The lyanbito Member (A New 

Stratigraphic Unit) of the 

Jurassic Entrada Sandstone, 

Gallup-Grants Area, New Mexico

GEOLOGICAL SURVEY BULLETIN 1395-D

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The lyanbito Member (A New 

Stratigraphic Unit) of the 

Jurassic Entrada Sandstone, 

Gallup-Grants Area, New Mexico

By MORRIS W. GREEN

CONTRIBUTIONS TO STRATIGRAPHY

GEOLOGICAL SURVEY BULLETIN 1395-D

Description of a new Stratigraphic unit 

and redefinition of stratigraphy along the 

Wingate cliffs, McKinley and Valencia 

Counties, New Mexico

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1974
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

V. E. McKelvey, Director

Library of Congress Cataloging in Publication Data

Green, Morris W.

The lyanbito Member (a new stratigraphic unit) of the Jurassic Entrada Sandstone,

Gallup-Grants area, New Mexico

(Contributions to Stratigraphy) (Geological Survey Bulletin 1395-D) 

Bibliography: p. 

Supt. of Docs. No.: 119.3:1395-D

1. Geology, Stratigraphic-Jurassic. 2. Geology-New Mexico-Gallup region.

I. Title. II. Series. III. Series: United States Geological Survey Bulletin 1395-D. 

QE75.B9 no. 1395-D [QE681] 557.3' 08s [551.7'6l 74-17432

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

Washington, D. C. 20402 - Price 45 cents (paper cover)

Stock Number 2401-02571
CONTENTS

	Page

Abstract................................................................. Dl

Introduction ............................................................. 1

Type locality ............................................................ 3

Lithology, origin, and thickness ........................................... 5

Lower and upper contacts ................................................. 8

Age and previous correlations ............................................. 9

References cited .......................................................... 12

ILLUSTRATIONS

FIGURE 1. Map of Gallup-Grants area, showing outcrop of the Entrada Sandstone D2

2. Restored diagrammatic cross section showing general east-west relations

of the Entrada Sandstone and adjacent rocks..................... 4

3. Map showing location and access route to the type locality and

measured section of the lyanbito Member of the Entrada Sandstone 6

TABLE

Page

TABLE 1. Nomenclature for the stratigraphic interval between the Chinle Formation and Todilto Limestone in the Gallup-Grants area ............ D10

m

CONTRIBUTIONS TO STRATIGRAPHY

THE IYANBITO MEMBER 

(A NEW STRATIGRAPHIC UNIT) OF THE

JURASSIC ENTRADA SANDSTONE, 

GALLUP-GRANTS AREA, NEW MEXICO

By MORRIS W. GREEN

ABSTRACT

In the Gallup-Grants area of New Mexico, a sandstone and siltstone sequence lying unconformably above the Chinle Formation of Late Triassic age and conformably below the 

middle siltstone member of the Entrada Sandstone of Late Jurassic age is here named the 

lyanbito Member of the Entrada Sandstone. Previously, the lyanbito interval was 

thought to be separated unconformably from the overlying members of the Entrada 

Sandstone; thus, it had been correlated with the Lukachukai Member of the Wingate 

Sandstone of Late Triassic age. Assignment of the lyanbito as a member of the Entrada is 

here made for three reasons:

1. The contact between the lyanbito and the overlying middle siltstone member is conformable throughout the area and is gradational at most places, indicating that 

deposition was continuous.

2. The base of the lyanbito Member is marked by a laterally persistent erosional unconformity. Absence of an unconformity at the top of the lyanbito therefore indicates 

that the unconformity at the lower contact is the boundary between Triassic and 

Jurassic rocks in the Gallup-Grants area.

3. The lithology and the mode and environments of deposition of the lyanbito Member 

are closely related to those of the overlying members of the Entrada and are in contrast to those of the underlying Chinle Formation.

INTRODUCTION

A continental red-beds unit ranging in thickness from 12 to 44.2 m (40 

to 145 ft) and composed mainly of reddish-orange sandstone and 

reddish-brown sandy siltstone is well exposed at the base of the 

Wingate cliffs east of Gallup in McKinley County, N. Mex. The unit 

crops out eastward from Gallup to the vicinity of Grants in Valencia 

County (fig. 1). Throughout the area the unit lies unconformably above 

either the Owl Rock Member or the Petrified Forest Member of the Chinle 

Formation of Late Triassic age and conformably below the middle 

siltstone member of the Entrada Sandstone of Late Jurassic age. The 

unit is herein named the lyanbito (I-yan ' -bito) Member and assigned

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D2 CONTRIBUTIONS TO STRATIGRAPHY

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IYANBITO MEMBER, ENTRADA SANDSTONE, NEW MEXICO D3

to the Entrada Sandstone of Late Jurassic age. The lyanbito is the 

lowermost of three members of the Entrada Sandstone recognized in 

the Gallup-Grants area (fig. 2).

Previously, the lyanbito Member interval had been recognized as the 

Lukachukai Member of the Wingate Sandstone of Late Triassic age 

(Harshbarger and others, 1957, p. 8-12). The name Lukachukai 

Member of the Wingate Sandstone is here abandoned in the GallupGrants area.

This report is based on geologic mapping and related Stratigraphic 

studies which began in 1967 in the southern part of the San Juan Basin. 

These studies have been carried out in conjunction with uranium 

resource investigations in the San Juan mineral belt by the U.S. 

Geological Survey.

The author is grateful to L. C. Craig, C. H. Maxwell, R. B. 

O'Sullivan, C. T. Pierson, G. N. Pipiringos, J. F. Robertson, and J. D. 

Strobell, Jr., of the U.S. Geological Survey for their help on local and 

regional stratigraphy during the course of several field conferences in 

the San Juan Basin and adjacent areas. The author particularly thanks 

C. T. Pierson and J. F. Robertson for their continued support and 

cooperation during field and office studies.

TYPE LOCALITY

The name lyanbito means "Buffalo Springs" and is derived from the 

small Navajo Indian village located near the base of the Wingate cliffs 

in the Pinedale 7 J/2-minute quadrangle approximately 19 km (about 12 

mi) east of Gallup in McKinley County. The type locality is in the 

Church Rock 7 Vz -minute quadrangle in the NWV4 sec. 15 (unsurveyed), 

T. 15 N., R. 16 W. The site of the type locality is in the northeast 

quarter of the Fort Wingate Military Reservation (old boundary, as 

shown in fig. 3). The locality is 4.42 km (2.75 mi) N. 76°30' W. of lyanbito and 2.54 km (1.58 mi) N. 37° E. of Wingate Station. Access thereto 

is by way of Wingate Station. (See road shown leading northeast from 

Wingate Station on the map, fig. 3.) In 1971, the railway station house 

which marked the site of Wingate Station near the Atchinson, Topeka, 

and Sante Fe Railway was demolished; the station house was approximately 105 m (about 350 ft) north of the intersection of New Mexico Highway 400 and Interstate 40 (fig. 3).

Stratigraphic section measured and described at the type locality of the lyanbito Member 

of the Entrada Sandstone on July 21, 1971 Equivalent

Entrada Sandstone (Jurassic): Meters feet 

Middle siltstone member: Not measured; contact with lyanbito

Member conformable, 

lyanbito Member:

16. Sandstone, moderate-reddish-orange (IQR 6/6); high-angle 

crossbedded; medium- to fine grained, well sorted, subrounded to well rounded, friable; mainly clear iron-stained 

quartz with minor dark accessory minerals; contains large 

amount of milky-white chert.......................... 5.79 19.0
D4 CONTRIBUTIONS TO STRATIGRAPHY

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IYANBITO MEMBER, ENTRADA SANDSTONE, NEW MEXICO D5

Stratigraphic section measured and described at the type locality of the lyanbito Member 

of the Entrada Sandstone on July 21, 1971 Con.

Equivalent 

n x i n , , ,-, . v Meters feet Entrada Sandstone (Jurassic) _ Con. 

lyanbito Member Con.

15. Claystone and siltstone, dark-reddish-brown (10/2 3/4); flat

lens-shaped bed; laterally discontinuous ............... .03 .1

14. Sandstone, moderate-reddish-orange (10/2 6/6), massive to 

crossbedded, fine to very fine grained, well-sorted; subrounded to well-rounded grains ....................... 2.13 7.0

13. Sandy siltstone, moderate-reddish-orange (10/2 5/6), massive 

to flat bedded; calcareous locally; similar to middle 

siltstone member; polygonal mudcracks on upper bedding 

surface ............................................. 5.18 17.0

12. Claystone and siltstone; same as unit 15................. .1 .3

11. Sandstone, pale-yellowish-orange (10Y72 8/6); upper few centimeters "bleached" greenish-gray (5GV8/1); crossbedded, 

fine grained, well sorted; subrounded to well-rounded 

grains; friable; calcareous locally; some silty zones and 

stringer; white chert abundant ....................... .61 2.0

10. Claystone and siltstone; same as unit 15 ................. .1 .3

9. Sandstone; same as unit 11............................. 1.22 4.0

8. Siltstone, reddish-brown (10/2 6/4), massive; calcite cemented

along tower surface .................................. 1.83 6.0

7. Sandstone, moderate-reddish-orange (10/2 5/6), crossbedded, 

medium- to fine-grained, well-sorted; subrounded to wellrounded grains of white, pink, clear, yellow, brown, and 

black quartz. Crossbeds dip an average of 20° SW...... 3.05 10.0

6. Sandstone; same as unit 11............................. 3.05 10.0

5. Sandy siltstone; same as unit 13 ........................ 2.44 8.0

4. Sandstone; same as unit 7 .............................. 2.13 7.0

3. Claystone and siltstone; same as unit 15................. .03 .1

2. Sandstone; same as unit 7 .............................. 10.21 33.5

1. Sandstone, yellowish-gray (5V8/1), grayish-red (5/2 4/2), and 

moderate reddish-orange (10/2 7/6), massive to 

crossbedded; coarse to fine grained, with pebbles and 

granules as much as 6 mm (about Vi in.) across of white, 

black, clear, yellowish-green, gray, and pink quartz. Unit 

fills mudcracks as much as 1.2 m (4 ft) deep at the top of the 

underlying Owl Rock Member of the Chinle Formation . 0.3 1.0 

Total thickness of the lyanbito Member ............. 38.2 125.3

Chinle Formation (Triassic):

Owl Rock Member: not measured; contact with overlying lyanbito 

Member unconformable.

LITHOLOGY, ORIGIN, AND THICKNESS

Throughout the area the lyanbito is composed dominantly of reddishorange (1QR 5/6) crossbedded sandstone. In the western part of the area, 

where the lyanbito is thickest, reddish-brown (107? 6/4) sandy siltstone 

is interbedded with the sandstone in the upper part of the member. 

Locally, a few very thin beds of dark-reddish-brown (1QR 3/4) clay stone 

are interbedded with the siltstone. The lyanbito Member is friable and 

tends to weather to slopes and mounds at the base of the cliff carved in
D6 CONTRIBUTIONS TO STRATIGRAPHY

108°32'30" 32' 108°31'30' R. 16 W.

Site of \Wingate

tion house 

6740// ^^ \

I I I I I

1 MILE

J

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0 .5 1 KILOMETRE 

CONTOUR INTERVAL 40 FEET

FIGURE 3. Map showing location and access route for the type locality of the lyanbito 

Member of the Entrada Sandstone. Base from U.S. Geological Survey Church Rock 

quadrangle, 1:24,000, 1963.
IYANBITO MEMBER, ENTRADA SANDSTONE, NEW MEXICO D7

the overlying members of the Entrada Sandstone. The member lies on a 

dip slope formed by the more resistant limestone ledges in the underlying Owl Rock Member of the Chinle.

The lyanbito Member is composed mainly of clear iron-stained 

quartz and minor amounts of feldspar and black accessory minerals. 

Milky-white chert grains are distinctive components. Grain size ranges 

from coarse to very fine, although most grains are medium to fine. The 

grains are well sorted, well rounded, and poorly cemented with calcium 

carbonate and iron oxide. Concentrations of white chert grains are distributed along crossbed laminations and in lenses scattered throughout 

the lyanbito Member. These white chert grains also occur in the overlying members of the Entrada Sandstone. Pebbles and granules of white, 

red, and black quartz as large as 4 cm (1.6 in.) are concentrated in the 

basal part of the member. The pebbles and granules are conspicuous in 

the sand-filled mudcracks at the top of the underlying Chinle Formation. The pebbles, granules and distinctive white chert grains were 

derived from the underlying Chinle Formation and, for the most part, 

represent lag concentrations which were reworked into the basal part of 

the Entrada. The sandstone is characteristically cross-laminated at 

maximum high angles of 20° to 25°. The nature of crossbedding, sorting, and other lithologic and sedimentary features indicate an eolian 

origin for the sandstone. Crossbed orientations indicate a transport 

direction predominantly from the north-northeast toward the southsouthwest throughout the area.

Several features characteristic of the sandstone in the lyanbito are 

also found in the upper sandstone member of the Entrada. Lithology, 

mineralogy, origin, and transport directions are very similar. The upper 

sandstone member at places also contains interbedded siltstone of the 

same type and origin as that in the lyanbito Member. There is, 

however, an overall decrease in grain size and amount of white chert 

grains in the upper member as compared with the lyanbito.

From outcrops north of Continental Divide westward, the upper part 

of the lyanbito Member contains several lenticular sandy siltstone beds 

which range in thickness from 0.3 to 5.5 m (1 to 18 ft). These siltstone 

beds are mineralogically similar to the adjacent sandstone beds; 

however, quartz is slightly more abundant, and the grains are more 

angular in the siltstone. Sand-size grains make up an estimated 10 to 15 

percent of the siltstone beds. Individual beds are horizontally bedded to 

massive and locally contain oscillation ripple marks and mudcracks on 

their upper bedding surface. Polygonal mudcracks on upper bedding 

surfaces of the siltstone beds are commonly as much as 15 to 20 cm 

(about 6 to 8 in.) deep and 2.5 to 3.5 m (about 8 to 12 ft) across. 

Lithologically, the siltstone in the lyanbito Member is indistinguishable from the siltstone of the overlying middle siltstone and 

upper sandstone members of the Entrada.
D8 CONTRIBUTIONS TO STRATIGRAPHY

The origin of the siltstone beds in the lyanbito Member and in the 

overlying members of the Entrada is probably similar to that of desert 

loess. Composition, grain size, and grain shape resemble those of 

modern loess deposits. The general lack of primary internal bedding 

features and the association of the siltstone beds with the eolian 

sandstone also suggest an eolian origin. Stream transport and deposition of most of these finer sediments seems unlikely because 

paleostream channels are only rarely found in association with the 

siltstone. It is more probable that the origin was a combination of loess 

and inland sebkha deposition. Silt winnowed from adjacent dune fields 

by the wind was probably deposited in shallow periodic interdune 

playas or inland sebkhas which were recharged periodically by a fluctuating water table at or near ground level in depressions between 

dunes and adjacent to dune fields in the deeper parts of the depositional 

basins. Ripple marks were probably formed during periods when the 

water table was high and the wind-deposited silts were submerged and 

subject to slight reworking by small wind-generated waves and ripples. 

Mudcracks, in turn, were probably formed during periods when the 

water table was low. Subsequently, the siltstone beds were buried by 

advancing dune sands.

The lyanbito is thickest in the vicinity of Fort Wingate and Gallup, 

where both sandstone and siltstone lithologies are present. The average 

thickness in this area is 40 m (about 130 ft). The maximum thickness of 

44.2 m (145 ft) was measured in the cliffs north of Wingate Station approximately 2 km (about 1.3 m) west of the type locality. The member 

is only about 12 m (about 40 ft) thick in outcrops north of Prewitt (fig. 

1). East of Prewitt the base of the lyanbito Member is covered in most 

places. Thaden and Ostling (1967) and Thaden, Santos, and Raup 

(1967) reported thicknesses of 100 to 120 feet (30.5 to 36.5 m) for the 

member (mapped by them as Wingate Sandstone) in the Bluewater 

and Grants quadrangles.

LOWER AND UPPER CONTACTS

The lower contact is sharp and unconformable throughout the 

Gallup-Grants area and is emphasized by a basal conglomerate, largescale mudcracks, erosional relief, and a sharp contrast in lithology 

between the Chinle Formation and lyanbito Member. The lag concentrations of chert and quartz pebbles in the basal conglomerate are a 

characteristic feature of the unconformity at the base of the Entrada 

Sandstone; for this reason, the lower contact has been informally 

referred to as the "chert-pebble unconformity" in the area of this report 

and elsewhere on the Colorado Plateau. Work by G. N. Pipiringos (oral 

commun., 1969) indicates that the chert-pebble unconformity is 

widespread throughout the Colorado Plateau and adjacent regions. The 

contact is also marked by large-scale mudcracks in the top of the Chinle
IYANBITO MEMBER, ENTRADA SANDSTONE, NEW MEXICO

Formation. These structures are as much as 0.8 m (2.5 ft) wide and are 

filled to a depth as much as 3 m (about 10 ft) with sandstone and 

pebbles from the overlying lyanbito Member. Multicolored claystone, 

siltstone, sandstone, and limestone deposited under humid conditions 

in freshwater fluviatile, lacustrine, and marsh environments of the Chinle 

below the contact contrast sharply with the sandstone and siltstone 

deposited by wind under extremely arid conditions in the desert environments of the Entrada above the contact.

Erosional relief at the lower contact generally is minor because of the 

resistant nature of the underlying limestone of the Owl Rock Member. 

At one place, northeast of lyanbito approximately 2.5 km (about 1.5 

mi), however, the Owl Rock is truncated by the unconformity at the 

base of the lyanbito Member. Laterally from this locality the lyanbito 

Member rests on the Petrified Forest Member of the Chinle for a distance of about 3.2 km (2 mi). No angular unconformity between the 

Chinle Formation and Entrada Sandstone was found.

The upper contact of the lyanbito with the middle siltstone member 

is gradational and difficult to locate in the western part of the area 

because deposition was continuous from the lyanbito Member to the 

middle siltstone member. The contact, for mapping purposes, is placed 

at the base of the lowermost thick siltstone bed which has lateral continuity. From the Continental Divide eastward, the contact is more distinctive in that the lyanbito does not contain siltstone beds in its upper 

part. The contact is placed at the point of lithologic contrast between 

orange eolian crossbedded sandstone of the lyanbito Member and loessdeposited reddish-brown siltstone of the middle siltstone member. The 

contact is also marked by laterally discontinuous beds of light-greenishgray (5GY 8/1) calcareous sandstone 0.3 to 0.6 m (1 to 2 ft) thick at the 

top of the lyanbito Member. These light-colored sandstone beds mark a 

local break in Entrada deposition prior to deposition of the overlying 

siltstone of the middle member in the eastern part of the area. No 

evidence of erosion was found in association with these bleached 

sandstone beds. Primary bedding structures (crossbeds) are preserved 

in these bleached units. These breaks in deposition are intraformational 

because they are laterally discontinuous and the same contact farther 

west is gradational. Similar light-colored sandstone beds can be found 

marking other local breaks in Entrada deposition at other stratigraphic 

levels in the formation. Because of the erratic distribution and nature of 

these minor breaks, they are not considered evidence of a major unconformity when found coincident with the otherwise conformable lyanbito middle siltstone member contact.

AGE AND PREVIOUS CORRELATIONS

Jurassic rocks between the Chinle Formation and Todilto Limestone 

in the Gallup-Grants area have been variously assigned in past studies
TABLE 1. Nomenclature for the stratigraphic interval between the Chinle Formation and 

Dutton

(1885)

Baker, Dane,

and Reeside 

(1947)

Rapaport,

Hadfield, and 

Olson (1952)

Smith

(1954)

Todilto Limestone

Wingate 

Sandstone

(Triassic)

Entrada 

Sandstone 

(Jurassic)

Carmel

Formation 

equivalent 

(Jurassic)

Glen Canyon

Group 

Wingate(?) 

Navajo(?) 

equivalent

(Jurassic)

Entrada 

Formation 

(Jurassic)

Carmel

Formation 

(Jurassic)

Wingate 

Formation 

(Jurassic)

Jurassic)

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Entrada £

Upper 

member

Lower 

member

Wingate(?) 

Formation 

(Jurassic)

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Chinle Formation
IYANBITO MEMBER, ENTRADA SANDSTONE, NEW MEXICO

(table 1). Jurassic rocks in the Gallup-Grants area are isolated from 

equivalent rocks elsewhere on the Colorado Plateau, and abruptly 

changing facies and lack of fossils have made previous correlations difficult and confusing. Because of this fact, correlation of the lyanbito 

Member with equivalent rocks outside of the Gallup-Grants area is purposely avoided in this report. Additional study is necessary before sound 

regional correlations can be made with certainty.

The age of the lyanbito Member is considered to be Late Jurassic in 

this report. The absence of fossils in the lyanbito Member necessitates 

assignment of the unit to the Late Jurassic based on stratal and 

depositional relations with adjacent units. Similarity in origin and 

lithology, as well as the conformable relation with overlying members of 

the Entrada, indicates these units to be similar in age. Deposition was 

continuous from the lyanbito to the middle siltstone member. Previous 

assignment of lyanbito rocks to the Upper Triassic Wingate Sandstone 

(table 1) was based on the presence of an unconformity believed to occur 

between the lyanbito and middle siltstone members. No evidence of 

such an unconformity is present.

Rocks of the lyanbito Member were originally included in the 

Wingate Sandstone as named and described by Button in 1885 (p. 136- 

137). The name Wingate was derived from Fort Wingate, located about 

16 km (about 10 mi) east of Gallup. Excellent exposures of the sequence 

lie in the orange cliffs, locally called the "Wingate cliffs," about 1.9 km 

(about 1.2 mi) north of Wingate Station. Subsequent workers have considered this to be the locality described by Button. Button's locality is 

about 2 km (about 1.3 mi) west of the type lyanbito locality.

Baker, Bane, and Reeside (1947) correlated the Entrada Sandstone 

at the type locality in the San Rafael Swell of central Utah with the upper part of Button's Wingate Sandstone in the Fort Wingate area. At 

the same time they abandoned the type locality but retained the name 

Wingate for the lowermost formation of the Glen Canyon Group. The 

lower part of Button's Wingate (lyanbito and middle siltstone members 

of the present report) was divided, respectively, into equivalents of the 

Glen Canyon Group and Carmel Formation (table 1). Baker, Bane, and 

Reeside were uncertain as to which formation of the Glen Canyon 

Group was present in the Fort Wingate below their Carmel equivalent, 

but they suspected that it was either the Wingate, as redefined, or an 

equivalent of the Navajo Sandstone.

Buring the period 1947-57, Rapaport, Hadfield, and Olson (1952), 

and Smith (1954) made other interpretations in correlation and 

nomenclature of the Entrada interval (table 1).

Harshbarger, Repenning, and Irwin (1957, p. 8, 35) confirmed the correlation with the Entrada made by Baker, Bane, and Reeside (1947) but 

were not in agreement with correlation of the Carmel Formation into 

the Fort Wingate area. Therefore, they recognized two informal
D12 CONTRIBUTIONS TO STRATIGRAPHY

members of the Entrada in the Fort Wingate area, namely the "medial 

silty member" and the overlying "upper sandy member." The Glen Canyon equivalents below the Entrada were correlated with the 

Lukachukai Member of the Wingate as defined in northeast Arizona 

(Harshbarger and others, 1957, p. 10).

REFERENCES CITED

Baker, A. A., Dane, C. H., and Reeside, J. B., Jr., 1947, Revised correlation of Jurassic 

formations of parts of Utah, Arizona, New Mexico, and Colorado: Am. Assoc. 

Petroleum Geologists Bull., v. 31, p. 1664-1668.

Button, C. E., 1885, Mount Taylor and the Zuni Plateau [N. Mex.]: U.S. Geol. Survey 6th 

Ann. Rept., p. 105-202.

Harshbarger, J. W., Repenning, C. A., and Irwin, J. H., 1957, Stratigraphy of the uppermost Triassic and the Jurassic rocks of the Navajo Country: U.S. Geol. Survey Prof. 

Paper 291, 74 p.

Rapaport, tving, Hadfield, J. P., and Olson, R. H., 1952, Jurassic rocks of the Zuni uplift, 

New Mexico: U.S. Atomic Energy Comm. RMO-642, Tech. Inf. Service, Oak Ridge, 

Tenn., 47 p.

Smith, C. T., 1954, Geology of the Thoreau quadrangle, McKinley and Valencia Counties, New Mexico: New Mexico Bur. Mines and Mineral Resources Bull. 31, 36 p.

Thaden, R. E., and Ostling, E. J., 1967, Geologic map of the Bluewater quadrangle, Valencia and McKinley Counties, New Mexico: U.S. Geol. Survey Geol. Quad. Map GQ679.

Thaden, R. E., Santos, E. S., and Raup, O. B., 1967, Geologic map of the Grants 

quadrangle, Valencia County, New Mexico: U.S. Geol. Survey Geol. Quad. Map GQ681.

AU.S. GOVERNMENT PRINTING OFFICE: 1974-677-305/10