Core Logs from Bristol 

Cadiz, and Danby Dry 

Lakes, San Bernardino 

County, California

By A. M. BASSETT, D. H. KUPFER, and F. C. BARSTOW

GEOLOGIC INVESTIGATIONS IN THE MOJAVE DESERT 

AND ADJACENT REGION, CALIFORNIA

GEOLOGICAL SURVEY BULLETIN 1045-D

A detailed description of cores from 

a chain of three dry lake basins

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON j 1959
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

The U. S. Geological Survey Library has cataloged this publication as follows:

Bassett, Alien Mordorf, 1925-

Core logs from Bristol, Cadiz, and Danby Dry Lakes, San 

Bernardino County, California; a detailed description of 

cores from a chain of three dry lake basins. By A. M. 

Bassett, D. H. Kupfer, and F. C. Barstow. Washington, 

U. S. Govt. Print. Off., 1959.

iii, 97-138 p. fold, map, diagr. (in pocket) 25 cm. (U. S. Geological Survey. Bulletin 1045-D. Geologic investigations in the 

Mojave Desert and adjacent region, California)

Bibliography: p. 111.

1. Borings California San Bernardino Co. I. Title, n. Title: 

Bristol, Cadiz, and Danby Dry Lakes, San Bernardino County, California. (Series: U. S. Geological Survey. Bulletin 1045-D. Series: 

U. S. Geological Survey. Geologic investigations in the Mojave 

Desert and adjacent region, California)

557.9495

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

Washington 25, D.C.
CONTENTS

.Abstract____.-._.-.._____-__.____________________ 97

Introduction. __ ______ ___________________________________________.. 97

Acknowledgments___________._----_____-___-_.___________ __. 991

Geologic setting________________________________________________ 100

Logging methods______________-_-_-_----__-_-_____._________ 102

Summary of the core logs________________________________________ 104

Bristol 2____.___________________________________ 104

Cadiz 1____________________________________ 105

Danby 1.____________.__-_._.__________________ 107

Danby 2_____________._-_____-_______-.______.___ 109

Correlations between cores__.-___-_-_-_-_____-__________________ 110

Literature cited____-_______._-_---__-__-_--_--_--_________-_-___ Ill

Core logs_____..___________._______________ 112

ILLUSTRATIONS

PLATE 4. Graphic logs of cores from Bristol, Cadiz, and Danby Dry

Lakes___.___._-___-__-_-___-___-______________ In pocket

FIGURE 5. Index map showing the location of Bristol, Cadiz, and Danby

Dry Lakes and of the holes drilled____________________ 98

m

GEOLOGIC INVESTIGATIONS IN THE MOJAVE DESERT AND ADJACENT

REGION, CALIFORNIA

CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY 

LAKES, SAN BERNARDINO COUNTY, CALIFORNIA

By A. M. BASSETT, D. H. KUPFER, and F. C. BARSTOW

ABSTRACT

Detailed core logs of four holes drilled in Bristol, Cadiz, and Danby Dry Lakes 

in southeastern San Bernardirio County, Calif., are given in the present report. 

These 3 dry lakes lie in a chain of basins having a drainage area of 4,000 square 

miles which is made up of alluvial slopes and of mountains composed of granitic, 

metamorphic, and volcanic rocks. Rainfall in the basins averages less than 3 

inches annually.

In Bristol Dry Lake, 1 hole was drilled to a depth of 1,007 feet, and penetrated 

layers of dense clay alternating with salt. About 40 percent of the recovered 

core is halite, ranging from scattered crystals in clay to massive beds more than 

8 feet thick. In Cadiz Dry Lake, 1 hole was drilled to a depth of 500 feet. The 

core is composed of clay, silt, and sand, with scattered gypsum crystals in small 

quantities, and a single salt layer, 1 foot thick, lying about 9 feet below the surface. 

Bedding in this core is horizontal down to a fracture at a depth of about 256 

feet; from there to the bottom, the dip increases gradually to a maximum of 35°. 

In Danby Dry Lake, 2 holes were drilled: the first and more northerly one to a 

depth of 880 feet and the southerly one to a depth of 460 feet. 'Both cores are 

composed of clastic sediments ranging from clay to coarse sand with fine sand 

the most abundant. Crystalline gypsum in silt occurs between 310 and 520 feet 

in the northern hole and between 278 arid 334 feet in the southern hole. The 

northern hole was drilled in gravel for the last 20 feet. No salt beds were cut in 

either of the Danby holes despite the occurrence of commercial salt deposits 

elsewhere on the surface of the playa. Correlation of sediments between any of 

these cores, even between those from the same basin, is difficult and seldom 

convincing. .

Fossils were found in the Cadiz core and in both Danby cores. The most 

abundant fossils are Chara, the calcified seeds of the Charophyta algae. Foraminifers, ostracodes, gastropods, pelecypods, and barnacles, in order of decreasing abundance, occur at rare intervals in these three cores.

INTRODUCTION

As part of a program to study the saline deposits of the Mojave 

Desert region, the U. S. Geological Survey had four holes drilled on 

contract in the Bristol, Cadiz, and Danby Dry Lake basins in southeastern San Bernardino County, Calif, (fig. 5). This drilling was 

carried out between January 5 and March 16, 1953, and cores were 

taken the full length of all holes. The logs of these cores are here

97
98 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

FIOUEE 5. Index map showing the location of Bristol, Cadiz, and Danby Dry Lakes and of the holes 

drilled. Also shown are the elevations (in feet) of dry-lake surfaces and of the passes that would have 

become spillways had the basins ever been filled by lakes.

presented written in summary and in detail as well as in graphic 

form (pi. 4). 

A summary of the drill-hole data is given in the table below.

Drill holes in Bristol, Cadiz, and Danby Dry Lakes 

[Gore size was 2% inches throughout, and the core barrel was 10 feet long] .

Drillhole

Bristol 1 > ____

Bristol 2 _____

Cadiz !_______ .

Danby 1 _.

Danbv 2 _____

Depth 

(feet)

1,006

1,007

500

880

460

Core 

recovery 

(percent)

52

47

52

61

Location 

(San Bernardino base line and meridian)

C., sec. 34, T. 5 N., R. 12 E.

SW & sec. 3, T. 4 N., R. 12 E.

NE ft, sec. 4, T. 2 N., R. 15 E.

NE %, sec. 19, T. 2 N., R. 18 E.

SE K. sec. 34. T. 2 N.. R. 18 E.

i Bristol core hole 1 was drilled In 1952 cooperatively by the National Chloride Co. and the California 

Salt Co., both operating on Bristol Dry Lake. The recovered core was subsequently logged by Kupfer. 

A graphic log is given on plate 4, but the core is not treated further In this report.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 99

These 3 playas lie between long 115° and 116° W. and between 

lat 34° and 35° N. The main line of the Santa Fe railway and Highway 66 between Barstow and Needles, Calif., cross the area north of 

the playas. The Parker Branch of the Santa Fe and a parallel dirt 

road cut southeastward from the railroad town of Cadiz along the 

eastern border of the basins containing the playas. The very small 

population of the region, mainly in the town of Amboy, is supported 

by the salt and brine industry of Bristol Dry Lake and by supplying 

service for the highway and railroad.

Previous geologic work consists of regional reconnaissance studies 

by N. H. Barton (1915), B. G. Thompson (1929, p. 660-711), J. C. 

Hazzard (1933), and the California Bepartment of Public Works, 

Bivision of Water Resources (1954). A geologic reconnaissance 

covering the region surrounding these dry lakes was made during the 

fall of 1953 by the first two authors of this report; it is now hi preparation for publication. Results of the search for potash during World 

War I, including chemical analyses of brines from Bristol and Cadiz 

Bry Lakes, were published by H. S. Gale and W. B. Hicks (1920, 

p. 418-419). Comments on the composition, production, and reserves 

of salines in these dry lakes have been published by F. L. Hess (1910, 

p. 25-27), W. C. Phalen (1919, p. 185), B. F. Hewett and others 

(1936, p. 94-95), W. E. Ver Planck (1952, p. 47-48; 1954, p. 7-8), 

and L. A. Wright and others (1953, p. 217-242). A detailed description of Bristol Bry Lake was published by H. S. Gale (1951). No 

detailed published reports on Cadiz or Banby Bry Lakes are known 

to the writers.

ACKNOWLEDGMENTS

Mineral identifications were made with immersion oils by Robert B. 

Alien, then of the U. S. Geological Survey. The writers appreciate 

the cooperation given by personnel of the operating salt companies 

on Bristol Bry Lake, especially by Mr. M. M. Stephans, of the National Chloride Co. of America.

The fossils from Banby drill hole 1 were studied and identified by 

W. P. Woodring, Ruth Todd, and I. G. Sohn, of the U. S. Geological 

Survey, and by Manly Natland, of the Richfield Oil Corp. Those 

from Banby drill hole 2 were identified by W. P. Woodring and 

P. B. Smith, of the U. S. Geological Survey, and those from Cadiz 

drill hole 1 were identified by P. B. Smith. K. E. Lohman, of the 

U. S. Geological Survey, studied the samples from Banby 1 for diatoms but found none. Present information on the fossils is inadequate to determine their a,ge; further work is planned.
100

GEOLOGIC SETTING

Bristol, Cadiz, and Danby Dry Lakes occur in a trough that trends 

west-northwest and is divided into three separate basins by northwesttrending mountain ranges that project into the trough. The dry 

lakes occupy the lowest parts of these basins and ultimately receive 

all the unevaporated water from the surrounding mountain slopes, a 

total drainage area of about 4,000 square miles. The rainfall of this 

region, however, is extremely low (2.28 in. annual average in the 

basins x ), and the rate of evaporation extremely high; water, therefore, 

never stands on the playas except for a short period after heavy rain 

storms.

The mountain ranges surrounding these basins are composed principally of plutonic and metamorphic rocks of pre-Tertiary age. Limestone is fairly abundant in the mountains northeast of Bristol and 

Cadiz basins and absent elsewhere. Tertiary lavas and pyroclastic 

sediments are the predominant rocks west and northwest of Bristol 

Dry Lake. Volcanic rocks are less common east and northeast of the 

basins and absent south of them. No saline-bearing sediments crop 

out within the area tributary to the playas.

Two Quaternary basalt flows lie within the drainage basin of Bristol 

Dry Lake, a small one on the south slope of Lead Mountain and a 

larger one bordering Bristol playa on the west. The larger flow, 

which issued from Amboy Crater (also called the Bagdad Cinder 

Cone) 3 miles southwest of Amboy, poured out over a large playa 

dividing it into two unequal parts. The eastern part is Bristol Dry 

Lake and the western part is called Alkali Dry Lake. Although only 

briefly examined, Alkali Dry Lake appears to be similar to Bristol Dry 

Lake in virtually all respects. The large dry lake, which was formed 

before the deposition of the lava, was nearly 100 square miles, about 

twice the size of the present Bristol Dry Lake.

Bristol and Cadiz playas are separated by a low alluvial divide extending beyond the northeastern termination of the Coxcomb Mountains (fig. 5). This divide rises only 52 feet above the lowest part of 

Bristol Dry Lake and 104 feet above the lowest part of Cadiz Dry Lake. 

But for this low alluvial divide, Cadiz Valley would be a part of Bristol 

basin. Thompson (1929, p. 696) proposed the name Amboy Lake for a 

Pleistocene body of water which he thought existed in the large basin 

containing both Bristol and Cadiz playas. If this large basin had contained an overflowing lake in late Pleistocene time, such a lake would 

have attained a depth of more than 450 feet and a surface area of about 

500 square miles before its waters could have escaped through the 

lowest pass in the Iron Mountains and flowed into Danby playa.

' Compiled by D. O. Thompson (1929, p. 90-91) from U. S, Weather Bureau records maintained for a 

period of 17 years at Bagdad, Calif.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 101

Danby Dry Lake is the sump of a separate drainage basin, known as 

Ward Valley, that extends about 50 miles north of the playa, and has a 

drainage of about 1,000 square miles. A lake in this basin, for which 

Thompson (1929, p. 708) suggested the name Ward Lake, would have 

overflowed through a divide to the southeast, near Rice, and into the 

Colorado River.

In .none of the three basins, however, have the writers found shoreline features, wave-cut terraces, or gravel bars, such as occur commonly 

around other desert basins that did contain overflowing Pleistocene 

lakes, though their absence does not constitute proof that such lakes 

never existed. This evidence is in accord with the theoretical argument that such huge bodies of water would not be expected even 

during pluvial periods, because the entire drainage basin lies within 

one of the most arid regions of the country. It seems likely that these 

basins contained only very shallow perhaps ephemeral lakes that 

did not overflow during the late Pleistocene epoch.

All three playas have more than one type of surface. The principal 

type is a puffy efflorescent surface, called "self-rising ground" caused 

by the evaporation of capillary brine. It is generally believed to indicate a basin with no external underground drainage. Somewhat less 

common in these playas is the clay flat a surface of smooth, hard, 

compact clay which indicates the water table lies at considerable 

depth. A third type is the salt crystal surface, in which salt crops 

out at the surface of the playa or is covered only by a relatively thin 

veneer of silt or clay.

Bristol Dry Lake is mostly efflorescent ground but has a brinesoaked crystal body very near the surface in its lowest part near the 

southwestern border of the playa. This occurrence of efflorescent 

ground and near-surface brine suggests that there is no underground 

escape of water from Bristol Dry Lake to the lower ground of Cadiz 

Valley. This, in turn, suggests that the pass between the two basins 

consists of a bedrock barrier that lies at relatively shallow depth 

beneath alluvium. Cadiz Dry Lake has, near the center of the playa, 

a similar brine and salt body surrounded by large areas of puffy 

ground, and in the northern part of the playa has many expanses of 

dry, clay flats. Danby Dry Lake has salt crystal bodies at the surface at both the north and south ends of the playa, areas of claypan 

along the southeastern part, and efflorescent ground for most of the 

rest of the playa.

Gypsum-capped pedestals on Cadiz and Danby Dry Lakes are 

remnants of a once higher playa surface that has been almost completely removed, probably by a combination of deflation and water 

erosion. This erosion is probably initiated by deflation and aided 

later by water which tends to level the playa surface after the wind

48865S 69 2
102 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

has created irregularity in it. Elsewhere the surface of Danby DryLake is cut by numerous drainage channels, more than 5 feet deep 

and as much as 100 feet wide, which drain toward a sump near the 

southwest edge of the playa.

LOGGING METHODS

All cores were logged in the field within a few hours after removal 

from the holes and while still wet. They have not been relogged in 

the laboratory. The core from Bristol drill hole 2 was logged to a 

depth of 657 feet by Kupfer, and from there to the end (1,007 feet) 

by Bassett, who also relogged in greater detail the first 30 feet. The 

core from Cadiz drill hole 1 was logged by Bassett; all the core from 

Danby drill holes 1 and 2 was logged by Barstow.

In compiling the final logs, the following conventions were established for uniformity.

Recovery. When the core recovered from any given run2 was less 

than 100 percent, there was generally no reliable indication of the 

position of the recovered core within the run. For all of the logs 

here discussed, the core recovered has been arbitrarily assigned to 

the lower part of the run and the missing portion to the upper part. 

The average recovery for these 4 holes was 53 percent.

Location is given to the nearest tenth of a foot, but this does not 

imply accuracy of that degree in depth below the surface. It is 

intended to place a specific location in the core below the nearest 

accurately known depth.

Caving. Between drilling runs, especially when the drill was idle 

overnight, material often caved in from the walls higher in the hole, 

and was unavoidably recovered in the core barrel along with the true 

core. In general, where this material was soft disordered mud without form, it was neither saved nor logged. However, where material 

at the top of the run, without form, and generally soft and disordered, 

might represent sediment in place, it was kept and logged and indicated in the logs as "probably slumped material." Some other portions of the core that appeared to have normal form, and were not 

of anomalous lithologic character, may also have been slumped material, but were not recognized as such, nor so logged.

Sediment names, textures, and structures. Sediment names are in 

accord with those suggested by Wentworth (1922). The term "massive" as used throughout the logs for Bristol core 2 and Cadiz core 1

1 The term "run" refers to the length of hole drilled between removals of the core barrel from the hole. 

Usually a run was 10 feet.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 103

is intended to mean that stratification is difficult or impossible to 

see with the unaided eye. When used as a modifier of salt, "massive" 

means that the salt occurs in compact crystalline masses, rather than 

as isolated crystals embedded in a matrix. The term "clay" is used 

in the present report only in the sense of particle size. The mineralogy of the fine-grained aggregate was not established.

The dip of the bedding in all cores is within a few degrees of horizontal except below 256 feet in Cadiz core 1.

Nearly all core in the four holes is calcareous; that is, it effervesces 

in cold dilute hydrochloric acid. Because of this uniformity, the 

word "calcareous" has not been added to the logs of the Bristol and 

Cadiz cores; but it has been retained from the original field logs for 

the Danby cores. The presence of sodium chloride in small quantities 

in the cores could not be discerned because the drilling fluid used for 

all holes was the brine of Bristol Dry Lake. The presence of calcium 

chloride, which rarely forms in the solid state, also could not be determined because of the high concentration of calcium chloride in 

the Bristol Lake brine drilling fluid.

Colors. In most lithologic descriptions colors have been named 

and numbered according to the "Rock-Color Chart" distributed by 

the Geological Society of America (Goddard and others, 1951). 

Where names included in the "Rock-Color Chart" are used without 

the number symbol, these colors were identified by memory without 

direct comparison with the chart. In places where names unlike 

those on the chart are used, it means no comparison with the chart 

was made, nor had the chart been utilized recently enough to permit 

color identification by memory. This latter category applied mostly 

to the Bristol core in which the color chart was used only rarely.

All core was logged wet, thus it had darker color values than when 

dry. For this reason the addition of color readings after the cores 

had dried could not be made without relogging all cores for color 

uniformity.

Salt. In Bristol core 2, salt ranges from pure massive beds to 

isolated crystals disseminated in clay. The following approximate 

percentage ranges are intended for the core descriptions as used in 

the detailed log:

Salt 

(percent)

Salt, massive________________________________________ 100

Salt, crystalline or massive; with some clay; orl 7K_QQ 

Salt crystals in clay. J---- ----

Salt, crystalline, and brown clay______._________ 50-75

Clay, brown, and crystalline'salt._________________ 25-50

Clay, brown; contains some salt_________________________ 1-25
104 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

SUMMARY OF THE CORE LOGS

BRISTOL 2

The core of Bristol 2 is composed almost exclusively of salt and 

clay. About 40 percent of the total recovered core is composed of 

salt, which occurs in massive beds up to 12 feet thick (recovered 

core) and as scattered crystals in clay, ranging from the major constitutent to rare isolated crystals. Pure or nearly pure salt beds 

(more than 90 percent salt) at least 1 foot thick, number more than 

40 and have an aggregate thickness of 142 feet. Seven of these are 

greater than 5 feet thick. Such nearly pure salt layers occur regularly 

throughout the entire core except between the principal commercial 

bed, at a depth of about 8 feet, and the next nearly pure salt layer at 

153 feet. Brine, rich in calcium chloride, is pumped from the upper 

salt bed. Disintegration and persisting dampness of the core in 

certain places suggest the presence of calcium chloride brine at deeper 

levels. However, the use of Bristol lake brine as drilling fluid makes 

this difficult to confirm.

The most abundant sediment is a dark yellowish-brown or graygreen clay, frequently silty or sandy, generally dense and massive, 

and in part compact and weakly fissile. The color of the clay is in 

part related to salt content, for clay next to massive salt is always 

green. The contacts between green and brown clay are irregular as 

if related to secondary alteration, not sharp as if a primary depositional 

feature. Much of the clay, especially hi the upper part of the core, 

contains disseminated sand grains. The clay is calcareous throughout 

and contains small limy nodules and patches and numerous small 

flecks and pods of anhydrite. Silt and very fine sand layers are 

common in the upper 30 feet of core, laminated silt continues to 

about 130 feet, and below that both are uncommon.

A 1-inch bed of white volcanic tuff composed of glass shards occurs 

at a depth of about 667 feet, and a 1-inch argillaceous lunestone layer 

was noted at a depth of about 720 feet. In the few places where 

bedding could be observed, the attitude was virtually horizontal. No 

fossils were found.

Summary log of Bristol 2

Depth

(feet) Description

8 Clay, silt, and very fine sand, olive-gray and yellowish-brown; with a salt

	crust and a few scattered salt crystals and limy nodules. 

12 Salt, massive, commercial bed; with olive-gray silt and clay. 

90 Clay, gray-green; with salt crystals and sand grains. 

110 Clay, green, and brown silt, laminated; some salt crystals. 

138 Clay and silt, reddish-brown; with salt crystals. 

153 Clay, gray and green; with salt crystals. 

172 Salt, massive; 3 beds of 2.5 ft average thickness.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 105

Summary log of Bristol 2 Continued

Depth . . (feet) Description

255 Clay and salt, interbedded; clay is grayish green; several salt beds over

	1.5 ft thick.

270 Salt, massive; beds 3.4 and 5.3 ft thick.

285 Clay, sandy, brown, laminated; some salt crystals,

305 Salt, massive; 4 beds recovered.

320 Clay, dark-brown; some salt crystals.

336 Salt, massive, and dark-brown clay; 3 salt beds, thickest one 5.7 ft thick,

421 Clay, brown, laminated; interbedded with massive salt layers.

430 Salt, massive, interbedded with brown clay.

508 Clay, brown, interbedded with salt layers 2 to 12 in. thick.

516 Salt, massive, pure; single bed 7.5 ft thick.

564 Clay, brown, and massive salt.

574 Salt, massive; 3 beds each about 1 ft thick.

659 Salt and brown clay, interbedded.

665 Salt, massive; with some brown clay and grayish-olive silt.

686 Clay and salt; with 1 in. volcanic tuff bed at 667 ft.

719 Salt, massive, and some green and brown clay; thickest salt bed is 8.4 ft

	thick.

726 Clay, brown; with limestone layer 2 in. thick at 720 ft.

735 Salt, massive; with some green clay.

822 Clay and salt, interbedded; in about equal amounts.

834 Clay, brown and green, massive; with limy nodules throughout.

852 Salt, massive, crystalline; with green and brown clay seams.

864 Clay, brown and green; with some salt crystals and seams.

980 Salt and brown clay, interbedded; salt beds up to 5 ft thick.

1,007 Clay, brown and green, massive; with salt crystals and flecks of anhydrite.

CADIZ 1

Clay, silt, and sand constitute nearly the entire sedimentary 

sequence exposed in Cadiz core 1. The predominant sediment is 

a dense clay of dark yellowish brown (1017? 3/2) frequently mottled 

or splotched with dusky olive green (5GY 4/2). In several places, 

quartz grains of coarse and very coarse sand size occur disseminated 

in the dense clay. Clastic sediments coarser than clay range in grain 

size from silt to medium sand, are generally yellowish brown, and 

are composed, principally of quartz but also of the other common 

minerals of granitic rocks. To a depth of 240 feet, about half .of the 

core is composed of sand layers. Below 240 feet, silt makes up about 

a third of the core and sand is rare.

Massive crystalline salt, 9 feet below the surface, forms a layer 

about 1 foot thick. It contains a sodium chloride and calcium chloride 

brine at the present water level. Salt also occurs as thin porous 

crystalline layers interbedded with clay and silt in the top few feet 

of the core. No other salt beds were encountered.

Gypsum in small quantities is fairly common from a depth of about 

25 to 158 feet and sparse from there to 400 feet, below which none
106 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

was observed. It occurs scattered through the sand and clay as 

"fishtail" twins, wedge-shaped crystals, fibrous veinlets, crystalline 

powder, and thin stringers. The entire core is calcareous.

A very dense orange-brown or moderate-brown (SYR 4/4) clay, 

contrasting conspicuously with the normally yellowish-brown clay, 

contains fairly abundant white, tan; and grayish green irregular limy 

patches and very hard limestone nodules. This clay is present in a 

13-foot bed between 158 and 171 feet and again intermixed with 

bluish-gray, reddish-brown, and other variously colored clays between 

355 and 370 feet.

Fossils occurring in limestone nodules and adjacent clay beds 

were recovered throughout much of the core below 267 feet. They 

were identified by P. B. Smith, of the U. S. Geological Survey, who 

reported the faunal assemblage as similar to that found earlier in the 

cores from Danby Dry Lake and to consist of "Several species of 

rotaliiform Foraminifera (shallow water), ostracodes, and a great 

abundance of Chara (algae seeds, not useful in determining age). 

These fossils all indicate shallow brackish water" (written communication, 1953). Several chitinous spicules also were found. The 

 evidence is insufficient to determine with certainty whether this 

represents a marine or nonmarine environment of deposition.

A slickensided fracture dipping 57°, at a depth of about 256 feet, 

marks a change in the dip of the bedding. Above that point, all 

bedding is horizontal; below it, the dip of the beds increases gradually 

from 10° to a maximum of 35° at 470 feet, the lowest bedding plane 

seen. These angles are probably too large to be explained by deviation of the drill hole from vertical, especially in view of the softness 

of the material. The dip of the beds may be attributed to folding 

or tilting of the lower beds, suggesting a different age for them than 

for the flat-lying beds unconformably(?) above them. However, 

these beds are similar lithologically and in color both above and below 

the fracture. The dip might be explained by post-depositional 

compaction of the clays. This compaction may have been greater 

at the center of the playa where the clays were thickest, with the 

result that the beds near the edge of the playa dip toward the center. 

The fossils are restricted to the tilted beds.

Summary log of Cadiz 1

Depth (feet) Description

8 Sand, medium and fine, salty, over grayish-olive clay interlayered with

porous salt and gypsum sand. 

10 Salt, massive, crystalline; 1 ft recovered. 

158 Clay and fine sand, yellowish-brown and grayish-green; with gypsum

crystals disseminated throughout. 

171 Clay, orange-brown, very dense; with tan limestone nodules.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 107

Summary log of Cadiz 1 Continued

Depth

(feet) Description

208 No core; probably unconsolidated sand.

239 Sand, fine to very fine, rusty and moderate orange-brown; with thin seams

of clay.

268 Clay, gray, gray-brown, and brown; with silt interlayers. 

(256) Fracture; horizontal beds above; inclined beds below. 

270 Limestone, greenish-gray, very hard, fossiliferous (Chara), interbedded

with brown clay and silt. 

300 Clay and silt, brown, interbedded; with fossiliferous (Chard) limy nodules

and patches. 

333 Clay, green and brown; with minor amounts of gypsum; coarse sand grains

throughout.

335 Limestone and clay, grayish-green, abundantly fossiliferous. 

427 Silt and clay, brown, sparsely fossiliferous throughout; with limestone

nodules in mottled green and brown clay below 368 ft. 

434 Clay and silt, orange-brown and reddish-brown. 

500 Clay, sandy clay, and silt, brown and orange-brown; with grayish-green

fossiliferous limestone nodules.

DANBY 1

Danby 1 is the more northerly and deeper (880 ft) of the 2 holes 

drilled in Danby Dry Lake. Sand, ranging in grain size from very 

fine to medium, constitutes about half of the sediment of this core. 

Clayey silt and silty clay, interbedded and intergradational, are next 

most abundant. Massive and laminated clays make up less than 

10 percent of the core, and gravel was the only material recovered 

from the bottom 20 feet of the hole. Crystalline gypsum is very 

abundant in 2 layers, the larger one over 200 feet thick. Limestone 

is a minor constituent. Despite the presence of commercial deposits 

of salt at the surface at both the northern and southern ends of the 

playa, no evidence of salt beds was found in this core.

The color of the upper 130 feet of the core is yellowish brown, but 

throughout the remainder, olive gray, dark and light greenish gray, 

pale bluish gray, and dark and light gray are the predominant colors. 

All of the core is calcareous, and, in the upper part, much of it is 

salty.

Crystalline gypsum, both massive and as interspersed crystals in 

mixed fine sediments, occurs in a 6-foot bed about 10 feet below the 

surface and in a 210-foot bed between 310 and 520 feet depth. In 

both of these layers, gypsum constitutes nearly half of the material 

present. Bassanite, a hemihydrate of calcium sulfate, identified by 

R. D. Alien and Henry Kramer (1953), occurs at depths of about 

365 and 510 feet.

Light-gray and light-brown brecciated opaline shale occurs in a 

X-inch layer of pale greenish-gray argillaceous limestone at a depth 

of about 570 feet. Some parts of the opaline material are pure silica
108 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

and cannot be scratched with a steel knife, but other parts with 

identical appearance are evidently incompletely opalized as they 

can be scratched. The largest of the breccia pieces is 1 inch long, 

but most are small sharply angular fragments one-tenth of an inch 

thick.

Dark grayish-green lamellar clay between about 570 and 590 feet, 

is composed of layers one-tenth of an inch thick separated by paperthin laminae of white strongly calcareous clay. Between 780 and 

790 feet, several beds of light-gray limestone, 1 or 2 inches thick, 

occur in a medium-gray to nearly black massive limy clay. Directly 

beneath these limestone beds is a 17-foot section of thinly laminated 

fissile shale with laminae alternating between very pale yellowish 

gray and dark bluish gray.

Isolated pebbles in clay and silt were struck at depths of 801, 840, 

and between 845 and 850 feet. From 860 feet to the bottom of the 

hole at 880 feet, only coarse gravel, pebbles, and cobbles were recovered.

Fossils were located at depths of 732.4, 738.4, 785.9, and 845.0 

feet. These samples were studied by W. P. Woodring, Ruth Todd, 

and I. G. Sohn, of the U. S. Geological Survey, and Manly Natland, 

of the Richfield Oil Corp. They reported (written communications, 

1953) a fauna consisting of foraminifers, ostracodes, pelecypods, 

gastropods, and a barnacle. Chara seeds are also present. K. E. 

Lohman, of the U. S. Geological Survey, searched the samples for 

diatoms but found none.

Summary log of Danby 1 

Depth 

(feet) Description

10 Silt, clayey, dark yellowish-brown, salty.

16 Gypsum, crystalline, and dark yellowish-brown clayey silt.

50 Silt, clayey, yellowish-brown, salty, massive.

130 Silt, clayey, interbedded with fine and medium sand and silty clay, mostly 

yellowish-brown.

310 Sand, fine, interbedded with clayey silt and silty clay, mostly olive gray.

520 Gypsum, crystalline, occurring in and interbedded with dark yellowishbrown and olive-gray clay, silt, and fine sand.

533 Sand, fine, silty, interbedded with clayey silt; multicolored but predominantly olive gray and yellowish brown.

570 Clay and some sand, mostly yellowish-gray and light greenish-gray.

590 Clay, lamellar, hard and compact, mostly.-dark greenish-gray.

670 Sand, fine and very fine, silty, olive-gray and dark greenish-gray, poorly 

consolidated; with some clay and limestone.

760 Sand, fine, silty, interbedded with massive and lamellar clay, olive-gray 

and light-gray. Fossils at 732.4 and 738.4 ft.

780 Clay and clayey silt, massive and lamellar, pale bluish-gray and greenishgray; in part with very thin lamellae of white carbonate.

788 Limestone, massive, light-gray, interbedded with massive and lamellar clay. 

Fossils at 785.9 ft.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 109

Summary log of Danby 1 Continued

Depth

(feet) Description . .

805 Clay, fissile, very limy, grayish olive-green to dark-gray alternating with

light-gray; lesser amounts of silt and coarse sand. 

860 Sand, medium and fine, moderate .orange-brown; with some darker brown

silt and clay, and cobbles at 840 and 850 ft. Fossils at 845 ft. 

880 Gravel, primarily angular granodiorite pebbles and cobbles.

DANBY 2

The core from Danby 2 is composed principally of mixed fine-grained 

clastic sediments clay, clayey silt, silty clay, clayey sand, and sand 

ranging from very fine to coarse. Most abundant is very fine sand 

which, in one place, between 180 and 250 feet in depth, is 70 feet 

thick without significant change in grain size or color.

A layer of well-indurated strongly calcareous medium-grained sandstone, between 120 and 130 feet in depth, is distinctive by comparison 

with the usual poorly indurated material. Between about 407 and 

420 feet lies a dense orange-brown clay with tan limy nodules identical 

in appearance with a layer in Cadiz core 1 between 158 and 171 feet. 

Crystalline gypsum embedded in clayey silt extends from a depth of 

278 to 334 feet a thickness of 56 feet. Pebbles were struck at depths 

of 333, 351, and 391 feet, but playa sediments continued below them 

to the bottom of the hole. No salt was cut by this hole, even though 

salt forms a crust on the playa several feet thick less than a mile 

south of the drill site.

Fossils were found at only one point in the core, at a depth of 449 

feet, where they are abundant and comprise a major part of a bed of 

light-buff sand. The fossils identified by W. P. Woodring and P. B. 

Smith are gastropods, pelecypods, foraminifers, Chara, and one 

barnacle.

Summary log of Danby 2

Depth

(feet) Description

38 Clay, silty, light-brown to moderate yellowish-brown,salty.

120 Clay, clayey silt, and clayey very fine sand, yellowish-gray to light-buff.

140 Sandstone, medium-grained, and massive light olive-gray very fine sand.

180 Silt, clayey, light olive-gray, massive.

250 Sand, very fine, light olive-gray, massive.

278 Clay, silty, and clayey silt, light olive-gray, bedded.

334 Gypsum, crystalline, interbedded with moderate yellowish-brown clayey 

silt; gypsum about 40 percent; pebbles at 333 ft.

391 Sand, very fine to coarse, interbedded with silty clay, dark to light yellowish-brown and greenish-gray to light olive-gray; pebbles at 351 and 391 ft.

407 Clay, compact, light olive-gray to greenish-gray.

420 Clay, dense, orange-brown; with pale-buff limy nodules.

460 Sand, fine and very fine, interbedded and intergradational with clayey silt 

and silty clay, variegated colors mostly light gray and buff. Fossils at 

449 ft. 

488653 59 3
110 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

CORRELATIONS BETWEEN CORES

Correlation of sediments is difficult to make within a single-basin 

as well as between separate basins. This points out the need for many 

drill holes in order to test adequately the content of sediments beneath 

a playa. For example, commercial salt deposits occur at both the 

north and south ends of Danby Dry Lake, but the two Danby drill 

holes, which were drilled in-between, penetrated no salt.

Bristol and Cadiz basins are separated only by an almost imperceptible alluvial divide that rises about 50 feet above the lowest part 

of Bristol Dry Lake. It would seem reasonable that the two, being 

parts of the same drainage basin, should have had approximately the 

same sedimentary history. Yet the cores from Bristol and Cadiz 

Dry Lakes have virtually no similarities: the Bristol core consists of 

clay and 40 percent salt; the Cadiz core predominantly of sand and 

silt with only a single bed of salt 1 foot thick. However, it is possible 

that this difference may be only apparent and not real. If nonsalme 

shore facies and salt-bearing central facies both persist in depth, it 

may be that the Cadiz hole was placed too far from the center of the 

playa (inaccessible to the drill rig) and tested only the shore facies, 

whereas the Bristol hole was placed in the lowest part of the playa 

and tested the central facies.

A potential correlation between Cadiz and Danby cores is found 

only in the dense orange-brown clay, which occurs in both cores and 

is a very distinctive unit. It could be the result of the weathering of 

a particular type of rock hi the Iron Mountains, the range lying between 

the two basins, or of some volcanic phenomenon.

Correlation between the two cores from Danby Dry Lake can be 

made only in a general way. The upper 120 to 130 feet of sediment in 

both cores' is a yellowish-brown silty clay, and beneath that in both 

cores the clay is usually plive gray and contains coarse sand grains. 

Both cores have a thick sequence of crystalline gypsum in clay, but 

of widely differing thickness and at surprisingly different depths if 

their time of formation is taken to be similar. Below the gypsum 

layers any correlation between the two Danby holes becomes very 

uncertain.

In Bristol Dry Lake the 2 salt companies operating there cooperatively drilled a hole (Bristol 1) to 1,006 feet. This hole is slightly 

over 1 mile north-northeast of Bristol 2. The log of this core is 

shown graphically on plate 4. It is based on very poor core recovery 

in the lower half (only 37 ft of core between 512 ft and bottom of hole) 

but is adequate to make clear that the numerous salt layers beneath
CORE LOGS PROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. HI

the playa cannot be individually correlated below the top commercial 

bed. Nineteen shallow holes drilled by the Metropolitan Water 

District of Southern California (Gale, 1951) also indicate that the 

salt is widespread, but that the individual beds are lenticular and 

discontinuous.

If the sediments had been deposited hi perennial lakes, a continuity 

of layers within each basin would be expected, and correlation between cores from the same basin would be relatively direct. That 

such correlation is so difficult suggests that the deposits were irregularly laid down in ephemeral lakes as a result of intermittent floodings, 

or that the salines have been redistributed by ground water after 

deposition. In fact, both of these processes were probably effective.

LITERATURE CITED

Alien, R. D., and Kramer, Henry, 1953, Occurrence of bassanite in two desert

basins in southeastern California: Am. Mineralogist, v. 38, p. 1266-1268. 

California Department of Public Works, Division of Water Resources, 1954,

Ground-water occurrence and quality, Colorado River Basin region: Water

Quality Inv. Rept. 14, 59 p., geol. reconn. map. 

Barton, N. H., 1915, Guidebook of Western United States: part C, The Santa Fe

Route: U. S. Geol. Survey Bull. 613, p. 152-155. 

Gale, H. S., 1951, Geology of the saline deposits, Bristol Dry Lake, San Bernardino County, California: California Div. Mines Special Rept. 13, 22 p. 

Gale, H. S., and Hicks, W. B., 1920, Potash: Mineral Resources U. S., 1917, pt. 2:

U. S. Geol. Survey, p. 397-481. 

Goddard, E. N., chm, and others, 1948, Rock-Color chart: Washington, Natl.

Research Council (republished by Geol. Soc. America, 1951). 

Hazzard, J. C., 1933, Notes on the Cambrian rocks of the eastern Mohave Desert,

California: California Univ., Dept. Geol. Sci. Bull., v. 23, p. 57-70. 

Hess, F. L., 1910, A reconnaissance of the gypsum deposits of California: U. S.

Geol. Survey Bull. 413, 37 p. 

Hewett, D. F., and others, 1936, Mineral resources of the region around Boulder

Dam: U. S. Geol. Survey Bull. 871, 197 p. 

Phalen, W. C., 1919, Salt resources of the United States: U. S. Geol. Survey Bull.

669, 284 p. 

Thompson, D. G., 1929, The Mojave Desert region, California: U. S. Geol.

Survey Water-Supply Paper 578, 759 p. - : Ver Planck, W. E., 1952, Gypsum in California: California Div. Mines Bull.

163, 151 p. 

 ^- 1954, Salines in southern California: California Div. Mines Bull. 170,

chap. 8, p. 5-14. 

Wentworth, C. K., 1922, A scale of grade and class terms for clastic sediments:

: Jour. Geology, v. 30, p. 377-392. 

Wright, L. A., and others, 1953, Mines and mineral deposits of San Bernardino

County, Calif.: California Jour. Mines and Geology, v. 49, p. 49-259.
112 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION :

CORE LOGS

Bristol drill hole 2 . .

: [52 percent of core recovered]

Unit ......

Depth thickness .

(feet) (feet) Description . 

. 1.8 .1.8 Salt and dark yellowish-brown (10 YR 4/2) clay and silt; 

porous sponge of crystalline salt composing about 70 percent of material; clay contains limy nodules % in. thick; 

puffy salt-encrusted silt at surface.

2. 8 1.. 0 Clay and silt, moderate olive-gray (5 Y 4/2) and dark yellowishbrown (10 YR 4/2), massive; contains disseminated small 

salt crystals and small limy specks. .... 

4.7 1.9 No core. . 

6.0 1.3 Clay, moderate olive-gray, massive; contains salt crystals and

limy nodules and layers. 

6. 5 .5 Clay, silt, and very fine sand, moderate yellowish-brown

(IQYR 5/4) and dark yellowish-brown (1QYR 4/2). 

8.3 1.8 Clay, moderate olive-gray (5F 4/2), and salt.crystals; salt

about 25 percent. . 

11. 5 3. 2. Salt, impure, and olive-gray clay and silt; principal commercial

bed; saturated with brine rich in calcium chloride. 

19. 5 8. 0 No core.

20.0 .5 Clay, silt, and very fine sand, yellowisbrbrown (10 YR 5/2); 

contains scattered salt crystals (25 percent).

24. 1 4. 1 No core.

25. 0 .9 Clay and silt, dark yellowish-brown (10YR 4/2), and pale

yellowish-brown (10F/2 6/2) biotitic very fine sand; contains

scattered salt crystals (20 percent). 

28. 8 3. 8 No core. 

30.0 1.2 Clay, grayish-olive (10 Y 4/2), and salt, in equal amounts;

fine to coarse sand grains throughout clay. 

. 34. 0 4. 0 No core.

35.0 1.0 Clay, gray-green; contains small salt crystals and fine sand

. grains throughout. . . ' 

37. 7 2. 7 No core. 

40.0 2.3 Clay, gray-green; contains small salt crystals and fine sand

grains throughout. 

43.0 3.0 No core.

45.0 2.0 Clay, gray-green; contains small salt crystals and1 fine-sand 

, grains throughout.

49. 0 4. 0 No core.

50. 0 1. 0 Clay, gray-green; contains small salt crystals and fine sand 

grains throughout.

51. 0 1.0 No core.

55.0 4.0 Clay, gray-green; contains small salt Crystals arid fine sand 

grains throughout; : ' : 59. 1 .4. 1 No core. ,

60. 0 .9 Sand, fine, green and brown.

69. 1 9. 1 No core.

70. 0 .9 Clay, sandy; contains small salt crystals.

76. 1 6. 1 No core.

80. 0 3. 9 Salt crystals in clay.
CORE iiO(3S FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 113

Bristol drill hole 2 Continued

Depth

(feet) (feet) Description

85. 6 5. 6 No core.

90. 0 4. 4 Clay, green, and brown silt, laminated; contains flecks and 

	pods of anhydrite.

94. 5 4. 5 No core.

100.0 5. 5 Clay, green, and brown silt, laminated; contains some salt

	crystals; with massive salt bed 0.4 ft thick.

105.6 5.6 No core. , .

107. 0 1. 4 Silt, brown, and salt crystals.

110. 0 3. 0 Salt crystals in reddish-brown clay.

113. 8 3. 8 No core.

120. 0 6. 2 Clay and silt, reddish-brown; contains some salt crystals..

128.4 8.4 No core. . ..

130.0 '" 1. 6 Silt, brown, and fine granular gray salt. .

138. 3 8. 3 No core.

140.0 1.7 Clay, gray; lies above salt crystals in clay.

146. 2 6. 2 No core.

150.0 3.8 Clay, green; contains some salt. . 

152.3 2.3 No core. ' 

155. 6"' 2.7 Salt, very fine granular and crystalline. 

162.3 7.3 No core. . 

165.0 2.7 Salt, massive. . . 

169.7 4.7 No core. ; . ' 

172. 0 2. 3 Salt, massive and as crystal clusters, and well-bedded grayish- 

	brown clay and silt. 

176. 8 4. 8 No core.

180. 0 3. 2 Clay, silty, brown, laminated, and crystalline salt.

183. 0 3. 0 No core.

185. 0 2. 0 Silt, clayey, brown, laminated, and crystalline salt.

191. 0 6. 0 No core.

193.0 2.0 Salt, massive. .

198. 5 5.5 No core. ...

200. 0 1. 5 Salt, massive.

206. 6 6. 6 No core.

210. 0 3. 4 Clay, gray; contains some salt and flecks of anhydrite.

216.3 6.3 No core.

220.0 3.7 Salt, massive. . .

227. 6 7. 6 No core.

230. 0 2. 4 Clay, sandy, grayish-green; with thin salt layers at base,

237. 0 7. 0 No core.

240. 0 3. 0 Clay, sandy, green, and salt layers. '

245. 7 5. 7 No core.

250. 0 4. 3 Clay, brown, laminated; interbedded with thin salt layers..

254. 7 4. 7 No core.

260. 0 5. 3 Salt, massive; with some brown clay layers.

263. 6 3. 6 No core.

267. 0 3. 4 Salt, massive; with some brown clay layers.

27-2. 8 5. 8 No core.

277. 0 42 Clay, sandy, brown and some green, laminated; with several

	salt layers. 

283. 6 6. 6 No core.
114

Bristol drill hole 2 Continued

Unit Depth thickness (feet) (feet) Description

287. 0 3. 4 Clay, sandy, brown, laminated; with several salt layers.

. 287. 4 .4 No core.

290. 0 2. 6 Salt, massive.

297. 1 7. 1 No core.

298. 0 . 9 Salt, massive.

300. 0 2. 0 Salt layers, thin; interbedded with gray plastic clay.

302. 0 2. 0 No core.

305. 0 3. 0 Salt, massive.

310. 5 5. 6 Clay, dark-brown, compact; contains some salt.

315. 0 4. 5 No core.

318. 0 3. 0 Clay and sand, dark-brown; contains some salt.

320! 6 2. 6 No core.

323. 0 2. 4 Salt, massive; with some dark-brown clay and sand.

327. 3 4. 3 No core.

330. 0 2. 7 Salt, massive; with some dark-brown clay.

330. 3 . 3 No core.

336. 0 5. 7 Salt, massive.

340. 8 4. 8 No core.

. 343. 0 2. 2 Clay, dark-brown, massive; contains salt in lower part.

347. 4 4 4 No core.

350. 0 2. 6 Salt, massive; with some dark-brown clay.

356. 6 6. 6 No core.

359. 0 2. 4 Clay, brown, laminated.

360. 0 1. 0 Salt, massive.

364 4 4 4 No core.

366. 0 1. 6 Clay, brown, and salt.

367. 0 1. 0 Salt, massive.

369. 2 2. 2 No core.

370. 7 1. 5 Salt, massive, above brown clay.

372. 0 1. 3 Clay, yellowish-brown, laminated.

375. 8 3. 8 No core.

380. 0 42 Clay, brown, laminated.

383.6 3.6 No core.

385. 0 1. 4 Salt, broken; with some clay.

390. 7 5. 7 No core.

395. 0 43 Clay, brown, hard, laminated; with salt seams.

403. 2 8. 2 No core.

404 5 1. 3 Clay, brown, hard, laminated.

405.0 .5 Salt,massive.

405. 5 . 5 No core.

411. 0 5. 5 Clay, dark-brown, compact, plastic.

415. 1 41. No core.

417. 0 1. 9 Clay, buff (WYR 7/2), laminated.

421. 3 4 3 No core.

424 5 3. 2 Salt, massive, and brown plastic clay.

427. 1 2. 6 No core.

428. 0 . 9 Salt, massive.

429. 5; .. 1. 5 Clay, brown.

430. 0 . 5 Salt, massive.

431. 5 1. 5 Clay, buff (10YR 7/2), laminated.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALEF. 115

Bristol drill hole 2 Continued

Unit

Depth thickness

(feet) (feet) . Description

432. 5 1.0 Clay, brown, interbedded with salt beds 2-6 in. thick.

437. 0 4. 5 No core.

440. 0 3. 0 Clay, brown, interbedded with salt layers 2-6 in. thick.

447! 9 7. 9 No core.

450. 0 2. 1 Clay, brown, interbedded with salt.

453. 3 3. 3 No core.

456. 0 2. 7 Clay, brown, interbedded with salt.

459. 5 3. 5 No core.

463. 0 3. 5 Clay, brown, interbedded with salt layers 2-6 in. thick.

465. 8 2. 8 No core.

468. 0 2. 2 Clay, gray and brown, laminated, interbedded with salt

	layers 2-12 in. thick. 

470.4 2.4 No core. :

473. 0 2. 6 Salt in layers 2-12 in. thick; with some brown laminated clay.

480. 1 7. 1 No core.

483. 0 2. 9 Clay, gray and brown, laminated, interbedded with salt

	layers 2-12 in. thick. 

487. 5 4. 5 No core.

490. 0 . 2. 5 Clay, brown, and salt layers; salt predominates in lower part.

497. 0 7. 0 No core.

500. 0 3. 0 Salt and clay, interbedded.

503. 6 3. 6 No core.

507. 0 3. 4 Clay with some salt; may be slumped material in part.

508. 5 1. 5 No core.

516. 0 7. 5 Salt, pure, massive; with very little clay.

520. 5 4: 5 No core.

525. 0 4. 5 Clay, brown, laminated.

532. 4 7. 4 No core.

535. 0 2. 6 Clay, brown, over massive salt.

538. 4 3. 4 No core.

541. 5 3. 1 Salt, massive.

545. 0 3. 5 Clay, brown.

552. 3 7. 3 No core.

553. 7 1. 4 Clay, brown.

. 555. 0 1. 3 Salt and brown clay; salt 60 percent.

561. 7 6. 7 No core.

562. 6 . 9 Mud; probably slumped material.

563. 8 1. 2 Clay, brown.

565. 0 . 1. 2 Salt, massive.

571. 4 6. 4 No core.

572. 7 . 1. 3 Salt, white, massive.

573. 4 . 7 Salt, green, granular.

574. 3 . 9 Clay, brown.

575. 0 . 7 Clay and salt.

577. 1 2. 1 No core.

580. 0 2. 9 Salt, massive.

583. 5 3. 5 No core.

585. 7 2.2 Clay, brown. . :

586. 0 . 3 Salt, massive.

590. 5 4. 5 No core.
116 , GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Bristol drill hole 2 Continued

Unit

Depth thickness 

(feet) (feet) > . Description

598. 4. . 7. 9 Clay,:dark-brown, compact, laminated.

598.8 .5 Salt.

599..5 . 6 V Clay, brown. '

600. 0 . 5 Salt.

608.0 8.0 Salt with some clay.

613.0 5.0 Clay, brown, compact. .

618. 0 5. 0 Salt, crystalline to massive; with some clay.

620. 0 2. 0 Clay, brown, compact.

622. 8 2.8 No core. ...-.- . .

626. 2 3. 4 Clay, brown, compact.

327.0 ,8 Salt, crumbly, and clay.

628.2 1.2 No core. .

637.0 8.8 Salt, mostly massive; with some clay. '

. 637. 6 .6 Salt, massive.

639. 5 1. 9 Clay, brown.

649. 5 10. 0 Clay and salt, intermixed, and massive salt interbedded with 

	thin stringers of brown clay.

651. 4 1. 9 Salt, massive.

 657. 0 5. 6 Clay and salt, intermixed, and massive salt interbedded with 

	thin stringers of brown clay.

658. 5 1. 5 Salt, massive; with less than 10 percent clay.

658. 8 . 3 Clay, brown, silty.

659.8 1.0 Salt, pure, massive. : : 662. 5 2. 7 Salt, with about 20 percent green and brown clay.

662. 8 . 3 Silt, grayish^olive' (10F 4/2); contains about 20 percent salt.

664. 3 1. 5 Salt, massive; with 20 percent brown and green silty clay.

666. 9 2. 6 Clay, moderate yellowish-brown (WYR 5/2); contains small 

	tan limestone nodules.

667. 0 . 1 Tuff, white; composed of glass shards.

673. 3 6. 3 No core.

676. 5 3. 2 Clay, brown (WYR 5/2), massive; with flecks of anhydrite 

	at 678 ft.

677. 0 . 5 Salt and green clay, in equal amounts.

680. 6 3. 6 No core.

685. 9 5. 3 Clay, dark-brown (WYR 3/2) and moderate-brown (WYR

	5/2), massive; with 1 salt bed 1 in. thick. '. 

687. 0 1. 1 Salt, massive; with less than 5 percent green and brown clay.

691. 4 4. 4 No core.

692. 1 . 7 Salt and green and brown clay, in equal amounts.

693. 3 1. 2 Clay, brown (1QYR 5/2).

694. 9 1. 6 Salt with about 10 percent green and brown clay.

697. 0 2. 1 Salt and 30 percent green ^ clay; presence of calcium chloride 

	suggested by dampness of core after drying for 4 yr.

698. 6 1. 6 No core.

707. 0 8. 4 Salt, massive; with less than 5 percent brown and green clay.

707. 7 . 7 No core.

710. 5 2. 8 Salt, pure, massive.

714. 9 4. 4 Clay, brown (107^ 5/2), (WYR 5/4) and some green (10Y 6/2).

717. 0 2. 1 Salt with less than 20 percent brown clay.

719. 6 2. 6 Salt, massive; with 5 percent green clay.
CORE 1,068'FROMiBRISf OL, CADIZ, AND DANBY DRY LAKES, CALIF. 117

Bristol drill hole 2 Continued

Unit

Depth thickness 

(feet) (feet) Description '' '

720. 0 0. 4 Clay, green, and salt, in equal amounts.

720. 1 . 1 Limestone, argillaceous.

726.0 5.9 Clay, brown, massive.

727. 0 1.0 Salt, massive, and green clay; salt about 60 percent.

730. 6 3. 6 Salt, massive; with several green clay seams 4 in. thick.

734. 6 4. 0 Salt, massive.

736:6 2.0 : Clay, brown; with salt vein. 

739. 8 3. 2 No core.

745.0 5.2 Clay, brown, massive; with :flecks of anhydrite and 3 salt

:: beds each 1 in."thick. 

747. 0 2. 0 Salt, massive and crystalline; with .20 percent brown clay and

	5 percent green clay. 

749. 3 2. 3 No core. 

750.3 1. 0' Clay, brown, laminated: 

756. 2 5. 9 Salt, partly massive; with green clay. 

757. 0 . 8 Clay, green and brown, and salt.

759. 1 2. 1 No core.

762. 6 3. 5 Clay, brown, and salt crystals 1/16 to 1 in- thick; salt less;

'' ' ' ! ' '' than 50 percent of core.

764. 8 2. 2 Salt, granular and massive; with less than 5 percent green clay..

767. 0 ' ; 2. 2 Clay, dark-brown, massive and in part fissile; with 5 percent

	salt crystals 1-2 in. thick. 

772.0 ' ' 5.0 No core. 

777. 0 6. 0 Clay, brown; some weakly fissible; with 0.7 feet salt.

782. 1 6.1 No core.

 782. 9 " .'8' Mud, distorted; probably slumped material.

783. 9 1.0 Clay, brown, and mud; poor core, possibly slumped material..

784. 3 . 4 Salt crystals 1 in. thick.

785. 9 1. '6 Clay, dark-green, massive; with 3 salt beds each 2 in. thick.

786. 8 .9 Clay, brown, massive; with salt crystals % to 1 in. thick.

787. 0 .2 Salt, crystalline; with less than 10 percent green clay.

792. 3 5. 3 No core.

794. 8 2. 5 Clay, brown, weakly fissile; with flecks of anhydrite in last half

	foot.

"797. 0 2. 2 Salt, crystalline; with 20 percent green clay.

802. 4 5. 4 No core.

804. 0 1. 6 Salt, crystalline; with 10 percent green clay.

804. 9 '. 9 Clay, fine sandy, brown.

805. 1 . 2 Salt crystal.

806. 8 1:7' Clay, brown, weakly fissible.

807. 0 . 2 Salt, fine granular and massive; clayey, green; bitter taste.

808. 8r 1.8 No core.

811. 3 2. 5 Mud, brown; disordered, probably slumped material.

814. 6 3: 3 Clay, brown, massive; with tan limy nodules and a salt crystal 

	layer, 1 in. thick, in green clay.

815. 0 . 4 Clay, banded gray-green and black.

815. 3 . 3 Salt, massive.

815. 7 .4 Clay, brown, massive; contains a small limestone nodule.

816.5 .-8 Clay, green, massive. 

817. 0 . 5 Salt, massive.
118 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION?

Bristol drill hole 2 rContinued

Unit

Depth thickness 

(Jeet) (feet) Description

819.8 2. 8 ,-, No. core. 

821.0 1. 2 .Salt; massive.

822. 3 1. 3 Salt, broken; with brown clay, containing J4-in. crystals and 

grains of salt.

822. 8 . 5 Clay, brown grading to green, massive.

823. 7 . 9 Clay, green, massive; contains salt crystals 1 in. thick. 

827. 0 3. 3 ... Clay, brown, missive; contains limy nodules throughout.

831. 6 4. 6 No core.

832. 4 . 8 Mud, brown; probably slumped material.

834 0 1. 6 Clay, brown, massive; contains very few salt crystals % in.

thick.

837. 0 3. 0 Salt, massive; with green clay seams. 

839. 2 2. 2 No core.

842. 0 2. 8 Mud, brown, soft; probably slumped material. 

845. 3 3. 3 Salt, crystalline; with seams of brown clay.

847. 0 1. 7 Salt, crushed and broken, in brown clay.

848. 7 1. 7 No core.

849. 6 . 9 Mud, brown, soft; probably slumped material.

851. 7 2. 1 Salt,: crystalline -weakening to crumbly..at^bettomisless than 

1 percent brown clay.

852. 7 1. 0 Clay, mixed brown and green; contains embedded salt crystals 

% to 1 in. thick.

854. 8 2. 1 Clay, brown, massive; with salt seams and crystals.

855. 0 . 2 Clay, green, and salt, in equal amounts.

856. 5 1. 5 Clay, brown, massive; with 2 salt seams 1 in. thick.

857. 0 . 5 . Clay, mixed brown and green, and massive to crumbly salt, 

in equal amounts.

859. 2 2. 2 No core.

860. 2 1. 0 .Mud, brown, soft; probably slumped material. 

864. 2 40 Clay, brown, massive; with salt crystals and seams and a few 

 small stringers of green clay; also contains tan limy nodules

between 861.0 and 861.5 ft. 

867. 0 2. 8 Salt, crystalline; with brown clay seams.

872. 9 5. 9 No core.

873. 3 . 4 Salt, granular and massive; with green sandy clay of bitter

taste.

873. 5 .2 Clay, brown, massive. 

874 2 . 7 Salt, massive; with 5 percent green clay; unbroken salt cube

2% by 2>i in. . . 

874 9 . 7 Salt; with 20 percent green sandy clay of bitter taste. 

875. 4 . 5 Clay, brown, massive.

877. 0 1. 6 Clay, brown, massive, and broken salt, in equal amounts. 

882. 2 5. 2 No core.

885. 6 3. 4 Salt, massive; with less than 5 percent of green clay.

886. 1 . 5 Salt, broken. 

886. 3 . 2 Clay, green.

886. 5 . 2 Salt, crushed.

887. 0 . 5 Clay, brown, massive; contains 10 percent salt crystals. 

887.4 .4 Mud, brown, soft; probably slumped material..
CORE L01GS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 119

Bristol drill hole % Continued

Unit

Depth thickness 

(feet) (feet) . Description

. 893..4 ,... 6. 0 .Clay, brown, massive; with salt crystals at 888.0, 888.4, and 

891.3 ft.; contains light-tan.limy-nodules:at 889.0 and 890.0 

ft.; granular salt at 892.6 and 893X) ft.

. 897. p 3. 6 Clay, brown and green, finely interlayered with salt, in equal 

, . amounts.

902. 0 .5. 0 Salt, massive; with less than 1 percent green clay.

903. 0 1. 0 Clay, brown and green, interlayered with salt; in equal

.,-,..,.. , . amounts. 

907. 0 4. 0 Clay, brown, massive; contains limy nodules JS in. across at

903.2 ft.; contains salt crystals % in. thick at 904.2, 904.4,

904.6 and between 904.8 and 905.0 ft.; vein of salt % in.

thick extends vertically upward 2 in. into brown clay. 

912. 0 5. 0 No core. 

912. 7 . 7 Salt and green clay. 

916. 1 3. 4 Clay, brown, weakly fissile; contains limy nodules % in. across

at 914.5 ft.

917i 0 : '. 9 Salt, crushed, and green clay, contorted and compressed. 

921. 6 4.6 No core.

926. 3 , 4. 7 ;rr:Mud, brown, soft, contorted; probably slumped,material. 

926^ 6 : ' : ? 3-'Clay, mixed brown and green. ./ . ' 

926; 9 . 3 Salt, massive; with some brown clay.

927. 0 ; .1 Salt; finely crushed in drill bit. 

932. 4 '6: 4 ; No core.

934. 7 2. 3 Mud, brown, soft; probably slumped material.

935. 3 .6 Clay, brown.

937. 0 ' ' 1.7 Salt, massive, and brown clay; in equal amounts; poorly cored. 

942. 5 6. 5 No core.

945.3 2.8 Mud, soft, contorted; probably slumped material. 

' 947. 0 1. 7 Salt, massive and crystalline, finely ground, and contorted

brown clay.

.952.0 . ^5. O..Np,.core.

954.8 2. 8 Mud, soft, contorted; probably slumped material. 

957.0 2.2 Salt, massive and crushed, and brown clay; in equal amounts;

core disordered. 

962. 0 5. 0 No core. 

962. 3 . 3 Mud and salt; broken core; pieces of salt and green clay

suggest loss of salt.

966. 7 4. 4 Clay, green, brown, dark-brown, and almost black; with small 

veinlet of salt.

967. 0 .3 Salt, massive.

974. 5 7. 5 No core.

975; 1 .6 Clay, brown, massive.

975. 3' ' Y2 Salt, pure, massive.

976. 8 1. 5 Clay, brown, massive; with green fissile shale in plates 1 mm 

' thick.

977. 0 . 2 Salt, massive; piece held in drill bit.

981. 6 4. 6 No core.

983.1 1.5 Clay, brown; with thin green clay layer at top.

984. 1 1.0 Clay, brown; contains 5 percent salt crystals.

986. 2 2. 1 Clay, brown; contains numerous limy nodules in lower half.
120 GEOLOGIC INVESTIGATIONS : ': IN MOJAVE DESERT' REGION : 

Bristol drill hole # Continued unit ' ' ' '.:'... . . Depth thickness . , '.' '.-' 

(feet) (feet) Description

987. 6 ' ' 0. 8 Clay/ green; contains about 5 percent Salt and about 5 percent

',-' - flecks of white clay mineral or anhydrite. 

993.0 6.0 No core.

'997. 0 ' 4. 0 Clay/brown, weakly fissile^andimassi-V^^oatkiha^salt crystals; 

scattered throughout; tuffaceous(?) material at 994.0 and. 

994.4 ft; green micaceous layers at 995.0 aM 995.7 ft: 

1,003.5 '6.5 No core. : 

1, 006. 1 2. 6 Clay, brown; contains salt crystals in green clay patches, limynodules, and specks of white anhydrite. 

1,007.0 .9 Salt and green clay.

 ' Cadiz drill hole 1

[47 percent of core recovered] .. Unit ' .. v . < ... 

Depth thickness . . . 

(feet) (feet) Description

1.4 1-4 Sand, medium, fine, and very fine, yellowish-brown; with 

salt as crystals, crystalline masses, and as ^.surface crust; 

with gypsum as a crystal sand.

8.0 6. 6 Clay, grayish-olive (10F 4/2) jd^Qsej-interlayered.with porous 

salt .and gypsum sand. .

9. 0 1. 0 Salt, massive, coarsely crystalline; probably saturated with 

brine rich in calcium chloride as core is still damp after 

drying for 4 yr. . . .. .

16. 5 7. 5 No core.

18. 8 2. .3 Clay, green and brown, contorted; contains about 20 percent 

salt crystals. ;:

19. 0 .2 Sand, fine, light-gray and medium-gray; presence of calcium

chloride suggested by dampness of core .after drying for

4 yr. ., ,. ' 

24. 7 5. 7 No core. 

26.1 1.4 Clay, gray-green, dense; with light-brown (5\YR 5/6) clay

... stringers. . . : :-- ..- 

27. 2 1. 1 Sand, fine, granitic; contains streaks of gypsum. 

29. 0 1. 8 Clay, dark-brown; contains "fishtail">g$psum crystals # to %

in. long. . : 

37^ 6 & 6 No core. 

.39. 0 1. 4 Clay and silt, light- and medium-brown; contains gypsum

globules.

46.3 7. 3 No core. 

46. 8 .5 Clay and silt, dark blackish-green and light: brownish-green;

contains masses of 1-mm gypsum crystals. ,

48. 7 1. 9 Silt and fine sand, light gray-green; contains gypsum grains 

. and crystals. . \

49. 0 .3 Gypsum, very fine granular to fine-granular, white with gray 

streaks. . . .. .

58. 0 9. 0 No core.

59. 2 1. 2 Sand, fine, light gray-green, gypsiferous. : . 

59. 8 .6 Clay, dusky yellowish-brown (10Y72 2/2).-, ;' = . '=
CORE LpjGS'FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CAM?. 121

Cadiz drill hole 1 Continued

Unit

Depth thickness . . Meet) (feet) -^ . Description ' ".:'

60. S0 ..., Q. 2 .Silt, light-tan (1QYR 6/4); with a tarigle-of "fishtail".gypsum

crystals.

67.5 7.5 No core. : 

:.68.2.. ....- ,.7 Sand, fine, yellowish-brown. . . ;

68. 4 ... 2 Gypsum, powdery.

68.6 . 2 Sand, fine, yellow-brown. ; 

69.,8 . : v 1.2 Clay, brown; with 1-in. layer of tangled gypsum crystals,. 

70. 0 .2 Sand, very >fine to medium, light-tan.

:; 79.3 9.3 No core. . - 

80. ,0 .7 Clay, brown, interbedded with fine sand and powdery gypsum. 

85. 0 . 5. 0 No core.

90. 0 5. 6 Clay, brown, interbedded with fine sand and gypsum; with a 

. , ...... . - conspicuous 2-in. flinty white layer at 89.6 f,t. composed of

montmorillonite and finely granular halite with a trace of 

-~ sylvite. 

93. 7 3. 7 No core.

100.,0. . .6. 3 Clay, brown; contains limy patches and nodules toward 

bottom and fine sand and scattered gypsum crystals 

throughout.

106. 9 6. 9 No core.

107. 1 .2 Sand, medium, quartz; contains gypsum flakes.

108. 0 .9 Clay, brown.

108.8 .8 Sand, fine; with #-in. gypsum layer.

110. 0 1. 2 Clay, brown.

118. 9 a 9 No core.

119.3 .4 Clay, brown.

119. 7 .4 Gypsum and fine quartz sand.

120.0 .3 Clay, "brown.

129.0 9.0 No core;

129. 4 .4 Sand, fine, brown; contains sparse 1-mm quartz grains.

130. 0 .6 Gypsum crystals; with a few tan limy nodules.

139. 5 9. 5 No core.

140. 0 5 Clay, brown; with crystalline gypsum. 

.140. 4 . 4 No core. 

140. 8 .. 4 Clay, brown; 

>' :il$E>3; .5 Gypsum, medium-granular and as crystals; contains 1-mm

quartz grams. 

.143. 3. 2. 0. Clay, brown; contains some gypsum.

145. 8 2. 5 Sand, fine, brown; contains coarse quartz grains and gypsum 

flakes and crystals.

146. 6 . 8 Silt, brown; contains coarse quartz grains and gypsum.

149. 1 2. 5 Sand, very fine to medium, brown; contains coarse quartz 

. . grains.

150. 0 . 9 Sand, very fine, brown; contains coarse quartz grains and

gypsum.

.152. 1 2. 1 No core. ' 

158.'8 ; 6. 7 Sand, brown; ranging from very fine sand containing'coarse

quartz grains to coarse sand in thin lenses; with %-in. layer

of biotite flakes at 155.6 ft.
122 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Cadiz drill hole 1 Continued

Unit . - ' Depth thickness , .

(feet) (feet) Description

160.0 1.2 Clay, moderate-brown (5YR 4/4), very dense; contains tart

limy patches; distinctive unit. 

165. 7 5. 7 No core. 

171. 1 5. 4 Clay, moderate-brown (5YR 4/4), dense; contains light-grayand light pinkish-rbrown limy nodules; distinctive unit. 

171. 2 . 1 Sand, fine, brown and gray. 

171:4 .2 Clay, medium- to dark-gray, thinly laminated; with limonitte

ochre'between the laminae %-mm thick* 

208. 4 37. 0 No core. 

210. 0 1. 6 Sand, fine to very fine, moderate orange-brown (1QYR 6/4);

poorly consolidated; with 1-in. chocolate-brown clay seam. 

218. 6 & 6 No core. 

220. 0 1. 4 Sand, fine, quartz, moderate orange-brown (IQYR 6/4), poorly

consolidated.

228. 6 & 6 No core.

229. 1 . 5 Sand, fine, quartz, poorly consolidated.

229. 7 . 6 Clay, gray-brown, dense; with thin seams of yellow rusty fine 

sand.

230. 0 . 3 Sand, fine, yellow, rusty; with laminae of clay.

237. 8 7. 8 No core.

238. 9 1. 1 Sand, fine to very fine, poorly consolidated.

239. 6 . 7 Clay, gray-brown; with thin seam of light-gray silt.

239. 8 . 2 Sand, very fine, rusty.

240. 0 . 2 Clay, light-gray, limy, very hard.

245. 8 5. 8 No core.

250. 0 4. 2 Clay, medium-gray, dense; interlayered with tb;£ds of light

grayish-brown silt. ' ' 

256. 0 6. 0 No core.

256. 6 . 6 Clay, gray-brown, dense; slickensided fracture dips 57°. 

256.8 .2 Clay, dark red-gray, dense; dips 28°, possibly due to drag

from movement on above fracture. 

257. 4 . 6 Clay, greenish-gray. 

260. 0 2. 6 Clay, brownish-gray, dense; with light-gray silt seams and

several limy layers. 

263. 9 3. 9 No core.

267. 9 4. 0 Clay, dark-brown, very dense; with soine light-gray silt layers,

268. 2 . 3 Silt, light-gray, and dark-brown clay.

268. 5 . 3 Limestone, greenish-gray (5GY 6/1), hard; fossil foraminifers,. 

ostracodes, and abundant Chard.

269. 2 . 7 Silt and clay, finely laminated.

269. 4 .2 Limestone, greenish-gray (5GY 6/1), hard; sparse fossil Chara.

269. 7 .3 Clay, dark-brown; contains %-in. limy nodule; no fossils.

270. 0 . 3 Silt and very fine sand, brown aiid light gray-brown, finely

interbedded. 

273. 7 3. 7 No core.

279. 4 5. 7 Silt, pale yellowish-brown (IQYR 6/2) finely inter;b,ed,dfd;lnd 

crossbe'dded with dark yellowish-brown (id Y7J 4/2); contains sparse clay seams.

280. 0 . 6 Clay, dark-brown, dense; with lighter brown silt seams. 

280. 7 . 7 No core.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 123

Cadiz drill hole 1 Continued

Unit Depth - thickrfess »' . ' ' 

(feet) (feet) Description

285. 3 : 46 Silt interbedded with clay, pale to dark yellowish-brown,

crossbedded. 

288. 6 3. 3 Clay, dark-brown, massive.

288. 8 . 2 Silt, light-brown; contains one nonfossiliferous pale yellowishbrown (10 YR 6/2) hard limestone nodule.

289. 3 . 5 Clay, sandy, medium-brown, nonbedded; contains some limy 

splotches; sparsely fossiliferous, with 1 mollusk(?) shell Yio 

in. long.

289.6 .3 Clay, silty, medium-brown; weakly fossiliferous; contains %-in. 

lenses of dark-brown clay having a hackly appearance.

290. 0 . 4 Clay, sandy, medium-brown; contains 1 hard tan limestone 

nodule ^ in. thick.

294. 9 4. 9 No core.

296.7 1.8 Clay, dark-brown, blocky and massive, weakly laminated; 

contains 1 fossil gastropod shell 1 mm long..

297. 7 1. 0 Clay, medium-brown, granular, nonbedded; contains gypsum.

299. 1 1. 4 Silt, dark to pale yellowish-brown, thinly laminated.

299.4 ' .3 Clay, .moderate olive-gray (5V 4/2), dense. - .

300. 0 ' . 6 Silt, light to dark yellowish-brown, thinly laminated; contains pods of medium-brown clay.

306. 3 6. 3 No core.

310. 0 3. 7 Clay, sandy, medium-brown; no bedding.

313.5 3.5 Clay, dark-brown (10 YR 3/2), massive; contains gypsum vein 

% in. thick with green clay borders.

315. 7 -2. 2 Clay, brown, also mottled brown and green.

315. 9 .2 Clayj silty, green; contains'dear coarse quartz grains and has 

a bitter salty taste.

318. 4 2. 5 Clay, mottled brown and green, also dense brown; contains 

coarse and very coarse quartz grains.

318. 8 .4 Gypsum, aggregate of large crystals.

319. 8 1. 0 Clay, brown; contains scattered gypsum crystals throughout.

320. 5 .7 Clay, brown, massive; contains 2 very hard but shattered

limestone nodules. 

327. 0 6. 5 No core. 

327. 7 . 7 Clay, mottled green and brown, dense and massive.

329. 6 1. 9 Clay, brown, dense.

330. 0 . 4 Clay, mottled green and brown; with 1-in. bed of very fine

sand and silt. 

333. 4 3. 4 Clay, dark yellowish-brown (WYR 4/2), massive, interbedded

with silt.

333. 5 ..1 Limestone, light gray-green, hard; abundant fossil Chara. 

333. 8 . 3 Clay, silty, grayish-green (10GY 5/2); abundant fossil Chara. 

335. 0 1. 2 Clay, brown; contains moderately abundant fossil Chara in

green clay blotches; spots and flecks of anhydrite. 

335. 2 . 2 Gypsum, fibrous, asbestiform bed.

335. 7 . 5 Clay, sandy, brown; contains medium to coarse sand grains. 

337. 6 1. 9 Clay, brown, dense.

340. 0. 2. 4 Silt, light- and dark-brown; thinly color laminated. 

345. 2 5. 2 No core.
124 /.GEOLOGIC^INYBSTIGATIONS IN MOJAVE DESJEBT REGION ; ;;,

Cadiz drill hole 1- Continued

Unit

Depth thickness 

(feet) (feet) . Description ...

.. 349.2. 4.0 Silt, medium yellowish-brown; not color.laminated; gypsum

seam % in. thick.

350.0 .8 Clay, dark-brown, dense; with lighter, brown silt laminae. 

355.9 5.9 No core. . \ 

356. 5 . 6 Clay, brown, dense; mottled with green clay containing sparse

fossil spicules and shells. 

358.6 2.1 Clay, reddish-brown and olive-brown, dense, blocky; no

fossils. 

359. 0 . 4 Clay, brown mottled with green, dense; contains sparse fossil

Char a in green clay. 

360.0 1.0 Clay, dark yellowish-brown, dense. : < .' .

360. 7 . 7 Clay, medium-brown, very dense, blocky.

361. 9 1. 2 Clay, brown, massive; contains medium, coarse, and very 

coarse sand grains. . ;

362. 1 . 2 Silt, finely laminated; contains %-in. layer of powdery gypsum.

363. 0 . 9 Clay, light-brown (5YR 5/6), dense, blocky. :

364 7 1. 7 Silt, clayey, light-brown, and dark-brown silty clay.

365. 0 . 3 Clay and silt, medium bluish-gray (5B 5/1) and greenish^gray

(5GY 6/1), calcareous; contains gypsum, both powdery and

as crystals,- and fossil Chara. 

368. 3 3. 3 Clay, light-brown (5YR 5/6) and moderate-brown, dense;

contains scattered coarse quartz grains and sparse fossil

Chara in green clay blotches.

368. 6 . 3 Limestone nodule, pale greenish-tan, hard; lies between walls 

of abundantly fossiliferous (Chara) green clay.

369. 8 1. 2 Clay, dark-brown and light-brown (5YR 5/6); contains sparse 

fossil Chara in green clay areas.

370.0 .2 Limestone nodules, medium orange-tan (10Y7Z 6/4); contain 

biotite flakes and quartz grains; no fossils.

370. 6 . 6 No core.

373. 3 2. 7 Clay, sandy, brown; sparse fossil Chara.

376. 4 3. 1 Silt, alternating light.and dark yellowish-brown, finely interbedded with light-brown (SYR 5/6) blocky clay.

378.7 2.3 Clay, sandy, medium-brown. : 379. 4 .7 Silt, light and dark yellowish-brown.

379.9 .5 Clay, dark-brown, dense. i

380. 0 . 1 Silt, light and dark yellowish-brown.

386. 5 6. 5 No core.

387. 7 1. 2 Clay, brown, dense; with areas of mottled green and brown 

clay containing Chara and gastropods.

389. 9 2. 2 Silt, dark-brown, well-bedded.

390. 0 . 1 Limestone nodule, light-brown, hard.

390. 7 . 7 No core. ;

391. 4 . 7 Clay, brown with green patches; contains K-in. gray-green 

hard limestone nodule; all sparsely fossiliferous (Chara).

392. 9 1. 5 Silt and clay, medium- to dark-brown.

393. 2 . 3 Clay, olive-brown, very dense. 

394 3 1. 1 Clay, brown; with medium sand.

395. 1 . 8 Clay, slate-green and brown; contains thin gypsum vein and 

pale greenish-gray (5(7 F 7/1) limestone nodule.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 125

Cadiz drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

397. 5 2. 4 Clay, dark-brown, dense.

400. 0 2. 5 Clay, dark-brown, interbedded with lighter brown silt.

403. 3 3. 3 No core.

410. 0 6. 7 Clay, mottled and splotchy green and brown; sparse fossil

Chara; contains coarse sand lenses. 

420. 0 10. 0 Silt and silty clay, dark yellowish-brown (IQYR 3/2) and

moderate-brown (SYR 3/4), interbedded throughout with

mottled green and brown clay; brown clay contains sandy

layers.

423. 5 3. 5 No core.

424. 5 1.0 Silt, clayey, brown.

425. 4 . 9 Clay, dark-brown, very dense; with laminae of silt; dip of 

laminae 30° from horizontal.

426. 4 1.0 Silt interbedded with silty clay, dark-brown.

427. 0 . 6 Clay, brown; with sparse fossil Chara in green clay splotches. 

427. 1 . 1 Clay, olive-brown, very dense.

427. 2 . 1 Clay, moderate-browns (5YR 2/4 to SYR 5/4), very dense. 

427. 3 . 1 Sand lens, predominantly very coarse (up to 4 mm) but grading down to extremely fine.

427. 7 . 4 Silt, moderate-brown.

428. 7 1.0 Clay, moderate-brown (SYR 4/4), dense.

430. 0 1. 3 Clay, gray-green and dark-brown, limy; sparsely fossiliferous,

with brown chitinous spicule. 

430. 9 . 9 No core.

433. 3 2. 4 Clay, brown, dense; dip of bedding 30° from horizontal. 

433. 5 . 2 Clay, dark reddish-brown (WR 3/4), dense. 

437. 7 4. 2 Clay, sandy; sand grains all sizes up to 2 mm.

439. 2 1. 5 Clay, brown and green; sparse fossil Chara in green clay.

440. 0 . 8 Silt, brown. 

446. 4 6. 4 No core.

450. 0 3. 6 Clay, brown with green patches, dense; possibly slumped 

material.

458. 3 8. 3 No core.

459. 5 1. 2 Clay, brown, dense; contains sand grains.

460. 0 . 5 Limestone nodules, tan and green, extremely hard; green 

nodules contain fossil Chara.

466. 0 6. 0 No core.

467. 7 1. 7 Sand, fine; dampness of core after drying for 4 yr suggests it 

was saturated with calcium chloride.

470. 0 2. 3 Clay, light-brown (SYR 6/4) and dark-brown (IQYR 3/2) to 

pale yellowish-brown (IQYR 6/2) very dense, well-bedded.

471. 3 1. 3 No core.

473. 8 2. 5 Clay, brown and pale orange-brown (IQYR 7/2), dense; dip

about 35°. 

475. 6 1. 8 Clay, tan-brown; with light-gray and very light gray sandy

clay patches containing sparse Chare. 

480. 0 4. 4 Clay, medium to light orange-brown, very dense; with green

clay and limy clay splotches bearing deepest fossils (Chara)

found in this hole. 

480. 8 . 8 Clay, brown to brownish-gray, dense.
126 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Cadiz drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

488. 5 7. 7 Clay, light olive-gray (5Y 5/2) darkening to brownish-gray

(5YR 4/1) near bottom; with some lighter gray silt beds. 

490. 0 1. 5 Sand, very fine, light-gray; with thin clay seams. 

498. 4 8. 4 No core.

498. 8 . 4 Clay, brown, contorted.

499. 0 . 2 Limestone nodule, gray-green; no fossils.

500. 0 1.0 Silt and clay, light gray-brown.

Danby drill hole 1

[52 percent of core recovered] 

Unit

Depth thickness 

(feet) (feet) Description

4. 0 4. 0 No core. 

10. 5 6. 5 Silt, clayey, dark yellowish-brown (10 YR 4/2), calcareous,

salty; wormlike cavities stained by iron and manganese;

thin beds of fine sand in lower part. 

12. 3 1. 8 Gypsum, crystalline.

14. 0 1. 7 Silt, clayey, dark yellowish-brown (10 YR 4/2), calcareous, 

salty; as above but with less manganese stain and more iron 

stain.

15. 2 1. 2 Gypsum, crystalline; with calcareous and salty silt.

16. 2 1.0 Silt; as above but more clayey; contains thin beds of mica.

16. 4 .2 Gypsum, crystalline.

20. 0 3. 6 Silt; as above, but more clayey; contains thin beds of mica.

22. 5 2. 5 No core.

30. 0 7. 5 Silt, clayey, yellowish-brown (lOF/E 5/2), calcareous, salty,

massive; with thin bed of medium sand at 27.5 ft. 

37. 5 7. 5 No core. 

40. 0 2. 5 Silt, clayey, yellowish-brown (IQYR 5/2), calcareous, salty,

massive; thin bed of coarse sand at 39.5 ft. 

45. 5 5. 5 No core. 

50. 0 4. 5 Silt, clayey, yellowish-brown (IQYR 5/2), calcareous, salty,

massive.

53. 0 3. 0 Sand, fine, gray; grades to gray clayey silt. 

60. 0 7. 0 Sand, fine, clayey, and silty; contains many very coarse sand

grains and granules (up to 4 mm). 

62. 0 2. 0 No core. 

65. 0 3. 0 Silt, clayey, yellowish-brown (10 YR 5/2), calcareous, salty.

69. 5 4. 5 Sand, medium, silty, calcareous, salty.

70. 0 .5 Clay, silty, calcareous, salty; some brown limestone.

72. 5 2. 5 No core.

74. 0 1. 5 Sand, medium, silty.

78. 0 4. 0 Silt, clayey, dark yellowish-brown (10 YR 4/2).

79. 0 1.0 Sand, fine, silty.

80. 0 1.0 Clay, silty, yellowish-brown (IQYR 5/2), calcareous, salty. 

89.5 9. 5 No core. Probably unconsolidated dark yellowish-brown

(IQYR 4/2) calcareous silty clay.

90. 0 .5 Limestone, brown, and poorly cemented mudstone. 

93. 0 3. 0 No core.
 CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 127

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

97. 5 45 Silt, clayey, moderate yellowish-brown (5YR 5/4), calcareous, 

salty.

98. 0 .5 Sand, medium, silty, light-brown (SYR 6/4), calcareous.

99. 0 1.0 Sand, medium; grades to silty clay.

100. 0 1.0 Clay, silty; interbedded with medium sand; both dark yellowish brown (10YR 4/2); well bedded.

104. 5 4. 5 No core.

105. 0 . 5 Clay, silty, dark yellowish-brown (IOYR 4/2), calcareous.

106. 5 1. 5 Sand, fine.

110. 0 3. 5 Silt, clayey, interbedded with fine sand; iron stains on sand

fillings; limestone nodules at 109.0 ft. 

118. 0 8. 0 No core. 

118.5 .5 Silt, clayey, dark yellowish-brown (10 YR 4/2); becomes more

clayey at 118.5 ft. 

120. 0 1. 5 Clay, dark yellowish-brown, interbedded with light olive-gray

(5 Y 5/2) clay.

128. 0 8. 0 No core.

129. 7 1. 7 Clay, silty, dark yellowish-brown (1QYR 4/2); mudstone fragment at 129.0 ft.

130. 0 . 3 Silt, greenish-gray (5GY 6/1), interbedded with light greenishgray (5GY 8/1) calcareous silt.

131. 5 1. 5 No core.

132. 5 1.0 Silt, light olive-gray (5Y 6/1), calcareous.

137. 5 5. 0 Sand, silty, calcareous, massive.

140. 0 2. 5 Silt, medium dark-gray (N 4), calcareous, thinly bedded, hard

and compact. 

144. 0 4. 0 No core. 

150. 0 6. 0 Silt, interbedded clayey and sandy, medium dark-gray (N 4).

158. 0 8. 0 No core.

159. 0 1.0 Silt, fine-sandy, massive.

160. 0 1.0 Clay, silty, calcareous, salty, thin-bedded.

169. 9 9. 9 No core.

170. 0 .1 Sand, fine, silty, banded grays.

177. 5 7. 5 No core.

178. 0 . 5 Sand, medium, silty, olive-gray (5Y 4/1).

179. 0 1.0 Sand, fine, silty, olive-gray (5Y 4/1).

180. 0 1.0 Silt, gray, and medium sand; both calcareous and nonsalty.

187. 0 7. 0 No core.

188. 5 1. 5 Sand, medium, silty; contains flattened nodules of clay.

190. 0 1. 5 Silt, finely interbedded with fine sand, both olive gray (5Y

4/1), calcareous. 

195. 0 5. 0 No core.

195. 3 . 3 Sand, fine, silty and clayey, olive-gray (5Y 4/1), massive.

196. 0 .7 Sand, medium, silty, olive-gray (5Y 4/1), massive.

199. 5 3. 5 Silt, clayey; contains cavities of medium sand.

200. 0 . 5 Sand, medium, silty, calcareous, slightly salty, well-bedded;

manganese stain on sand bedding. 

206. 0 6. 0 No core. 

. "208. 5 2. 5 Silt, clayey, olive-gray (5Y 4/1), calcareous; color banded.
128 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT RE'GION

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

209. 0 0. 5 Sand, medium, silty, olive-gray (5F 4/1), calcareous, thinlybedded.

210.0 1.0 Silt, clayey, olive-gray (5 Y 4/1), calcareous.

217. 0 7. 0 No core.

220. 0 3.0 Sand, fine, silty, interbedded and intergradational with 

clayey silt, both olive gray (5Y 4/1), calcareous, and nonsalty; thin bedding seen in clayey silt where clay and silt 

are of higher concentration.

227. 0 7. 0 No core.

227. 5 . 5 Silt, clayey, olive-gray (5F4/1), calcareous.

230. 0 2. 5 Sand, medium, calcareous.

235. 5 5. 5 No core.

240. 0 4. 5 Sand, medium, silty, olive-gray (5F 4/1), calcareous, massive; 

bed of clayey silt of same color at 236.0 ft.

247.0 7.0 No core.

250. 0 3. 0 Sand, medium, silty, olive-gray (5F 4/1).

257. 0 7. 0 No core.

257. 5 . 5 Sand, fine, silty, olive-gray (5F 4/1), calcareous; grades to 

coarse sand at 257.5 ft.

260. 0 2. 5 Clay, silty, olive-gray (5F4/1), calcareous, massive; contains 

cavities of coarse sand.

264. 5 4. 5 No core.

268. 0 3. 5 Sand, medium, silty, olive-gray (5F 4/1), massive, but with 

traces of bedding; carbonaceous (?) material at 268.0 ft.

270. 0 2. 0 Silt, clayey, olive-gray (5Y 4/1), calcareous; thinly bedded at 

269.0 ft; fissile along planes with smooth and highly 

polished surfaces dipping 45° to axis of core.

277. 0 7. 0 No core.

278. 5 1. 5 Sand, medium, silty, olive-gray (5F 4/1), calcareous, bedded:

limestone cuttings of pale orange-brown (10 FJ? 7/2) at

277.0 ft. 

280. 0 1. 5 Silt, clayey, olive-gray (5F 4/1), massive; medium sand at

279.5 ft. 

285. 0 5. 0 Sand, fine, silty, interbedded and intergradational with clayey

silt, both olive gray (5F 4/1), calcareous.

289. 0 4. 0 Sand, medium, silty, interbedded with clayey silt; distinct 

bedding; contains small inclusions of reddish-brown clay.

290. 0 1.0 Sand, coarse, olive-gray (5F 4/1), calcareous; volcanic cinders

at 289.0 ft.

296. 0 6. 0 No core. 

296. 5 .5 Clay, silty, thinly interbedded with fine sand, both olive gray

(5F 4/1); volcanic cinders at 296.5 ft. 

300. 0 3. 5 Clay, silty, olive-gray (5F 4/1), calcareous, massive; thin.

bedding at 297.0 ft. 

305. 0 5. 0 No core.

309. 8 4. 8 Silt, clayey, olive-gray (5F 4/1); bedding at 306.0 ft.

310. 0 .2 Gypsum, crystalline. 

320. 0 10. 0 No core.

320. 4 . 4 Gypsum crystals in pale yellowish-brown (lOFjR 6/2) clayey 

silt.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 129

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

322. 6 - 2. 2 Gypsum, crystalline.

323. 0 . 4 Gypsum, crystalline, in clayey silt; bedded.

327. 0 4. 0 Gypsum, crystalline, moderate yellowish-brown (10 YR 5/4)

clayey silt. 

330. 0 3. 0 Gypsum, crystalline, in calcareous pale orange-brown (1QYR

7/2) silty fine sand. 

333. 0 3. 0 No core.

339. 0 6. 0 Gypsum, crystalline, in calcareous moderate yellowish-brown 

silty fine sand; locally well-bedded; grades into silty clay at 

336.0 ft and 338.5 to 339.0 ft.

340. 0 1.0 Gypsum, crystalline. 

347. 0 7. 0 No core.

349. 0 2. 0 Clay, silty, olive-gray (5Y 4/1), calcareous; contains nodules 

of moderate yellowish-brown (10F.R 5/4) clay.

349. 8 . 8 Gypsum, crystalline, in clayey silt; becomes increasingly 

clayey with depth.

350. 0 . 2 Sand, fine, greenish-gray, calcareous. 

354. 5 4 5 No core.

359. 5 5. 0 Clay, silty, dark yellowish-brown (1QYR 4/2), calcareous; 

contains flattened clay nodules and gypsum crystals which 

increase in quantity with depth.

360. 0 . 5 Gypsum crystals in silty clay; with thin beds of clay.

364. 0 4. 0 No core.

370. 0 6. 0 Gypsum, crystalline, and bassanite in calcareous dark yellowish-brown (10YR 4/2) silty clay; quantity of gypsum increases with depth to completely gypsum at 370.0 ft. 

Bassanite at about 365 ft.

377. 5 7. 5 No core.

378. 0 . 5 Sand, silty, massive.

380. 0 2. 0 Gypsum, crystalline, in dark yellowish-brown (10 YR 4/2)

silty clay.

387. 5 7. 5 No core. 

390. 0 2. 5 Gypsum crystals and crystalline gypsum in slightly calcareous

dark yellowish-brown (1QYR 4/2) silty fine sand. 

397. 0 7. 0 No core. 

400.0 3.0 Silt, clayey, dark yellowish-brown (lOFjR 4/2), calcareous;

interbedded with gypsum crystals and crystalline gypsum. 

407. 0 . 7. 0 Gypsum, crystalline, in dark yellowish-brown (1QYR 4/2)

clayey silt; thin bed of dark-gray silt at 407.0 ft. 

410.0 3.0 Silt, clayey, light olive-gray (5«K 6/1); contains crystalline

gypsum.

411. 0 1.0 No core. 

420. 0 9. 0 Gypsum, crystalline, in calcareous yellowish-brown (IOYR

5/2) clayey silt; with fine sand at 410.0 to 411.0 ft. 

424. 0 4. 0 No core.

430. 0 6. 0 Gypsum, crystalline, in olive-gray (5V 4/1) salty clayey silt. 

434. 5 4. 5 No core.

440. 0 5. 5 Gypsum, crystalline, in salty olive-gray (5F 4/1) clayey silt.

441. 0 1.0 Sand, medium, silty.

443. 0 2. 0 Gypsum, crystalline, in clayey silt.
130 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Danby drill hole 1 Continued

Unit

Depth thickness 

(Jeet) (feet) Description

450. 0 7. 0 Silt, clayey, olive-green (5F 4/1), calcareous, salty; thin bed

of medium sand at 446.5 ft. 

452. 5 2. 5 Silt, clayey, bedded; fine sand and some biotite at 451.0 ft.

460. 0 7. 5 Gypsum, crystalline, in salty calcareous olive-gray (5Y 4/1)r 

silt.

461. 0 1. 0 No core.

464. 8 3. 8 Gypsum, crystalline, in slightly salty yellowish-brown (lOF/f 

5/2) clayey silt; gypsum concentration grades from 40 percent at 461.0 ft to 0 percent at 461.5 ft, then increases with 

depth to 80 percent at 464.8 ft.

465. 1 . 3 Gypsum, crystalline; contains stringers of clay and off-colored 

gypsum crystals giving a "marble cake" appearance.

465. 3 . 2 Gypsum, crystalline clusters, in salty yellowish-brown (10 YR 

5/2) clayey silt; gypsum about 60 percent.

466. 4 1.1 Silt, clayey, yellowish-brown (IQYR 5/2), salty; small amount 

of gypsum.

467. 3 . 9 Gypsum, crystalline, in salty yellowish-brown (10 YR 5/2) 

clayey silt; some thin-bedded clays.

470. 0 2. 7 Gypsum, crystalline; contains stringers of clay and offcolored gypsum crystals giving a "marble cake" appearance.

480.0 10.0 Gypsum, crystalline, in salty calcareous yellowish-brown 

(10YR 5/2) clayey silt; gypsum concentration varies from 

10 to 80 percent with average around 60 percent; at various 

zones silt grades to silty fine sand and gypsum decreases.

482. 5 2. 5 No core.

490. 0 7. 5 Gypsum, crystalline, and very little calcareous yellowishbrown (1QYR 5/2) silt; silt more abundant at 482.5, 483.6, 

484.7, and 485.7 ft; silt and off-colored gypsum crystals 

give a "marble cake" appearance.

492. 6 2. 6 No core.

500. 0 7.4 Gypsum, crystalline, and some slightly salty calcareous 

yellowish-brown (1QYR 5/2) silt; silt content high at 492.2, 

495.2, and 497.1 ft; overall gypsum 90 percent.

509. 0 9. 0 No core.

510.0 1.0 Gypsum, crystalline, with bassanite; contains 10 percent 

clayey silt.

512. 6 2. 6 No core.

519. 9 7. 3 Gypsum, crystalline, in salty calcareous olive-gray (5F 4/1) 

silt; gypsum occurs, in compact flattened nodules at points 

of highest concentrations.

520. 0 . 1 Sand, fine, interbedded with salty calcareous clayey silt, both

olive-gray (5 Y 4/1). 

527. 0 7. 0 No core. 

527.5 .5 Silt, clayey, pale yellowish-brown (10 YR 6/2); interbedded

with thin beds of green clay. 

528. 4 . 9 Sand, fine, clayey and silty; contains pockets of yellowish-gray

(5Y 8/1) sand, also yellow fine sand nodules bordered by

dark clay.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 131

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

528. 9 0. 5 Clay and fine sand of variegated color, including olive-gray 

(5Y 4/1), very light gray (N 8), and pale-red (10# 6/2) 

clay, and yellow calcareous salty sand; clay color at 528.9 

ft grades from olive gray (5Y 4/1) to dark greenish gray 

(5(774/1).

530. 0 1.1 Sand, medium, silty, light olive-gray (5F 5/2), calcareous, 

salty, massive; closer inspection of sand reveals applegreen clay coating on many of the sand grains.

535. 5 5. 5 No core.

536. 2 . 7 Sand, medium, silty, light olive-gray (5F 5/2), calcareous, 

salty, massive.

538. 8 2. 6 Silt, clayey, pale olive-gray (5Y 7/1), interbedded with olivegray (5F 4/1) clay; grades into massive salty slightly calcareous pale olive-gray (5Y 7/1) silty fine sand.

538. 9 . 1 Clay interbedded with sand; clay is pale olive gray (5Y 7/1), 

olive gray (5Y 4/1), and moderate orange pink (10R 7/4);, 

sand is yellow grading to brown and to nearly black at 

top and bottom.

539.2 .3 Sand, medium, silty, pale yellowish-brown (10 YR 6/2), calcareous, massive.

539. 3 . 1 Clay interbedded with very fine sand; clay is pale olive gray 

(5Y 7/1) and olive gray (5Y 4/1), calcareous; sand is dark 

yellowish orange (1QYR 6/6) with dark brown top and 

bottom.

539.7 .4 Sand, fine, clayey and silty, pale yellowish-brown (10 YR 6/2), 

calcareous.

539. 9 . 2 Clay interbedded with very fine sand; clay is pale olive gray 

(57 7/1) and olive gray (5Y 4/1), calcareous; sand is dark 

yellowish orange (10 YR 6/6) with dark brown top and 

bottom.

540. 0 . 1 Sand, very fine, silty, pale yellowish-brown (10F.R 6/2), calcareous.

541. 0 1. 0 No core.

542. 0 1.0 Silt, clayey, yellowish-brown (10 FR 5/2), calcareous, massive. 

545. 4 3. 4 Silt, clayey, yellowish-brown (1QYR 5/2), calcareous, poorly

consolidated and water-saturated (core slumped beyond

recovery); clayey section at 544.8 ft. contains nodule of

crystalline gypsum.

545. 8 . 4 Silt, clayey, yellowish-brown, calcareous. 

546.2 .4 Silt, clayey, yellowish-brown, calcareous, salty; containscavities filled by moderate yellowish-brown clay and medium,

sand. 

548.8 2.6 Sand, medium, silty, yellowish-brown, calcareous, salty,

massive.

549. 5 . 7 Clay and silty clay, calcareous, salty; variegated colors: 

bluish white (5B 9/1), olive gray (5Y 4/1), dark greenish) 

gray (50Y 4/1), pale pink (5RP 8/2), and light greenish, 

gray (5(7 8/1).

550. 0 .5 Sand, very fine, clayey and silty; grades into salty calcareousclayey silt interbedded with clay.
132

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

552. 5 2. 5 No core.

552. 7 . 2 Sand, fine, interbedded with calcareous clay; bedding distorted;

sand grains are coated green. 

555.0 2.3 Clay, pale grayish blue-green; thinly interbedded with volcanic

dust.

556. 4 1. 4 Clay, light-gray (N 7), calcareous, massive. 

556. 5 . 1 Clay, dark-brown; thin bed bordering slickensides. 

556. 9 . 4 Clay interbedded with calcareous moderately micaceous fine

sand; angle of bedding 20° from horizontal.

 560. 0 3. 1 Clay interbedded with calcareous clayey silt; massive clay 

containing cavities filled with fine sand between 558.6 and 

559.9 ft.

561. 0 1.0 Clay, and silty clay, color banded but generally yellowish gray 

(5F 8/1); pastel green and yellow also observed.

562. 0 1.0 Clay, yellowish-gray (5F 8/1), massive; with thin beds of 

pastel green and dark yellowish-orange (10 YR 6/6) clay.

562. 2 .2 Sand, very fine, brown, massive.

563. 0 . 8 Clay, dark greenish-gray (5G 4/1), massive.

564. 8 1. 8 Clay, light greenish-gray (5GY 8/1), massive; bed of very

fine sand between 564.4 and 564.6 ft. 

.568. 9 4. 1 Clay, light greenish-gray (5G 8/1), to greenish-black (5G 2/1),

lamellar; carbonaceous material containing pyrite at 565.2,

566.0, and 566.5 ft.

569. 9 1.0 Clay interbedded with silty very fine sand, both light greenish 

gray (5G 8/1).

570. 0 . 1 Limestone, clayey, lamellar; contains /4-in. bed of brecciated 

opaline shale.

576. 5 6. 5 No core.

577. 1 . 6 Shale, dark greenish-gray (5GY 4/1), calcareous, lamellar,

highly compact.

580. 0 2. 9 Clay, grayish-olive (107 4/2), calcareous, lamellar. 

583. 0 3. 0 No core.

583. 7 . 7 Clay, dark greenish-gray (5G 4/1), lamellar.

584. 7 1.0 Sand, very fine, dark greenish-gray (5C? 4/1), massive.

 589. 7 5. 0 Clay, dark greenish-gray (5G 4/1), lamellar.

590. 0 . 3 Sand, fine, dark greenish-gray (56- 4/1); contains carbonaceous

material. 

598. 2 8. 2 No core.

 600. 0 1. 8 Sand, very fine, silty, greenish-gray (5GY 6/1), calcareous, 

salty, massive.

605. 0 5. 0 No core.

610. 0 5. 0 Sand, very fine, silty, medium greenish-gray (5(? 5/1), calcareous, salty, faintly bedded; more compact clayey beds at, 

606.3 and 608.8 ft exhibit parting.

 613. 8 3. 8 No core.

 620. 0 6. 2 Sand, fine, silty, light greenish-gray (5GY 8/1), calcareous,

massive; micaceous fine sand partings. 

625. 0 5. 0 No core.

 629. 0 4. 0 Sand, fine, silty, dark greenish-gray (5GY 4/1), calcareous, 

massive.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 133

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

630. 0 1.0 Clay, light greenish-gray (50? Y 8/1), calcareous, massive.

639. 0 9. 0 No core.

640. 0 1.0 Sand, fine, silty, dark greenish-gray (50 Y 4/1), calcareous, 

massive.

646. 2 6. 2 No core.

647. 6 1. 4 Sand, fine, silty, dark greenish-gray (5GY 4/1), calcareous,, 

salty, massive.

647. 8 . 2 Clay, dark greenish-gray (56- Y 4/1), calcareous, lamellar.

648. 0 . 2 Sand, fine, silty.

648. 1 .1 Clay, dark greenish-gray (5GY 4/1), lamellar.

648. 5 . 4 Sand, fine, silty, dark greenish-gray (5GY 4/1), massive.

649.4 .9 Clay, dark greenish-gray (5GY 4/1), massive.

649. 5 . 1 Limestone, gray.

650. 0 . 5 Sand, fine, silty, dark yellowish-brown (10 YR 4/2), calcareous,

massive.

656. 4 6. 4 No core. 

658. 4 2. 0 Sand, fine, silty, olive-gray (5Y4/1), calcareous, massive.

658. 7 . 3 Sand, fine; grades in depth to gray silt then back to carbonaceous fine sand.

659. 8 1.1 Sand, fine, silty, olive-gray (5Y 4/1), massive.

660. 0 . 2 Silt interbedded with fine sand, [both olive gray (5Y 4/1). 

665. 0 5. 0 No core.

669. 2 4. 2 Sand, fine, silty, olive-gray (5Y 4/1), calcareous, massive.

670. 0 . 8 Clay interbedded with silty fine sand, both olive gray, calcareous.

679. 1 9. 1 No core.

680. 0 . 9 Clay interbedded with silty fine sand, both light gray.

681. 9 1. 9 No core.

687. 9 6. 0 Sand, fine.

689. 5 1. 6 Clay, laminated, thin-bedded.

689. 8 .3 Sand, fine.

690. 0 . 2 Clay, massive.

693. 0 3. 0 No core.

693. 5 . 5 Clay, sandy.

700. 0 6. 5 Sand; last 2 ft very slightly consolidated,

705. 8 . 5. 8 No core.

706. 4 . 6 Clay, multicolored, predominantly orange; may be slumped

material. 

710. 0 3. 6 Sand, fine.

717. 1 7. 1 No core.

718. 0 . 9 Clay, disordered and without form; probably slumped material.

719. 4 1. 4 Clay, disordered and with vertical bedding and fragments 

of sand; may be slumped material.

720. 0 . 6 Sand, fine, interbedded with dense, compact gray flinty clay;; 

contains some limestone.

728. 8 8. 8 No core.

729. 7 . 9 Clay, disordered; probably slumped material.

730. 0 . 3 Sand, massive.

731. 4 1. 4 No core.
134 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

740. 0 8. 6 Sand, fine, silty, interbedded with massive and lamellar 

clay; calcareous and carbonaceous at places; with micaceous 

partings; fossil ostracodes and foraminifers at 732.4 and 

738.4 ft and in addition, gastropods, pelecypods, and barnacles at 738.4 ft.

747. 5 7. 5 No core.

750. 0 2. 5 Sand, fine, interbedded with lamellar clay and massive silty 

clay; becomes highly limy at 750.0 ft.

'758. 6 8. 6 No core.

760. 0 1. 4 Sand, fine, clayey, interbedded and intergradational with 

clayey silt and clay, all dark greenish gray (5QY 4/1) and 

calcareous.

763. 0 3. 0 No core.

770. 0 7. 0 Clay, massive, bedded, and lamellar, interbedded with clayey 

silt, mostly pale bluish-gray (SB 8/1), all calcareous; clay 

lamellae greenish gray with fine lamellae of white carbonate 

material; limy beds at 757.0 and 758.3 ft.

772. 5 2. 5 No core.

780. 0 7. 5 Clay, massive, interbedded with clayey silt, both greenish 

gray (50Y 6/1) darkening to almost black at 774.0 and 776.5 

ft, calcareous.

780. 7 . 7 No core.

781. 5 . 8 Limestone, light-gray (N 7); no bedding; roller bit blocked. 

785. 0 3. 5 No core.

785. 3 . 3 Sand, fine, in hard sandy limestone, both light gray (N 7) J 

fine sand partings.

785. 5 . 2 Limestone, light-gray.

786. 2 . 7 Clay, massive and lamellar, interbedded with silty clay, both 

light gray; fossil ostracodes and foraminifera at 785.9 ft.

787. 5 1. 3 Limestone, light-gray.

790. 0 2. 5 Clay, massive and lamellar, grayish olive-green (5GY3f2),

carbonate-rich; strong hydrogen sulfide odor; core well

broken by roller bit.

798. 7 8. 7 No core.

799. 0 . 3 Clay, dark-gray (N 3), massive.

799. 3 . 3 Silt, thinly interbedded with carbonate-rich clay.

799. 8 . 5 Clay, greenish-gray (5GY 6/1), massive, highly compacted.

800. 0 . 2 Sand, coarse, clayey and silty; quartz is subangular to rounded, 

somewhat frosted suggesting it was windblown.

800. 5 . 5 No core.

801. 0 . 5 Silt, clayey, brown, massive.

801. 3 . 3 Clay, compact, fissile; contains pebble of dioritic rock.

804. 7 3. 4 Clay, silty, grading to silty fine sand, both pale yellowish 

brown (10 YR 6/2).

805. 0 . 3 Sand, fine, brown, green, and dusty white: colors alternating 

starting with white at top grading to green and then to 

brown, with series repeated several times.

807. 3 2. 3 No core.

 808. 8 1. 5 Silt, clayey, dark yellowish-brown; contains dark-blue clay 

nodules; probably slumped material.
 CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 135

Danby drill hole 1 Continued

Unit

Depth thickness 

(feet) (feet) Description

809. 4 0. 6 Sand, medium, slightly clayey; spotted with hematite stains.

810. 0 . 6 Sand, medium, dusty-white; interbedded with moderate olivebrown (5Y 4/4) clayey and silty fine sand; brown grades to 

reddish pink toward center of core.

:816. 7 6. 7 No core.

817.2 .5 Clay, silty, dark yellowish-brown (1QYR 4/2), massive; 

contains fragments of hard, compact clay.

820. 0 2. 8 Sand, medium, silty, moderate orange-brown (1QYR 6/4), 

massive.

«27. 5 7. 5 No core.

830. 0 2. 5 Sand, medium, silty, moderate orange-brown (1QYR 6/4), 

massive.

837. 0 7. 0 No core.

840. 5 . 5 Granodiorite boulder; some fragments brought up.

$46. 0 5. 5 No core.

:850. 0 4. 0 Clay and silt, disordered; probably slumped material; bottom 

0.8 ft contains broken fragments of granodiorite. Fossil 

foraminifers and carbonized wood fragment found in 

disordered material; source location indeterminate.

S58. 5 8. 5 No core.

859. 5 1. 0 Clay and silty clay, brown to blue-black, massive, disordered.

860. 0 . 5 Granodiorite fragments (driller believed he was forcing a

boulder ahead of the bit with mud as a lubricant) 

880. 0 20. 0 Gravel, primarily of granodiorite; recovered only fragments.

Danby drill hole 2

[60.7 percent of core recovered]

Unit

Depth thickness 

(feet) (feet) Description

5. 0 5. 0 No core.

8. 8 3. 8 Clay, silty, moderate yellowish-brown (WYR 5/4), calcareous, 

salty.

14. 0 5. 2 Clay, silty, calcareous, salty; more silty than above.

15. 0 1.0 Clay, silty, moderate yellowish-brown (10Y72 5/4), calcareous,

salty. 

25. 0 10. 0 Clay, silty, light-brown (5YR 5/6), calcareous, salty; contains

subangular grains of quartz (1 mm).

30. 0 5. 0 Clay, silty, light-brown (SYR 5/6), micaceous, calcareous, 

salty, massive.

31. 8 1. 8 No core.

33. 0 1. 2 Clay, silty, dark yellowish-brown (WYR 4/2), calcareous,

salty.

38. 0 5. 0 Clay, silty; more clayey than above and lighter in color. 

38. 3 .3 Sand, medium, poorly sorted. 

40. 0 1. 7 Clay, silty, light-buff, calcareous, salty. 

48. 0 8. 0 Clay, silty, massive; contains many cavities filled with fine

sand.

50. 0 2. 0 Clay, light-buff, massive. 

53. 3 3. 3 No core.
136 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Danby drill hole 2 Continued

Unit

Depth thickness 

(feet) (feet) Description

55. 3 2. 0 Clay, light-buff, calcareous, massive.

60. 0 4. 7 Sand, very fine, clayey; lenses rich in biotite.

63. 4 3. 4 No core.

70. 0 6. 6 Silt, clayey, calcareous, salty, massive; contains many rounded 

1- to 2-mm quartz grains.

76. 5 6. 5 No core.

80. 0 3. 5 Silt, clayey, light-buff, calcareous, massive.

86. 5 6. 5 No core.

90. 0 3. 5 Silt, clayey, light-buff, calcareous, massive.

96. 2 6. 2 No core. 

100.0 3.8 Silt, clayey, yellowish-gray (578/1), calcareous, massive;

sand-filled cavities at 97.0 ft. 

107. 2 7. 2 No core. 

110. 0 2. 8 Silt, clayey, yellowish-gray (5F 8/1), calcareous, massive.

118. 2 8. 2 No core.

119. 5 1. 3 Silt, clayey, yellowish-gray (5F 8/1), massive.

120. 0 . 5 Sandstone, medium-grained, well-cemented.

129. 0 9. 0 No core.

130. 0 1.0 Sandstone fragments and limy nodules containing calcitefilled vugs.

133. 0 3. 0 No core.

140. 0 7. 0 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive, 

142. 6 2. 6 No core.

150. 0 7. 4 Silt, clayey, light olive-gray (5F 6/1), calcareous, massive. 

158. 0 8. 0 No core. 

160. 0 2. 0 Silt, clayey, light olive-gray (5F 6/1), calcareous, massive.

169. 5 9. 5 No core.

170. 0 . 5 Silt, clayey, light olive-gray (5F 6/1), calcareous, massive;

faint bedding planes. 

175. 5 5. 5 No core. 

180. 0 45 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive:

not well sorted mineralogically. 

187. 0 7. 0 No core. 

190. 0 3. 0 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive.

199. 2 9. 2 No core.

200. 0 . 8 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive. 

204. 0 4. 0 No core.

207. 0 3. 0 Sand, light-brown (5YR 6/4,) massive, 

210. 0 3. 0 Sand, light olive-gray (5F 6/1), massive. 

212. 0 2. 0 No core.

. 220. 0 8. 0 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive; 

not well sorted mineralogically.

229. 0 9. 0 No core.

230. 0 1.0 Sand, very fine, light olive-gray (5F 6/1), calcareous, massive;

not well sorted mineralogically. . 

232. 0 2. 0 No core. 

250. 0 18. 0 Sand, very fine, clayey, light olive-gray (5F 6/1), calcareous,

massive; becomes more clayey with depth. 

260.0 10.0 Clay interbedded with silty clay, light olive-gray (5F 6/1),

calcareous, thinly bedded.
CORE LOGS FROM BRISTOL, CADIZ, AND DANBY DRY LAKES, CALIF. 137

Danby drill hole 2 Continued

Unit

Depth thickness 

(feet) (feet) Description

263. 0 3. 0 No core.

270.0 7.0 Clay, light olive-gray (5Y 6/1), brown at depth, massive,

bedded; grades downward to silty clay and to very fine sand. 

278. 0 8. 0 Silt, clayey, moderate yellowish-brown (10Y72 5/4), micaceous. 

281. 0 3. 0 Gypsum, crystalline, in clayey silt; gypsum 80 percent. 

290. 0 9. 0 Silt, clayey, moderate yellowish-brown (1QYR 5/4), micaceous;

contains a few gypsum crystals. 

293. 0 3. 0 No core.

299. 7 6. 7 Silt, clayey, light-buff, micaceous, calcareous.

300. 0 . 3 Gypsum, crystalline; 90 percent.

301. 0 1. 0 No core. 

301. 3 . 3 Gypsum, crystalline.

310. 0 8. 7 Gypsum, crystalline, in calcareous clayey silt interbedded 

with medium sand.

318. 0 8. 0 No core.

319. 0 1. 0 Silt, clayey, light-buff, calcareous; contains a few gypsum

crystals.

320.0 1.0 Gypsum, crystalline; 75 percent. 

326.5 6. 5 No core. . 

330. 0 3. 5 Clay and silt, disordered; with 0.2 ft crystalline gypsum and

bassanite interbedded with clay. 

332. 5 2. 5 No core.

332. 9 . 4 Pebbles of limestone and biotite-rich diorite.

333. 9 1. 0 Gypsum, crystalline, in coarse sand.

338. 0 4. 1 Sand, fine, thinly interbedded with silt.

340.0 2.0 Sand, fine, silty, grading to fine gravel, both light brown (5 YR

6/4), calcareous. 

346. 5 6. 5 No core.

350. 0 3. 5 .Sand, very fine, and silt, both light brown (5YR 6/4), calcareous; faint bedding planes.

351. 4 1. 4 No core; drill struck boulder.

351. 5 . 1 Sandstone, medium- to coarse-grained; loosely cemented with 

calcareous cement.

352. 0 . 5 No core.

352. 4 . 4 Silt and clay, both calcareous, massive.

352. 8 . 4 Sand, medium, dark yellowish-brown (10Y.R 4/2).

353. 3 . 5 Sand, fine, dark yellowish-brown (10F.R 4/2).

360.0 6. 7 Sand, fine, interbedded with clayey silt, both moderate

yellowish brown (1QYR 5/4). 

364. 0 4. 0 Sand, fine, silly; grades to silt at depth.

364. 7 . 7 Sand, very fine, highly carbonaceous.

365. 5 . 8 Sand, fine, silty, and clay; sand is moderately reactive in dilute

cold hydrochloric acid, but clay is not reactive. 

370. 0 4. 5 Sand, very fine; grades to silt at depth. 

373. 8 3. 8 No core.

380. 0 6. 2 Clay, massive and compact, grading to fine sand and back to 

compact clay at bottom, all greenish gray (5GY 6/1) and 

slightly calcareous.

381. 5 1. 5 No core.

381. 8 . 3 Sand, very fine, clayey, poorly sorted.
138 GEOLOGIC INVESTIGATIONS IN MOJAVE DESERT REGION

Danby drill hole 2 Continued

Unit

Depth thickness 

(feet) (feet) Description

382. 4 0. 6 Clay, silty, extremely compact.

383. 6 1. 2 Clay, silty; disordered.

384. 8 1. 2 Clay, very fine sandy, extremely compact.

390. 0 5. 2 Sand, fine, silty, grading to medium sand at depth, both lightolive gray (5Y 5/2); poorly sorted.'

391. 0 1. 0 No core.

391. 2 .2 Pebble of volcanic rock 1^ in. across; light-brown lava with 

phenocrysts of epidote and hornblende.

393. 0 1. 8 Silt, clayey, faint-red to greenish-gray, massive, compact;. 

contains limy nodules and large quartz grains.

394. 3 1. 3 Clay, disordered fragments.

395. 0 . 7 Clay, faint-red to greenish-gray, massive, extremely compact^

396. 0 1.0 Clay, disordered fragments.

397.0 1.0 Clay, light-brown (5YR 5/6) to greenish-gray (5GY 6/1) r 

extremely compact; fossil foraminifers.

398. 6 1. 6 Clay, disordered.

399. 0 . 4 C'ay, light olive-gray (5F 5/2), calcareous, nonsalty, extremely compact; stained by'iron'oxide.:- -

400. 0 1. 0 Clay, disordered fragments, and massive clay at 400.0 ft.

406. 0 6. 0 No core.

407. 0 1. 0 Clay, green, calcareous, massive.

409. 8 2. 8 Clay, calcareous, massive and hard; contains limy nodules at 

409.4 ft.

410. 0 . 2 Sand, very fine, moderate-brown (SYR 4/4).

420. 0 10. 0 Clay, moderate-brown (5YR 4/4), massive; contains light-buff

limy nodules. 

425. 5 5. 5 No core. 

430. 0 4. 5 Silt, clayey, light-gray to medium-gray to brownish-red; gradesto fine sand at depth; cavities filled with micaceous fine sand;

quartz grains 1-4 mm distributed throughout core. 

435. 5 5. 5 No core.

438. 0 2. 5 Sand, very fine, light-brown, calcareous, massive. 

440. 0 2. 0 Clay, fine sandy, variegated colors; vugs with calcite crystals;

fossil ostracodes, foraminifers, and Chara. 

443. 0 3. 0 No core. 

445. 0 2. 0 Silt, clayey, disordered; contains distorted limy nodules and'

cavities filled with limy fine sand; bedding 3^4 mm thick in

more clayey sections. 

449. 0 4. 0 Clay, silty, light-brown, massive; grades to clay of variegated

colors and then to clayey fine sand with depth.

449. 2 . 2 Clay and fine sand, both light buff; abundant fossil gastropods, 

pelecypods, foraminifers, Chara, and a barnacle.

450. 0 . 8 Sand, fine, light-gray, massive. 

453. 0 3. 0 No core.

460. 0 7. 0 Sand, very fine, very pale yellowish brown (10 YR 7/2), massive; becomes more clayey at several zones with depth.

o