks of the Confusion 

Range, west-central Utah: American Association of Petroleum 

Geologists Bulletin, v. 43, no. 9, p. 2167-2196. 

Marcantel, J. B., 1965, Late Pennsylvanian and Early Permian 

sedimentation in northeast Nevada: American Association of 

Petroleum Geologists Bulletin, v. 59, no. 11, p. 2079-2098. 

McKelvey, V. E., Armstrong, E. C., Gulbrandsen, R. A., and 

Campbell, R. M., 1953, Stratigraphic sections of the Phosphoria 

formation in Idaho, 1947-1948, part 2: U.S. Geological Survey 

Circular 301, 58 p. 

McKelvey, V. E., Williams, J. S., Sheldon, R. P., Cressman, E. R., 

Cheney, T.M., and Swanson, R. W., 1956, Summary description 

of Phosphoria, Park City, and Shedhorn formations in western 

phosphate field: American Association of Petroleum Geologists 

Bulletin, v. 40, no. 2, p. 2826-2863. 

___ 1959, The Phosphoria, Park City, and Shedhorn formations 

in the western phosphate field: U.S. Geological Survey Professional Paper 313-A, 47 p. 

Noble, L. F., 1928, A section of the Kaibab limestone in Kaibab 

Gulch, Utah: U.S. Geological Survey Professional Paper 150, 

p. 41- 60. 

Nolan, T. B., 1935, The Gold Hill mining district, Utah: U.S. 

Geological Survey Professional Paper 177, 172 p. 

Richards, R. W., and Mansfield, G. R., 1912, The Bannock overthrust; a major fault in southeastern Idaho and northwestern 

Utah: Journal of Geology, v. 20, p. 681-709. 

Roberts, R. J., Crittenden, M.D., Jr., Tooker, E. W., Morris, H. T., 

Hose, R. K., and Cheney, T. M., 1965, Pennsylvanian and Permian basins in northwestern Utah, northeastern Nevada and 

south-central Idaho: American Association of Petroleum 

Geologists Bulletin, v. 49, no. 11, p.1926-1956. 

Schell, E. M., and Gere, W. C., 1964, Preliminary report on the 

phosphate deposits and stratigraphy of Permian rocks in Dry 

Bread Hollow, Weber County, Utah: U.S. Geological Survey 

Open-File Report, 15 p. 

Sheldon, R. P., 1963, Physical stratigraphy and mineral resources of 

Permian rocks in western Wyoming: U.S. Geological Survey 

Professional Paper 313-B, p. 49-273. 

Sheldon, R. P., Cressman, E. R., Carswell, L. D., and Smart, R. A., 

1954, Stratigraphic sections of the Phosphoria formation in 

Wyoming, 1952: U.S. Geological Survey Circular 325, 24 p. 

Sheldon, R. P., Waring, R. G., Warner, M. A., and Smart, R. A., 

1953, Stratigraphic sections of the Phosphoria formation in 

Wyoming, 1949-50: U.S. Geological Survey Circular 307, 45 p. 

Silberling, N.J., and Roberts, R. J., 1962, Pre-Tertiary stratigraphy 

and structure of northwestern Nevada: Geological Society of 

America Special Paper 72, 58 p. 

Smart, R. A., Waring, R. G., Cheney, T. M., and Sheldon, R. P., 

1954, Stratigraphic sections of the Phosphoria formation in 

Idaho, 1950-51: U.S. Geological Survey Circular 327, 22 p. 

Steele, G., 1960, Pennsylvanian-Permian stratigraphy of eastcentral Nevada and adjacent Utah, in Geology of east-central 

Nevada: Intermountain Association of Petroleum Geologists, 

11th Annual Field Conference, 1960, Guidebook, p. 91-113. 

Wardlaw, B. R., and Collinson, J. W., 1977, Biostratigraphic zonation of the Park City Group: U.S. Geological Survey Open-File 

Report 77-853, 15 p. 

___ 1978, Stratigraphic relationships of the Park City Group 

(Permian) in eastern Nevada and western Utah: American 

Association of Petroleum Geologists Bulletin, v. 62, no. 7, 

p. 1171-1184. 

Welsh, J. E., 1972, Upper Paleozoic stratigraphy, plateau- basin 

and range transition zone, central Utah: Utah Geological 

Association Publication 2, p. 13-20. 
Biostratigraphic Zonation of the 

Park City Group 

By BRUCE R. WARDLAW and JAMES W. COLLINSON 

STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND 

RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1163-D 
CONTENTS 

Page 

Abstract ------------------------------------------------------------------------------------------------------------------------------------- 17 

In trodu c ti on --------------------------------------------------------------------------------------..0..--------------------------------------- 1 7 

Peniculauris ivesi-Neostreptognathodus prayi Zone-------------------------------------------------------------- 17 

Peniculauris bassi-N eos treptognathodus s ulcoplicatus Zone ------------------------------------------------ 19 

Peniculauris bassi-Neostreptognathodus sp. C Zone--------------------------------------------------------------- 20 

Tham nos ia de pres sa Zone ---------------------------------------------------------------------------------------------------------- 20 

K u v e lo usia le p to sa Zone-------------------------------------------------------------------------------------------------------------- 20 

Y akovlevia multis triata-Neogondolella bi tteri Zone ----------------------------------------------------------------- 20 

References cited ------------------------------------------------------------------------------------------------------------------------- 22 

ILLUSTRATIONS 

Page 

FIGURE 14. Generalized range chart of brachiopod and conodont species from the Park 

City Group ---------------------------------------------------------------------------------------------- 18 

15. Chart of distribution of biostratigraphic zones in the Park City Group------- 21 
STUDIES OF THE PERMIAN PHOSPHORIA FORMATION AND RELATED ROCKS, 

GREAT BASIN-ROCKY MOUNTAIN REGION 

BIOSTRATIGRAPHIC ZONATION OF THE PARK CITY GROUP 

By BRUCE R. WARDLAW and JAMES W. COLLINSON 

ABSTRACT 

Five biostratigraphic zones based on the distribution of 

brachiopods and conodonts are proposed for the Park City Group. 

They are: the Peniculauris ivesi-Neostreptognathodus prayi Zone, 

the Peniculauris bassi-Neostreptognathodus sulcoplicatus Zone, the 

Peniculauris bassi-Neostreptognathodus sp. C Zone, the Thamnosia 

depressa Zone, and the Yakovlevia multistriata-Neogondolella bitteri Zone. They range in age from Leonardian to Wordian. 

INTRODUCTION 

The biostratigraphic zonation proposed here is based 

on the ranges of brachiopod and conodont species (fig. 

14). The distribution of the biostratigraphic zones in 

the Park City Group is shown in figure 15. Samples for 

conodonts were collected at intervals of 3-5m where 

practical. Large samples for brachiopods were collected at intervals usually averaging 7-10 m, for the 

purpose of etching to obtain the silicified material. 

Crackouts were collected throughout the section and 

the data were augmented by field identifications. The 

lower part of the sequence is best represented by conodonts and the upper part by brachiopods; the zonation is slanted accordingly. Because our data are from 

a relatively small region, fossil ranges partly reflect 

basin-wide facies changes. These ranges will probably 

expand as data from other regions are added. The 

zones are Oppel-zones (Hedberg, 1976), with the exception of Zones 1 and 3, which are based on ranges of conodonts. 

The time-stratigraphic subdivision of the Permian 

System proposed by Furnish (1973) is followed. Taxa 

without specific names are designated by letters of the 

alphabet and conform to the usage of these names in 

the theses of Wardlaw (1974), Baird (1975), and Marcantel (1975). 

PENICULA URIS IVESI-NEOSTREPTOGNATHODUS 

PRA YI ZONE (1) 

Based on the range on the conodont N. pray~ this 

zone is similar to the Neostreptognathodus 

sulcoplicatus-N. prayi Assemblage Zone of Behnken 

(1975, p. 292-293). In emending N. sulcoplicatus 

(Youngquist, Hawley, and Miller) Behnken (1975, p. 

211-212; pl. 1, figs. 2, 4) included what we regard as 

Neostreptognathodus sp. D from the Pequop Formation of Steele (1960) and the Arcturus Formation, 

thereby erroneously extending the range of N. 

sulcoplicatus to the Leonardian Stage of Furnish 

(1973). 

Examples of N. prayi Behnken occur in the lower 

two-thirds of the Kaibab sections in eastern Nevada 

and western Utah, except in the Confusion Range section, where they occur in the lower half of the formation. In addition to finding N. prayi in the Kaibab 

Limestone, Behnken (1975, p. 287) reported it from the 

upper part of the Arcturus and Pequop Formations, 

which are older than the Kaibab. Baird (1975) foundN. 

prayi in the Toroweap Formation of southern Utah. In 

West Texas, Behnken (1975, p. 293) described N. prayi 

from the Bone Spring Limestone, Victorio Peak 

Limestone, and from the basal part of the overlying 

Cutoff Shale. He implied that N. prayi ranges from the 

upper Leonardian into the lower Wordian in age. This 

Wordian age assignment is apparently based on a 

report by Bissell (1964, p. 616-617, 620, 624) of 

Guadalupian ammonoids in the underlying Loray Formation, which has since proved to be erroneous (W. M. 

Furnish, oral commun., 1976). The occurrence of N. 

prayi in the Bone Spring and Victorio Peak 

Limestones strongly suggests a late Leonardian age 

for this zone. 

17 
18 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

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Neogondolella bitter/ 

Zone (6) 

Kuvelousia /eptosa 

Zone (5) 

Thamnosla depressa 

Zone (4) 

"barren interval" 

Penlcu/aurls bassiN eostreptognathodus 

sp. C Zone (3) 

Penicu/aurls bassi· 

Neostreptognathodus 

sulcop/icatus 

Zone (2) 

Penicu/aurls ivesl· 

Neostreptognathodus 

pray/ Zone (1) 

2 The U.S. Geological Survey does not recognize the Roadian-Wordian boundary as the Lower Permian-Upper Permian boundary as some American 

workers do. The Wordian-Capitanian boundary is recognized as the division. 
BIOSTRATOGRAPHIC ZONATION OF THE PARK CITY GROUP 19 

Behnken (1975, p. 290) indicated that Neogondolella 

idahoensis occurs with N. prayi in the West Texas sequence. A broken fragment identified by Baird (1975) 

as N. cf. N. idahoensis was found in the upper part of 

the N. prayi Zone in eastern Nevada. The brachiopod 

Peniculauris ivesi (Newberry) is common in the 

Toroweap Formation in southern Utah and northern 

Arizona. It sporadically occurs elsewhere from the upper part of the Pequop and Loray Formations in 

Nevada and one occurrence in the lowermost part of 

the Kaibab at Spruce Mountain in Nevada. All occurrences fall within the range of N. prayi. 

PENICULA URIS BASSI-NEOSTREPTOGNA THODUS 

SULCOPLICATUS ZONE (2) 

The base of this zone is marked by the lowest occurrence of N. sulcoplicatus (Youngquist, Hawley, and 

Miller), and Neostreptognathodus sp. B (Baird, 1975). 

The top of this zone is defined by the lowest occurrence 

of Neostreptognathodus sp. C (Baird, 1975). The N. 

sulcoplicatus Zone occurs in the upper Kaibab Limestone and presumably the lower part of the Plympton 

Formation of eastern Nevada and western Utah and in 

the lower two-thirds of the Kaibab at its type section in 

southern Utah. Youngquist, Hawley, and Miller (1951) 

first described this species from the lower Phosphoria 

Formation in southeastern Idaho. Clark and Ethington (1962) described N. sulcoplicatus along with Xaniognathus abstractus (Clark and Ethington) from the 

Meade Peak Member of the Phosphoria Formation in 

southeastern Idaho and Wyoming. Neogondolella 

idahoensis was also described from these rocks by 

Youngquist, Hawley, and Miller (1951) and Clark and 

Ethington (1962). 

An important component of the Meade Peak conodont fauna, Neogondolella serrata (Youngquist, 

Hawley, and Miller), has not been reported from 

eastern Nevada or western Utah, probably because the 

phosphatic shale facies has not been adequately sampled. We, nevertheless, believe that the N. sulcoplicatus Zone in eastern Nevada and western Utah is 

equivalent to the Meade Peak fauna, which Furnish 

(1973) assigned to the Roadian Stage. This age assignment eliminates the problem posed by Behnken (1975, 

p. 290) that conodont species of "Roadian age" in 

Texas range into strata of ·"Wordian age" in Nevada. 

The brachiopods Peniculauris bassi (McKee), 

Rugatia occidentalis (Newberry), Kozlowskia sp., 

Meekella sp., Megousia eucharis (Girty), and 

Neophricadothyris sp. A are abundant in this zone. 

From the many sections of the Permian of the western 

United States examined by the authors, this seems to 

be the highest occurrence of Meekella and Kozlowskia 

in the West. They are widespread, occurring 

throughout the Grandeur Member of the Park City 

Formation in Montana and Wyoming and in the 

Kaibab Limestone in Arizona and Utah, as well as in 

the Concha Limestone in Arizona. Kozlowskia is strictly a Pennsylvanian to Lower Permian form. P. bass~ R. 

occidentalis, and Neophricadothyris are the dominant 

FIGURE 14 (left).-Generalized range chart of brachiopod and conodont species from the Park City Group. 

1. Peniculauris ivesi (Newberryl 25. Bathymyonia sp. A 46. Phrenophoria sp. C 67. Neostreptognathodus sp. D 

2. Lissochonetes sp. A 26. Derbyia sulca (Bransonl 47. Petasmatherus sp. A 68. Neostreptognathodus clinei 

3. Peniculauris bassi (McKeel 27. Xestotrema pulchrum (Meekl 48. Rostranteris sp. Behnken 

4. Derbyia sp. A 28. Hustedia sp. A 49. Girtyella? 69. Xaniognathus abstractus (Clark 

5. Rhynchopora taylori Girty 29. Spiri{erellina sp. A 50. Heterelasma sp. A and Ethingtonl 

6. Neophricadothyris sp. A 30. Thamnosia sp. A 51. Plectelasma sp. A 70. Ellisonia festiva (Bender and Stop7. Megousia eucharis (Girtyl 31. "Echinauris" subhorrida (Meekl 52. Echinalosia sp. A pell 

8. Meekella sp. 32. Kuvelousia leptosa Waterhouse 53. Waagenites sp. B 71. Anchignathodus sp. A 9. Echinauris sp. A 33. Waagenites sp. A 54. Odontospirifer sp. A 72. Neogondolella idahoensis (Young- 10. Quadrochonetes sp. A 34. Dyoros sp. A 55. Cenorhynchia sp. B quist, Hawley, and Millerl 11. Kozlowskia sp. 35. Dielasma cf. D. phosphoriensis 56. Plectelasma sp. B 73. Neostreptognathodus sp. B 12. "Cancrinella" sp. Branson 57. Hemiptychina sp. A 74. Neostreptognathodus sulcopli- 13. Rugatia occidentalis (Newberryl 36. Cleiothyridina sp. A 58. Quadrochonetes sp. B catus (Youngquist, Hawley, and 14. Composita cf. C. parva Branson 37. Bathymyonia nevadensis (Meekl 59. Timaniella "pseudocameratus" Millerl 15. Waagenoconcha sp. 38. Composita mira Girty 60. Yakovleuia multistriata (Meekl 75. Xaniognathus tribulosus (Clark 16. Neospiri{er sp. 39. Ctenalosia {ixata Cooper and 61. Liosotella delicatula Dunbar and Ethingtonl 17. Spiriferellina? Stehli 18. Cenorhynchia sp. 62. Heteralosia sp. 76. Neostreptognathodus sp. C 

19. Phrenophoria sp. A 40. Cleiothyridina sp. B 63. Kochiproductus sp. 77. Neospathodus arcucristatus Clark 

20. Liosotella? 41. "Grandaurispina" sp. A 64. "Grandaurispina" cf. "G. " arctica and Behnken 

21. "Echinosteges" 42. Sphenosteges hispidus (Girtyl (W aterhousel 78. Ellisonia sp. A 

22. Sphenalosia sp. A 43. Phrenophoria sp. B 65. Dielasma spatulatum Girty 79. Neogondolella bitteri (Kozurl 

23. Dielasma sp. A 44. Cenorhynchia sp. A 66. Neostreptognathodus prayi 80. Neospathodus divergens (Bender 

24. Thamnosia depressa (Cooperl 45. Spiriferella scobina (Meekl Behnken and Stoppell 
20 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

elements of the fauna of the Grandeur but also carry 

through to the Meade Peak. Megousia eucharis is common in the Grandeur and Meade Peak. The highest occurrence of Peniculauris and Rugatia in the West 

Texas Permian is Roadian. 

PENICULA URIS BASSI-NEOSTREPTOGNA THODUS 

SP. C ZONE (3) 

The base of this zone is determined by the first occurrence of Neostreptognathodus sp. C (Baird, 1975). 

Examples of this form dominate the conodont fauna of 

the upper 45 m of the type section of the Kaibab 

Limestone in southern Utah (Noble, 1928) and also occur in the lower part of the Plympton Formation in the 

Confusion Range in western Utah. The upper limit of 

this zone is not well defined, because the top of the 

Kaibab in southern Utah is truncated by an unconformity; and in western Utah the lower part of the 

Plympton is sparsely fossiliferous. For example, 

Behnken (1975, p. 293) reported a "very meager" conodont assemblage from the lower part of the Plympton 

Formation including Neostreptognathodus clinei 

(Behnken). Further sampling, particularly in the 

Phosphoria and related rocks, is likely to narrow this 

gap. Brachiopods are poorly preserved in this zone. 

Peniculauris is the only identifiable brachiopod found 

so far from the lower Plympton. The Kaibab 

brachiopod assemblage and the conodont faunas 

typified by species of Neostreptognathodus became extinct at this time. The presence of Peniculauris and the 

age of the overlying brachiopod faunas indicate a 

Roadian Age for this zone. The upper boundary probably marks the Artinskian-Guadalupian boundary. 

THAMNOSIA DEPRESSA ZONE (4) 

This zone is based on the nearly coincident ranges of 

Thamnosia depressa (Cooper) and Bathymyonia sp. A. 

T. depressa occurs in the limestone tongues of the upper part of the Plympton Formation, the limestone 

tongues in the Rex Chert Member of the Phosphoria 

Formation, and at El Antimonio, Mexico. Sphenalosia 

and "Echinauris" subhorrida (Meek), Derbyia sulca 

(Branson), Xestotrema pulchrum (Meek), and Hustedia 

sp. A start in this zone. The highest occurrence of 

Rugatia occidentalis is in the upper Plympton Formation. Rugatia, which is more common in the Great 

Basin than in West Texas, appears to have a longer 

range here than in West Texas, ranging into the lower 

Wordian equivalents. 

This zone is more or less equivalent to the 

Neospathodus arcucristatus "Fauna" of Clark and 

Behnken (1971) from the upper Plympton Formation 

and basal Gerster Limestone at Palomino Ridge 

(Phalen Butte). The upper Plympton Formation contains a sparse conodont assemblage including N. arcucristatus, Ellisonia sp. A (E. Marcantel, 1975), and 

Anchignathodus sp. A (E. Marcantel, 1975=A. 

minutus of Behnken, 1975). 

Yochelson andFraser (1973) reported an unusually 

well preserved molluscan faunule from unit 5 of the 

Plympton Formation in the southern Pequop Mountains. Silicified pelecypods from approximately the 

same horizon in the Spruce Mountain section are probably examples of the genus Schizodus (D. W. Boyd, 

written commun., 1975). 

KUVELOUSIA LEPTOSA ZONE (5) 

The base of this zone is determined by the first occurrence of Kuvelousia leptosa Waterhouse, 

Ctenalosia fixata Cooper and Stehli, W aagenites sp. A, 

and several other Gerster brachiopods. The range of K. 

leptosa is commonly equivalent to this zone. The zone 

ends with the first occurrence of several upper Gerster 

brachiopods such as Timaniella ''pseudocameratus. '' 

K. leptosa is widespread, occurring in all Gerster sections, the upper limestones of the Rex Chert Member 

of the Phosphoria Formation, the Franson Member of 

the Park City Formation, the Diablo Formation at 

Candelaria, Nev., and the lower part of the Seven 

Devils Group and related rocks, Oregon and Idaho. 

Kuvelousia is strictly an Upper Permian genus. Conodonts are rare in this zone. Only Neospathodus arcucristatus and Ellisonia sp. A occur. The range of Anchignathodus sp. A ends below this zone in unit 5 of 

the Plympton and the range of Neogondolella bitteri 

starts in the upper Gerster in the zone above. 

YAKOVLEVIA MULTISTRIATA-NEOGONDOLELLA 

BITTER/ ZONE (6) 

The base of this zone is determined by the first occurrence of the brachiopods Timaniella "pseudocameratus, "Petasmatherus sp. A, Heterelasma sp. A, 

Echinalosia sp. A, Odontospirifer sp. A, Plectelasma 

sp. A and B, Hemiptychina sp. A, and others. The 

range of the widespread and abundant Yakovlevia 

multistriata (Meek) is totally inclusive within this 

zone. Y. multistriata occurs elsewhere in the Edna 

Mountain Formation, Nevada, and the upper part of 

the Franson and the lower part of the Ervay Members 

of the Park City Formation in Wyoming. T. 

"pseudocameratus" is also widespread, occurring in 

the Edna Mountain Formation, in the Diablo Forma-
Medicine 2 

40 

~ H 

.ELY 

0 

I I 

BIOSTRATOGRAPHIC ZONATION OF THE PARK CITY GROUP 

METERS 

0 

100 

3 

4 200 

5 

~ Limestone 

~ Dolomite 

~ .. Chert 

~ Siltstone and fine- . grained sandstone < 

0 9 < Conglomerate > 0 

w 

z ~ . Silty 

~ Cherty 

50 KILOMETERS 

I 

6 

5 

4 

EXPLANATION 

~~·jJ Dolomitic 

D Covered 

7 

Confusion 

Range 

CD 

c 

.s 

, 

CD 

E 

::::i 

lD 

e 

CD 

C) 

c 

0 

:; . E 

0 

LL 

c 

0 

Q. 

E 

>-

0:: 

a. 

:I 

0 

" >-

0 

.II: 

as 

Cl.. 

MP Meade Peak Phosphatic Shale Member 

of Phosphoria Formation 

----- Zone boundary 

- -- Formation contact 

- -- Formation and zone boundary 

- Unconformity 

~ Part of sequence with no fossil data 

3 Brachiopod-conodont zones 

FIGURE 15.-Distribution of biostratigraphic zones in the Park City Group. 

21 
22 PHOSPHORIA FORMATION AND RELATED ROCKS, GREAT BASIN-ROCKY MOUNTAIN REGION 

tion at Candelaria, Nev., at Taylorsville, Calif., and in 

the Retort Phosphatic Shale Member of the Phosphoria Formation in Wyoming. In West Texas, 

Yakovlevia occurs in Roadian and Wordian beds; 

Petasmatherus occurs in Lower Permian and Wordian 

beds of Furnish (1973); Echinalosia occurs only in 

Wordian beds. 

The name N. bitteri was propsed by Kozur (1975, 

p. 19-20) for the form assigned by Clark and Behnken 

(1971, p. 424, 434-435) to Gondolella rosenkrantzi 

Bender and Stoppel. 

This zone is similar to the ''Gondolella rosenkrantzi'' 

Zone plus the Neospathodus divergens "Fauna" of 

Clark and Behnken (1971, p. 428). Behnken (1975, 

p. 293) later combined the Neospathodus arcucristatus 

"Fauna" with the "Gondolella rosenkrantzi" Zone, 

because he found these two forms occurring together 

throughout the central Butte Mountains (30-mile 

Ranch) sequence. He suggested that the stratigraphic 

separation of these two forms at the Phalen Butte 

(Polomino Ridge) section was "ecologic" rather than 

biostratigraphic. We agree that the distribution of 

these forms is in part facies controlled, but the 

biostratigraphic overlap is slight in all of our sections, 

including the one from the central Butte Mountains. 

A few examples of N. divergens (Bender and Stoppel) 

were found near the top of our sections in the central 

Butte Mountains, Cherry Creek Range, Palomino 

Ridge and, possibly, the Medicine Range (Marcantel, 

1975). (See fig. 15.) This is the same interval that 

Behnken (1975, p. 293) included in the Neogondolella 

''rosenkrantzi''-Neospathodus divergens Assemblage 

Zone. He also reported the brachiopod Xestotrema 

pulchrum (Meek) and elements of the conodont 

Xaniognathus tribulosus (Clark and Ethington). These 

conodonts in addition to the many species of 

brachiopod are also common in our section of the upper 

part of the Gerster Limestone, but N. divergens was 

not abundant enough in our collections to recognize 

this as a separate zone. 

REFERENCES CITED 

Baird, M. R., 1975, Conodont biostratigraphy of the Kaibab Formation, eastern Nevada and west-central Utah: Columbus, Ohio, 

The Ohio State University, M.S. thesis, 71 p. 

Behnken, F. H., 1975, Leonardian and Guadalupian (Permian) conodont biostratigraphy in western and southwestern United 

States: Journal of Paleontology, v. 49, no. 2, p. 284-315. 

Bissell, H. J., 1964, Ely, Arcturus, and Park City Groups (Pennsylvanian-Permian) in eastern Nevada and western Utah: 

American Association of Petroleum Geologists Bulletin, v. 48, 

p. 565-636. 

Clark, D. L., and Behnken, F. H. 1971, Conodonts and 

biostratigraphy of the Permian: Geological Society of America 

Memoir 127, p. 415-439. 

Clark, D. L., and Ethington, R. L., 1962, Survey of Permian conodonts in western North America: Brigham Young University 

Geology Studies, v. 9, p. 102-114. 

Furnish, W. M., 1973, Permian stage names, in Logan, A., and 

Rilles, L., eds., The Permian and Triassic Systems and their 

mutual boundary: Canadian Society of Petroleum Geologists 

Memoir 2, p. 522-548. 

Hedberg, H. D., ed., 1975, International stratigraphic guide-a 

guide to stratigraphic classification, terminology, and procedure: New York, John Wiley, 200 p. 

Kozur, H., 1975, Beitrage zur conodontenfauna des Perm: Geol. 

Palaont. mitt. Innsbruck, v. 5, no. 4, p. 1-44. 

Marcantel, E. L., 1975, Conodont biostratigraphy and sedimentary 

petrology of the Gerster Formation (Guadalupian) in eastcentral Nevada and west-central Utah: Columbus, Ohio, The 

Ohio State University, Ph. D. dissertation, 203 p. 

Noble, L. F., 1928, A section of the Kaibab Limestone in Kaibab 

Gulch, Utah: U.S. Geological Survey Professional Paper 150-C, 

p.41-60. 

Steele, G., 1960, Pennsylvanian-Permian stratigraphy of eastcentral Nevada and adjacent Utah, in Geology of east-central 

Nevada: Intermountain Association of Petroleum Geologists, 

11th Annual Field Conference, Guidebook, p. 91-113. 

Wardlaw, B. R., 1974, The biostratigraphy and paleoecology of the 

Gerster Formation (Upper Permian) in Nevada and Utah: 

Cleveland, Ohio, Case Western Reserve University, Ph. D. 

dissertation, 215 p. 

Yochelson, E. L., and Fraser, G. D., 1973, Interpretation of depositional environment in the Plympton Formation (Permian), 

southern Pequop Mountains, Nevada, from physical 

stratigraphy and a faunule: U.S. Geological Survey Journal of 

Research,v.1,no. 1,p.19-32. 

Youngquist, W. L., Hawley, R.W., and Miller, A. K., 1951, 

Phosphoria conodonts from southeastern Idaho: Journal of 

Paleontology, v. 25, no. 3, p. 356-364. 

* U.S. GOVERNMENT PRINTING OFFICE, 1979-677-129/20