Correlation of Permian and 

Pennsylvanian Sections 

Between Egan Range 

and Spring Mountains 

Nevada

By PATRICK J. BAROSH

CONTRIBUTIONS TO STRATIGRAPHY

GEOLOGICAL SURVEY BULLETIN 1254-1
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director

U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON : 1968

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

Washington, D.C. 20402 - Price 10 cents (paper cover)
CONTENTS

Page

Abstract________________________________________________________ I 1

Introduction_ _____________________________________________________ 1

Egan Range____________________________________________ 3

Spring Mountains.________________________________________________ 3

Correlation _______________________________________________________ 3

Comparative ages.________________________________________________ 6

Conclusions.___________________ _ ________________________________ 7

References cited_________________________________________________ 7

ILLUSTRATIONS

Page 

FIGURE 1. Index map showing location of Egan Range and Spring

Mountains ____________________________________________ 12

2. Chart showing correlation of Permian and Pennsylvanian

strata in the Egan Range and Spring Mountains..______ 5

in

CONTRIBUTIONS TO STRATIGRAPHY

CORRELATION OF PERMIAN AND PENNSYLVANIAN

SECTIONS BETWEEN THE EGAN RANGE AND SPRING

MOUNTAINS, NEVADA

By PATRICK J. BAROSH

ABSTRACT

The Permian and Pennsylvanian parts of the Bird Spring Formation near 

Lee Canyon in the northern Spring Mountains, northwest of Las Vegas, can be 

correlated with the Ely Limestone, lower and coralline members of the Riepe 

Spring Limestone of Steele (1960), the Rib Hill Sandstone, and the lower member 

of the Arcturus Formation of the central Egan Range, near Ely, on the basis 

of similarities in lithology, sequence, and assigned age.

The thick Lee Canyon sequence is a key section in the correlation of the Permian and Pennsylvanian strata of east-central and southern Nevada.

INTRODUCTION

Thick and widespread Permian and Pennsylvanian strata occur in 

east-central and southern Nevada but are present only as smaU thin 

remnants in the intervening area. The Permian rocks undergo considerable facies change along an east-west trend in east-central 

Nevada and adjacent Utah (Barosh, 1964, 1965) and, at places, are 

difficult to correlate between adjacent ranges. Facies changes within 

the Pennsylvanian rocks are less severe. Facies changes occur along 

an east-west trend in southern Nevada also.

The lack of significant intervening Permian and Pennsylvanian 

strata between east-central and southern Nevada and the facies 

changes within these regions rendered correlations between these 

regions tenuous at best. The striking similarities between the Permian 

and Pennsylvanian section near Lee Canyon in the northern part of 

the Spring Mountains, northwest of Las Vegas, and the section in 

the central part of the Egan Range, near Ely, provide an opportunity 

to place the regional correlation on a much firmer basis (fig. 1).

II
12 CONTRIBUTIONS TO STRATIGRAPHY

r~

,Elko

NEVADA

I oReno ^Eureka

>Ely

v Egan 

Range

V

*

N \

V

* Spring 

\ Mountains Lee Canyon

50 

I

100 MILES 

I

FIGURE 1. Index map showing location of Egan Range and 

Spring Mountains, Nev.
EGAN RANGE AND SPRING MOUNTAINS, NEVADA I 3

EGAN RANGE

The Permian and Pennsylvanian section in the Egan Range begins 

with the Pennsylvanian Ely Limestone, a cherty limestone sequence. 

Permian strata overlie the Ely along a disconformity marked by a 

very thin chert-pebble conglomerate. The basal Permian formation 

is the Riepe Spring Limestone of Steele (1960). The Riepe Spring 

Limestone of the Egan Range is composed of (1) a lower member of 

limestone, limy dolomite, and a thin basal chert breccia that marks 

the Pennsylvanian-Permian unconformity; (2) a coralline member, 

which characterizes the formation; and (3) an upper member of cherty 

limestone (Barosh, 1964). The lower member thickens southward 

through the central Egan Range, whereas the upper member thins 

southward. The Riepe Spring is overlain by the Rib Hill Sandstone 

(Riepetown Sandstone of Steele, 1960), a buff to red calcareous siltstone with subordinate carbonate rocks. It underlies the Arcturus 

Formation, divisible into a lower member composed of alternating 

medium-bedded limestone and buff siltstone, and an upper member 

composed of alternating thin-bedded limestone and buff to red siltstone and minor gypsum. The Arcturus is succeeded by the Kaibab 

Limestone, a massive bioclastic limestone (Langenheim and others, 

1960; Barosh, 1964).

SPRING MOUNTAINS

In the northern Spring Mountains, Permian and Pennsylvanian 

strata, in addition to some Mississippian rocks, form the Bird Spring 

Formation. Hewett (1931) briefly described the formation from exposures in the Bird Spring Range, south of the Spring Mountains, and 

Longwell and Dunbar (1936) later divided it into five members. The 

most complete and continuous section occurs near Lee Canyon and is 

more than 7,000 feet thick (Rich, 1959, 1961, 1963; Longwell and 

others, 1965). The formation consists of limestone and subordinate 

siltstone and some shale and sandstone at the base.

CORRELATION

The Bird Spring Formation was traversed near Lee Canyon along 

the line of section measured by Rich (1959, 1961, 1963), and the strata 

are here discussed in terms of units of his measured section. Rich 

apparently measured the section in pieces as his unit numbers are not 

in sequence. Rich's (1959, 1961) correlation of the Lee Canyon section 

with the unit numbers of Longwell and Dunbar (1936) is given as a 

reference.

The basal sequence of sandstone, limestone, and shale, units 2-9 

(fig. 2), is Mississippian in age and correlates with the thicker Chainman Shale, which underlies the Pennsylvanian Ely Limestone in the
14 CONTRIBUTIONS TO STRATIGRAPHY

Egan Range (MacKenzie Gordon, Jr., and F. G. Poole, written 

commun., 1966; Webster and Lane, 1967; fig. 2). This sequence forms 

the lower part of the Indian Springs Member of Longwell and Dunbar 

(1936) or the Indian Springs Formation as restricted by Webster and 

Lane (1967).

The overlying limestone sequence, units 10-298, is similar to and 

correlates with the Ely Limestone in the Egan Range. The sequence 

contains the same types of cherty limestone and megafossils. Chaetetes 

and Syringopora biostromes occur sporadically in both sections, 

although Syringopora is more abundant in the Spring Mountains. This 

sequence corresponds to the upper part of the Indian Springs Member 

and all of member 2 of Longwell and Dunbar (Rich, 1959, p. 9, 12).

The cherty limestone sequence is succeeded by a less cherty sequence, units 136A-13A, which is capped by a coralline limestone unit, 

units 12A-2A. The coralline limestone is the same in appearance as 

the coralline member of the Riepe Spring Limestone in the Egan 

Range. Both this unit and the coralline member contain numerous 

Lithostrotion-type corals, commonly recrystallized. These two sequences correspond to member 3 of Longwell and Dunbar (Rich, 1959, 

p. 9, 12).

The thickness of the lower member equivalent represented in the 

Lee Canyon section is not precisely known; a sequence of cherty and 

noncherty limestone and silty limestone lies between the coralline 

member and the definite Ely-like lithology, but no distinct lithologic 

break was seen in the interval. No chert breccia such as is present along 

the contact in the Egan Range was found. The chert content of the 

limestone gradually decreases upward. The ledge-forming nature of 

several of the limestone units in the middle of the slope is more characteristic of the Ely than of the lower member, but below the ledges are 

some light- to medium-gray-weathering silty dolomitic limestone 

units, which are similar to some in the lower member.

Apparently strata in the lower part of the interval between the 

definite Ely-like rocks and the coralline member in the Spring Mountains are absent from the central Egan Range but are present, in 

part, in the southern Egan Range. Rich (1959, 1961) found Upper 

Pennsylvanian rocks and a transitional Pennsylvanian-Permian 

boundary in the Lee Canyon section. In the southern Egan Range, 

R. C. Douglass (in U.S. Geol. Survey, 1962, p. A42) studied Upper 

Pennsylvanian rocks below an unconformity, unlike the relations in 

the central Egan Range, where Wolfcamp rocks of the Riepe Spring 

disconformably overlie Middle Pennsylvanian strata of the Ely 

Limestone (fig. 2). The Upper Pennsylvanian rocks near Lee Canyon 

apparently form a transitional sequence between rocks equivalent 

to the Ely and the lower member of the Riepe Spring of the Egan
EGAN RANGE AND SPRING MOUNTAINS, NEVADA 15

CO 

CO

(I)

a.

EGAN RANGE

CENTRAL PART

(Barosh, 1964; Langenheim and

others, 1960; and Steele, 1960)

Kaibab Limestone 

100 ft +

Arcturus 

Formation 

3,350 ft

Upper 

member 

1,800 ft

Lower 

member 

1,450ft

Rib Hill Sandstone

(Riepetown Sandstone

of Steele, 1960)

1,000-1,200 ft

Riepe

Spring

Limestone

of Steele

'(1960)

250-435 ft

Upper member 

16-150 ft

Coralline

member

130-228 ft

Lower

member

75-150 ft

Ely

Limestone 

2,500-3,000 ft

Chainman

Shale 

1,000± ft

SPRING MOUNTAINS

NORTHERN' PART

NEAR LEE CANYON

(Thicknesses of intervals and

unit numbers at contacts from

Rich, 1959, 1961)

360B

270B

1,393ft

269 B

2,494 ft

1A

2A

12A

95ft

13A

494-870 ft

90A

91A 

136A

376ft

298

2,215-2,591 ft

10

100ft

(£) 

(S3

Q. 

CO

FIGURE 2. Correlation of Permian and Pennsylvanian strata in the Egan 

Range and the Spring Mountains, Nev.
I 6 CONTRIBUTIONS TO STRATIGRAPHY

Range. The equivalent stratigraphic position of the unconformity 

would probably lie within the Upper Pennsylvanian rocks above the 

Ely-like lithology, that is, within the 376 feet of strata between units 

298 and 90A. This makes the equivalent of the lower member of 

the Riepe Spring between 494 and 870 feet thick at Lee Canyon, 

which is much thicker than in the Egan Range. Correspondingly, 

the Ely equivalent would be between 2,215 and 2,591 feet thick 

(fig. 2). The equivalent of the upper member of the Riepe Spring was 

not seen near Lee Canyon and must be very thin or missing there.

Overlying the Riepe Spring equivalent at Lee Canyon is a thick 

sequence of buff calcareous siltstone, silty limestone and limestone, 

units 1A-269B, similar to the equivalent Rib Hill Sandstone in the 

Egan Range. This sequence corresponds approximately to member 4 

of Longwell and Dunbar (Rich, 1959, p. 9, 12). The base of the sequence is buff rather than red, as it generally is in the Egan Range 

and the sequence as a whole has a greater lime content. The Rib Hill 

thickens southward through the central Egan Range (Barosh, 1964) 

and is considerably thicker in the Spring Mountains than in the Egan 

Range. Rich (1963, p. 1679) recognized the equivalency of the stratigraphic position of this part of the section to the Rib Hill (Riepetown 

Sandstone of Steele, 1960).

The Rib Hill equivalent is succeeded by a limestone sequence that 

continues to the top of the measured section, units 270B-360B, which 

is very similar to the lower member of the Arcturus Formation in the 

Egan Range. Unit 270B at the base of the Arcturus equivalent in the 

Lee Canyon section, forms a bluff capped by a zone of abundant 

fasciculate corals as it does in the central Egan Range. The lower 

member corresponds approximately to member 5 of Longwell and 

Dunbar (Rich, 1959, p. 12). The section is terminated at the top by 

faults and erosion (Rich, 1959, 1961, 1963) and apparently does not 

extend as high as the upper member of the Arcturus Formation.

COMPARATIVE AGES

A comparison of the indicated ages of the strata in the Spring 

Mountains (Rich, 1959, 1961; Christy, 1958) and the central Egan 

Range (Barosh, 1964; Langenheim and others, 1960; Wilson and 

Langenheim, 1962) agrees well with the lithologic correlations.

The Mississippian-Pennsylvanian boundary is approximately at 

the base of the Ely in both areas. The Pennsylvanian-Permian 

boundary differs in the two areas due to the lack of Upper Pennsylvanian rocks in the central Egan Range, but is consistent with the 

lithologic correlations. The Wolfcamp-Leonard boundary lies in 

the same general position in both areas. Near Lee Canyon it is considered to fall within 242 feet below and 237 feet above the base of
EGAN RANGE AND SPRING MOUNTAINS, NEVADA I 7

the Arcturus equivalent, between units 243B and 292B (Christy, 

1958; Rich, 1959, 1961). In the Egan Range the boundary is considered to be within the lower member of the Arcturus, possibly as 

low as 130 feet above the base (Wilson and Langenheim, 1962; 

Barosh, 1964).

CONCLUSIONS

The Permian and Pennsylvanian strata of the Bird Spring Formation near Lee Canyon in the northern Spring Mountains can be 

correlated with the Ely Limestone, lower and coralline members of 

the Riepe Spring Limestone, the Rib Hill Sandstone and the lower 

member of the Arcturus Formation of the central Egan Range on the 

basis of similarities in lithology, sequence, and assigned age. The main 

differences in the stratigraphic units at Lee Canyon, the absence of 

the upper member, greatly increased thickness of lower member of the 

Riepe Spring Limestone, and probable absence of the disconformity 

are predictable from trends of changes in the Egan Range.

The well-studied Lee Canyon section could serve as a standard 

section in the correlation of the Permian and Pennsylvanian strata of 

east-central and southern Nevada if the other Permian and Pennsylvanian sections in southern Nevada are keyed to the Lee Canyon 

section.

Pennsylvanian and especially Permian sedimentation was apparently more uniform along the strike of facies in east-central and 

southern Nevada than has been previously described.

The Bird Spring Formation has been elevated to group status 

farther east by Langenheim, Carss, Kennerly, McCutcheon, and 

Waines (1962). If the Bird Spring is raised to group rank in the Spring 

Mountains, the stratigraphic terminology from the central Egan 

Range can be considered for the Permian and Pennsylvanian strata, 

and proliferation of formational names thus be avoided.

REFERENCES CITED

Barosh, P. J., 1964, Lower Permian stratigraphy of east-central Nevada and

adjacent Utah: U.S. Geol. Survey open-file report, 144 p. 

 1965, Permian stratigraphy of east-central Nevada, in Abstracts for 1964:

Geol. Soc. America Spec. Paper 82, p. 317-318. 

Christy, R. B., 1958, Some Permian fusulinid faunas near Lee Canyon, Clark

County, Nevada: Illinois Univ. unpub. M.S. thesis, 39 p. 

Hewett, D. F., 1931, Geology and ore deposits of the Goodsprings quadrangle,

Nevada: U.S. Geol. Survey Prof. Paper 162, 172 p. 

Langenheim, R. L., Jr., Barr, F. T., Shank, S. E., Stensaas, L. J., and Wilson,

E. C., 1960, Preliminary report on the geology of the Ely No. 3 quadrangle,

White Pine County, Nevada: Intermountain Assoc. Petroleum Geologists

llth Ann. Field Conf. Guidebook, p. 148-156.
I 8 CONTRIBUTIONS TO STRATIGRAPHY

Langenheim, R. L., Jr., Carss, B. W., Kennerly, J. B., McCutcheon, V. A., and 

Waines, R. H., 1962, Paleozoic section in Arrow Canyon Range, Clark 

County, Nevada: Am. Assoc. Petroleum Geologists Bull., v. 46, p. 592-609.

Longwell, C. R., and Dunbar, C. D., 1936, Problems of Pennsylvanian-Perrman 

boundary in southern Nevada: Am. Assoc. Petroleum Geologists Bull., v. 20, 

p.1198-1207.

Longwell, C. R., Pampeyan, E. H., Bower, Ben, and Roberts, R. J., 1965, Geology 

and mineral deposits of Clark County, Nevada: Nevada Bur. Mines Bull. 62, 

218 p.

Rich, Mark, 1959, Stratigraphic section and fusulinids of the Bird Spring Formation near Lee Canyon, Clark County, Nevada: Illinois Univ., unpub. Ph.D. 

dissertation, 181 p.

 1961, Stratigraphic section and fusulinids of the Bird Spring Formation 

near Lee Canyon, Clark County, Nevada: Jour. Paleontology, v. 35, p. 

1159-1180.

1963, Petrographic analysis of Bird Spring Group (Carboniferous-Permian)

near Lee Canyon, Clark County, Nevada: Am. Assoc. Petroleum Geologists

Bull., v. 47, p. 1657-1681. 

Steele, Grant, 1960, Pennsylvanian-Permian stratigraphy of east-central Nevada

and adjacent Utah: Intermountain Assoc. Petroleum Geologists llth Ann.

Field Conf. Guidebook, p. 91-113. 

U.S. Geological Survey, 1962, Synopsis of geologic, hydrologic, and topographic

results: U.S. Geol. Survey Prof. Paper 450-A, 257 p. 

Webster, G. D., and Lane, N. G., 1967, Mississippian-Pennsylvanian boundary

in southern Nevada, in Essays in paleontology and stratigraphy (Raymond C.

Moore Commemorative Volume): Kansas Univ. Dept. Geology Spec. Pub. 2,

p. 503-522. 

Wilson, E. C., and Langenheim, R. L., Jr., 1962, Rugose and tabulate corals from

Permian rocks in the Ely quadrangle, White Pine County, Nevada: Jour.

Paleontology, v. 36, p. 495-520.