1

QUATERNARY GEOLOGIC MAP OF DALLAS

4° x 6° QUADRANGLE, UNITED STATES

QUATERNARY GEOLOGIC ATLAS OF THE UNITED STATES

MAP I-1420 (NI-14)

State compilations by

Kenneth V. Luza, Kathryn M. Jensen, William D. Fishman, 

E. G. Wermund, Jr., and Gerald M. Richmond

Edited and integrated by

Gerald M. Richmond and Ann Coe Christiansen

1994

NOTE: This map is the product of collaboration of the Oklahoma Geological Survey. the Texas Bureau of 

Economic Geology, and the U.S. Geological Survey, and is designed for both scientific and practical purposes. 

It was prepared in two stages. First, separate maps and map explanations of that part of each State included in 

the quadrangle were prepared by the State compilers. Second, these maps were integrated and locally 

supplemented by the editors; map unit symbols were revised to a uniform system of classification; and map 

unit descriptions were prepared from information received from the State compilers and from additional 

sources. Differences of mapping or interpretation in different areas were resolved by correspondence to the 

extent possible; most simply reflect differences in available information or differences in philosophies of 

mapping and serve to encourage further investigation. Richard M. Pratt plotted the volcanic ash locality 

symbols and prepared the index map of eolian sand and loess distribution.

Less than forty percent of the surficial deposits of the United States have been mapped and described. 

Traditionally, mapping of surficial deposits has focused on glacial, alluvial, eolian, lacustrine. marine, and 

landslide deposits. Slope and upland deposits have been mapped in detail only in restricted areas. However, an 

enormous amount of engineering construction and many important problems of land use and land management 

occur in regions of extensive slope and upland deposits (colluvium and residuum, for example). These 

materials have many different physical characteristics. Therefore, an effort has been made to classify, map, and 

describe these deposits on the basis of published and unpublished subsoil data, distribution and structure of 

bedrock parent materials, slope, and unpublished interpretations of individuals. An attempt has been made to 

show the gradual change that takes place from east to west across Oklahoma and Texas from acid soils and 

predominantly chemical weathering products (decomposition residua) to calcareous soils and predominantly 

mechanical weathering products (disintegration residua). The classification is crude, but represents a first step 

toward a more refined and useful product.

For scientific purposes, the map differentiates Quaternary surficial deposits on the basis of lithology,

texture, genesis, stratigraphic relationships, and age, as shown on the correlation diagram and indicated in the 

map unit descriptions. Geomorphic features are not distinguished as map units, and terraced alluvial deposits 

along streams are broadly grouped in time because of the impossibility of mapping them individually at a scale 

of 1:1,000,000.

For practical purposes, the map is a surficial materials map. Materials are distinguished on the basis of 

texture, composition, and local specific characteristics such as swelling clay. It is not a map of pedologic or 

agronomic soils. Rather it is a generalized map of soils as recognized in engineering geology, or of subsoils or 
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parent materials from which pedologic and agronomic soils are formed. As a materials map it serves as a base 

from which engineering, land-use-planning, or land-management maps can be derived. However, it does not 

replace detailed site study and analysis.

The map contains the following illustrations:

An index map to the International Map of the World 1:100,000 topographic series showing the Quaternary 

geologic map of the Dallas 4°x 6° quadrangle and other published maps of the Miscellaneous 

Investigations Series (I–1420).

An illustration showing the responsibility for State compilations.

An illustration showing the correlation of map units.

An illustration showing eolian sand and loess thickness and distribution in the map area

LIST OF MAP UNITS

HOLOCENE AND LATE WISCONSIN

asa ALLUVIAL SAND, SILT, CLAY, AND GRAVEL

ale ALLUVIAL SILT AND CLAY

afa ALLUVIAL-FAN DEPOSIT

es EOLIAN SHEET SAND

ed DUNE SAND

HOLOCENE TO ILLINOIAN

asi ALLUVIAL, LACUSTRINE, AND EOLIAN DEPOSIT

oc PLAYA CLAY

cga CALCRETE-CLAST LOAM TO SANDY LOAM COLLUVIUM

cbf BOULDERY SANDY COLLUVIUM

cbm LIMESTONE-CLAST LOAMY COLLUVIUM

cbo LIMESTONE-CLAST SILTY CLAY COLLUVIUM

cse RED SILTSTONE- AND SHALE-CLAST LOCALLY GYPSIFEROUS LOAMY COLLUVIUM

csf PEBBLY SANDY CLAY LOAM COLLUVIUM

csi QUARTZ SANDSTONE-CLAST SANDY COLLUVIUM

csj LIMESTONE-, SHALE-, SANDSTONE-, AND CALCRETE-CLAST LOAMY COLLUVIUM

cla SANDSTONE- AND SHALE-CLAST COLLUVIUM

clf ACID SHALE-CHIP CLAY-LOAM COLLUVIUM

cll SHALE- AND SLABBY LIMESTONE-CLAST COLLUVIUM

clm SHALE- AND SILTSTONE-CLAST LOAMY COLLUVIUM

clq SANDSTONE- AND SHALE-CLAST LOAMY COLLUVIUM

clt SHALE-CLAST CLAYEY COLLUVIUM

ccj LIMESTONE- AND SANDSTONE-CLAST LOAMY COLLUVIUM

xba SHALE- AND LIMESTONE-CLAST DISINTEGRATION RESIDUUM

xsb QUARTZ SAND DISINTEGRATION RESIDUUM

xlc RED SILTY CLAY DISINTEGRATION RESIDUUM

xld RED SILTY CLAY DISINTEGRATION RESIDUUM AND GYPSUM SOLUTION RESIDUUM

xle FINE SANDY LOAM DISINTEGRATION RESIDUUM

xlg CALCAREOUS SANDY LOAM DISINTEGRATION RESIDUUM

xcb CALCAREOUS CLAY DISINTEGRATION RESIDUUM

xcc STONY SELENITIC SILTY CLAY LOAM DISINTEGRATION RESIDUUM

xcd SANDSTONE AND MUDSTONE CLAY LOAM DISINTEGRATION RESIDUUM

LATE PLEISTOCENE

oca LACUSTRINE CLAY, SILT, AND SAND

LATE PLEISTOCENE TO MIDDLE PLEISTOCENE

afc ALLUVIAL- AND SHEETWASH-FAN FINE SAND AND SILT
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aso CEMENTED ALLUVIAL GRAVELLY SAND

afb ALLUVIAL-FAN GRAVELLY TO SANDY LOAM

LATE PLEISTOCENE TO EARLY PLEISTOCENE

asg ALLUVIAL GRAVEL, SAND, SILT, AND CLAY

esa EOLIAN SHEET SAND

cab CEMENTED COLLUVIUM2 AND SHEETWASH ALLUVIUM

MIDDLE PLEISTOCENE AND EARLY PLEISTOCENE

ago ALLUVIAL GRAVEL AND SAND

ocb EOLIAN AND ALLUVIAL SAND, SILT, AND CLAY

PLIOCENE

occ LACUSTRINE SAND, CLAY, AND LIMESTONE

QUATERNARY AND TERTIARY

zsa LIMONITIC SANDY DECOMPOSITION RESIDUUM

zsb QUARTZ SAND DECOMPOSITION RESIDUUM

zsd SANDY DECOMPOSITION RESIDUUM

zse CLAYEY SAND AND SANDY CLAY DECOMPOSITION RESIDUUM

zsp FINE SANDY, SILTY CLAY DECOMPOSITION RESIDUUM

zld CLAYEY SILT TO SILTY CLAY DECOMPOSITION RESIDUUM

zlq FINE SANDY LOAM DECOMPOSITION RESIDUUM

zlr CLAY LOAM AND FINE SANDY LOAM DECOMPOSITION RESIDUUM

zls SANDY CLAY LOAM DECOMPOSITION RESIDUUM

zlt RED CLAY LOAM DECOMPOSITION RESIDUUM WITH LOCAL GYPSUM RUBBLE

zcb SMECTITIC CLAY DECOMPOSITION RESIDUUM

zcc SILTY CLAY DECOMPOSITION RESIDUUM

zcg SAND, GRAVEL, SILT, AND CLAY DECOMPOSITION RESIDUUM

zcj CLAY AND SILTY CLAY DECOMPOSITION RESIDUUM

zcn SANDY CLAY LOAM DECOMPOSITION RESIDUUM

zri SILTY CLAY DECOMPOSITION RESIDUUM AND CHERTY CLAY SOLUTION RESIDUUM

zrj CLAY LOAM AND CHANNERY LOAM DECOMPOSITION RESIDUUM AND SOLUTION 

 RESIDUUM

rcn CHERTY CALCAREOUS CLAY SOLUTION RESIDUUM

rcv STONY CALCAREOUS CLAY SOLUTION RESIDUUM

usa FELDSPATHIC SANDY FINE GRUS

LIST OF MAP SYMBOLS

CONTACT

SHORELINE

FAULT WITH QUATERNARY DISPLACEMENT—Bar and ball on downthrown side

VOLCANIC ASH BEDS

Lava Creek B ash bed (Pearlette type O)

Huckleberry Ridge ash bed (Pearlette type B)

Pearlette family of ash beds not individually identified

Pleistocene, possibly belonging to Pearlette family of ash beds

Cerro Toledo ash bed (upper?)

Guaje ash bed in Blackwater Draw Formation

Mount Blanco ash bed in Blanco Formation
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DESCRIPTION OF MAP UNITS

HOLOCENE AND LATE WISCONSIN

asa ALLUVIAL SAND, SILT, CLAY, AND GRAVEL—Light-brown, gray, or grayish-brown sand, silt, 

and gravel intermixed or interbedded; commonly crossbedded. Locally includes lenses of clay and 

layers of sheetwash alluvium. In western part of mapped area, chiefly coarse quartzose sand 

containing lenses of subangular to well-rounded gravel. Clasts mostly calcrete derived from the 

Ogallala Formation (Miocene). Silt and clay become more abundant and gravel becomes finer and 

increasingly confined to lower part of deposit eastward across quadrangle. Quartzite, chert, 

limestone. and sandstone clasts also increase in abundance eastward in deposits of secondary 

drainages. Thickness 3–30 m; mostly 5–6 m 

ale ALLUVIAL SILT AND CLAY—Dark- to light-brown or gray silt, clay, and fine sand intermixed and 

interbedded; includes a few lenses of subangular to subrounded gravel, especially in lower part. 

Clasts chiefly chert and limestone 2–4 cm in diameter. Underlies flood plains and low stream 

terraces in northeast part of quadrangle. Mapped areas include some sheetwash alluvium. 

Thickness 0.5–10 m; locally as much as 20 m 

afa ALLUVIAL-FAN DEPOSIT—Yellowish- to brownish-gray gravel, coarse to medium sand, and minor 

silt, intermixed and interbedded; structureless to poorly bedded. Clasts chiefly angular to 

subrounded pebbles and cobbles of limestone, dolomite, and chert. Forms fans, chiefly in drainage 

of North and South Forks of Wichita River and Salt Fork of Brazos River. Thickness 2–8 m

es EOLIAN SHEET SAND—Gray to yellowish- or reddish-brown, medium to very fine sand; silty, 

slightly clayey; mostly quartz; minor feldspar. Distinguished as a map unit only in Texas. 

Commonly overlies an older alluvial deposit. Mostly stabilized by vegetation. Thickness 0.5–3 m

ed DUNE SAND—Gray to yellowish- or reddish-brown, fine to medium sand; locally silty or loamy. 

Mostly quartz and minor feldspar; well sorted; moderately to well rounded; generally 

noncalcareous. Forms dunes; relief as much as 5 m; mostly stabilized by vegetation. Commonly 

overlies older alluvial deposits. In Oklahoma, locally includes extensive sheet sand. Thickness 3–

30 m; generally about 7 m

HOLOCENE TO ILLINOIAN

asi ALLUVIAL, LACUSTRINE, AND EOLIAN DEPOSIT (Lingos Formation (Caran and Baumgardner, 

1990) in Texas)—Buff, grayish- to yellowish-brown or pale-red sequence of sediments spreading 

from eastern base of escarpment in western part of quadrangle. Sediments consist of basal sand and 

gravel overlain by lenses of calcareous, fossiliferous lacustrine clay and marl, and an upper deposit 

consisting of eolian sheet sand and channel deposits that are mostly eolian sand and silt interbedded 

with paleosols and alluvial silt, sand, and gravel. Locally overlies a paleosol developed on Permian 

siltstone. Basal gravel contains Rancholabrean vertebrate fauna. Youngest deposits probably early 

Holocene. Thickness characteristically 30–40 m; thickness varies abruptly and is as much as 75 m 

where deposit has filled depressions formed by collapse of the beds following dissolution of the 

underlying gypsum bedrock

oc PLAYA CLAY—Light-gray, light-grayish-brown to pale-brown, and brownish-gray sandy clay and silt; 

massive, calcareous; hard when dry, sticky and plastic when wet. Films, threads, and soft masses of 

calcium carbonate comprise about 5-8 percent of volume. Occurs in circular to oval closed 

depressions, many of which contain small intermittent playa lakes. Thousands of the depressions 

exist, most too small to show on map, but some in the northwest part of quadrangle are 100 m to 

several kilometers across. Many depressions, especially those in eolian sand, are formed by 

deflation and (or) dissolution of near-surface carbonate by infiltrating ground water. Others are 

formed by subsidence resulting from deep solution and collapse of underlying gypsum bedrock. 

Some depressions are rimmed by a low circular mound of brown loam about 1 m thick that overlies 

white indurated secondary calcium carbonate. The nearly flat surface of some deposits is 

characterized by pimple mounds and depressions (gilgai) of Holocene age. Thickness 0.5–5 m 
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cga CALCRETE-CLAST LOAM TO SANDY LOAM COLLUVIUM1

—Reddish- to yellowish-brown, 

brown, or gray mixture of gravel, sand, and clay. Poorly sorted; nonbedded to thin bedded. Clasts 

mostly pebble to cobble size; a few are boulders. Most are fragments of calcrete. Sand is fine to 

medium, quartzose; forms bulk of deposit; includes admixed silt and clay. Moderately cemented 

with calcium carbonate in places. Mantles slopes that dissect the Ogallala Formation (Miocene). 

Mapped areas include bedrock outcrops and small areas of locally derived alluvium. Thickness 

commonly less than 1 m; locally 2–4 m at base of slopes

cbf BOULDERY SANDY COLLUVIUMI

—Tan to brown, dark-grayish-brown, or yellowish-brown, fine 

sand, silt, and minor silty clay. Contains sandstone boulders; poorly sorted, nonbedded to thin 

bedded; some boulder fields at surface. Developed on moderate to steep slopes underlain by highly 

folded and faulted sandstone and shale. Mapped only in southeastern Oklahoma. Thickness 0.5–1.5 

m

cbm LIMESTONE-CLAST LOAMY COLLUVIUM1

—Dark-grayish-brown to light-brown, locally reddish 

brown, moderately alkaline clay loam and loam containing scattered to abundant, angular blocky to 

platy fragments of hard limestone, shale chips, particles of calcium carbonate cement, and, locally, 

sparse chert. Nonbedded to thin bedded. In places, rests in abrupt contact on hard, laminar calcium 

carbonate overlying limestone bedrock; elsewhere, the hard calcium carbonate is lacking and the 

loam, mixed with fragments, overlies fragmented limestone. On steep slopes, commonly contains 

more than 50 percent fragments and locally is a limestone rubble with very little matrix. Mapped 

areas include abundant bedrock outcrops. In valley bottoms, consists of angular to subangular stony 

sheetwash alluvium, but along valley of Red River is chiefly sandy to silty and thin bedded. 

Thickness on uplands 0.5–3 m; on moderate to steep slopes 0.1–1 m 

cbo LIMESTONE-CLAST SILTY CLAY COLLUVIUM1

—Reddish-gray to pale-reddish-brown sandy to 

silty clay containing abundant angular to subangular blocky clasts of limestone and chert;

nonbedded to locally thin bedded. In places characterized by elongate zones of limestone rubble 

parallel to slope; locally includes some sheetwash alluvium. Mapped only in Texas. Thickness 0.2–

1 m; may be thicker at base of slopes

cse RED SILTSTONE- AND SHALE-CLAST LOCALLY GYPSIFEROUS LOAMY COLLUVIUM1

—

Reddish- to grayish-brown, sandy silt loam to silty clay loam containing angular fragments of 

sandstone and siltstone, and slabs or chips of shale and thin-bedded dolomite. Abrupt contact with 

underlying rock. Includes zones of partly dissolved chunks and blocks of impure gypsum in a 

granular silty clay matrix and, in places, sheets of impure gypsum rubble. Clayey debris and rubble 

derived from beds of gypsum upslope that are undergoing mass wasting following former 

subsurface dissolution and collapse. Mapped areas include bedrock outcrops. Thickness 0.5–1 m

csf PEBBLY SANDY CLAY LOAM COLLUVIUM1

—Reddish-brown, pebbly, silty sandy clay containing 

fragments of sandstone, dolomite, and limestone. Nonbedded to thin bedded. Locally includes 

sheetwash alluvium. Quartz pebble lag at surface. On some uplands and slopes, overlies pink clay 

loam or zone of calcium carbonate accumulation. Mapped areas include extensive bare bedrock 

outcrops, commonly in the form of flatirons and dip slopes. Mapped only in Texas. Thickness 0.2–

1 m

csi QUARTZ SANDSTONE-CLAST SANDY COLLUVIUM1

—Pale-gray, yellowish- or reddish-brown, 

coarse, medium, and fine quartz sand, locally pebbly. Contains sandstone rubble clasts of assorted 

sizes, some limonite-cemented clasts, and, locally, some limestone and chert rubble derived from 

rock types upslope. Commonly in abrupt contact with underlying rock. Mapped areas include local 

bedrock outcrops. Occurs chiefly along eastern escarpment of High Plains in southwest part of 

quadrangle near south border. Thickness 1–5 m

csj LIMESTONE-, SHALE-, SANDSTONE-, AND CALCRETE-CLAST LOAMY COLLUVIUM1

—

Reddish- to yellowish- or pale-brown, sandy loam containing scattered angular to subrounded clasts, 

mostly limestone, shale, sandstone, and calcrete; a few pebbles of black chert and pink quartz. 

Locally forms a scree. Occurs near top of eastern escarpment of High Plains in southern part of 

quadrangle. Thickness 0.5–3 m

cla SANDSTONE- AND SHALE-CLAST COLLUVIUM1

—Very dark grayish brown to yellowish-brown 

silty clay, silt, and sand containing angular to subangular sandstone and shale fragments. 

Nonbedded to thin bedded. Developed on moderate to steep slopes. Mapped areas include sparse 

bedrock outcrops and patches of eolian sand. Mapped only in Oklahoma. Thickness 0.5–1.5 m
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clf ACID SHALE-CHIP CLAY-LOAM COLLUVIUM1

—Reddish- to greenish- or dark-grayish-brown, 

acidic, sandy to silty clay containing shale chips and subangular to well-rounded clasts of sandstone 

as much as 15 cm across. Mapped only in Oklahoma along east edge of quadrangle. Thickness 0.5–

1.0 m

cll SHALE- AND SLABBY LIMESTONE-CLAST COLLUVIUM1

—Very dark grayish brown to olivegray silt loam; local iron-manganese concretions. Dominant clay mineral is smectite; swells when 

wet; shrinks when dry. Locally overlies remnants of clayey residuum developed from shale in area 

of Arbuckle Mountains and uplands to east in Oklahoma. Downslope creep of shale exposed in 

places. Thickness commonly less than 1.6 m; thicker at base of slopes

clm SHALE- AND SILTSTONE-CLAST LOAMY COLLUVIUM1

—Reddish- to dark-grayish-brown silt 

loam to clay loam, weakly calcareous; creep of underlying shale visible locally. Present only in 

Oklahoma at base of uplands in north-central part of quadrangle. Thickness commonly less than 1 

m

clq SANDSTONE- AND SHALE-CLAST LOAMY COLLUVIUM1

—Reddish-brown to brown, very fine 

sand to silt containing clasts of red sandstone, siltstone, and shale; local dolomite and gypsum 

rubble in heads of some drainages. Nonbedded to thin bedded. Mapped areas include bedrock 

outcrops, local alluvium, and minor remnants of decomposition residuum (zlq). Thickness less than 

0.6 m

clt SHALE-CLAST CLAYEY COLLUVIUM1

—Yellowish-brown to gray clay to clay loam containing 

chips and slabs of red shale and, in places, angular fragments of limestone, dolomite, siltstone, red 

fine-grained sandstone, and gypsiferous rubble. Nonbedded to thin bedded. Abrupt contact with 

bedrock. Locally mantled with thin loess. Mapped areas include bedrock outcrops, minor alluvium, 

and small areas of decomposition residuum (zlt). Thickness generally less than 3 m; may be as 

much as 5 m at base of slopes 

ccj LIMESTONE- AND SANDSTONE-CLAST LOAMY COLLUVIUM1

—Dark-grayish- to reddish-brown 

silt loam to clay loam colluvium containing numerous scattered clasts of hard limestone and fine- to 

medium-grained sandstone. Occurs on slopes of Arbuckle Mountains and uplands to east in 

Oklahoma. Abrupt contact with patches of underlying residuum and bedrock. Mapped areas 

include bedrock outcrops and small patches of residuum developed on limestone and sandstone. 

Thickness less than 2 m 

xba SHALE- AND LIMESTONE-CLAST DISINTEGRATION RESIDUUM2

—Light reddish- to yellowishbrown silty clay loam containing abundant shale chips where developed over shale, and forming 

matrix of limestone rubble where developed over limestone. Locally includes some zones of 

dolomite and gypsum clasts. Grades down into parent rock. Underlies gently rolling uplands 

characterized by stair-step benches in which limestone underlies the bench surfaces and shale the 

frontal slopes. Mapped areas include bedrock outcrops and local limestone rubble or shale debris 

colluvium. Areas underlain by dolomite and gypsum commonly characterized by dissolution sinks 

and caves filled with collapsed rubbly residuum. Thickness less than 0.5 m to 1 m

xsb QUARTZ SAND DISINTEGRATION RESIDUUM2

—Pale-gray to reddish-yellow, coarse to medium 

quartz sand, locally silty; abundant muscovite; limonite stained in places. Includes angular 

fragments and chunks of sandstone. Grades down into sandstone bedrock through a fragmented 

zone, locally impregnated and cemented with calcium carbonate. Mapped areas include broad low 

dunes (ed) of Holocene age, remnants of calcium carbonate cemented residuum (zsb), colluvium 

(csi). and minor alluvium. Thickness 0.5–2 m

xlc RED SILTY CLAY DISINTEGRATION RESIDUUM2

—Orange-brown and red, mottled grayish-green,

silty clay; local fine sandy clay. Grades down abruptly into red shale or dolomite on gently sloping 

uplands. Mapped areas commonly include bedrock outcrops and, very locally, gravelly loam 

colluvium on dissected slopes. Gravel is derived from deposits of Seymour Formation (ago) 

capping divides immediately upslope. Thickness 0.5–1 m

xld RED SILTY CLAY DISINTEGRATION RESIDUUM2 AND GYPSUM SOLUTION RESIDUUM4

—

Reddish-brown, noncalcareous to highly calcareous silt loam to clay loam disintegrated from 

underlying shale, siltstone, and thin beds of dolomite. Includes blocky fragments or slabs of 

siltstone and chips of shale in lower part. Matrix in lower part also includes zones of grayishbrown, granular, silty to clayey gypsiferous rubble commonly less than 0.3 m thick derived from 

underlying thick beds of gypsum. Numerous sink holes resulting from subsurface dissolution and 
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collapse of the gypsum common. Mapped areas include bedrock outcrops and some colluvium 

(cse). Thickness generally less than 1.2 m

xle FINE SANDY LOAM DISINTEGRATION RESIDUUM2

—Reddish-brown to reddish-gray fine sandy 

loam, locally calcareous; contains soft carbonate concretions. Numerous red sandstone, siltstone, or 

shale fragments in lower part. Grades down through fragmented zone into fine-grained sandstone, 

siltstone, soft shale, or calcareous shale. Mapped areas include bedrock outcrops, colluvium,

sheetwash alluvium, and alluvium of local streams. Thickness commonly less than 1 m; as much as 

2 m where developed on soft rocks

xlg CALCAREOUS SANDY LOAM DISINTEGRATION RESIDUUM2

—Reddish-brown to brown, 

calcareous, fine sandy loam derived from underlying red, fine-grained sandstone, shale, and 

dolomite. Includes numerous relatively fresh rock fragments in lower part and grades down into 

bedrock through fragmented zone. Mapped areas include small deposits of locally derived 

colluvium, sheetwash alluvium, stream alluvium, and remnant patches of residuum (zls). Thickness 

0.5–1 m

xcb CALCAREOUS CLAY DISINTEGRATION RESIDUUM2

—Light-brown to brown or light-reddishbrown silty clay to fine sand containing chips of shale and small fragments of mudstone, siltstone, 

sandstone or coarse-grained limestone, on all of which the residuum is developed. Clay is 

calcareous and locally smectitic. Grades down into bedrock through a thin fragmented zone. 

Mapped only in Texas. Mapped areas include extensive unmapped, unconsolidated deposits of silt, 

sand, and gravel on uplands. Gravel ranges from pebbles to boulders. most of limestone, but some 

of quartz, quartzite, sandstone, or mudstone. Mapped areas also contain bedrock outcrops and 

colluvium. Thickness commonly less than 1 m; locally only 5 cm

xcc STONY SELENITIC SILTY CLAY LOAM DISINTEGRATION RESIDUUM2

—Brown to reddishbrown silty clay loam, locally sandy. Contains abundant rubble composed of dolomite, sandstone, 

mudstone, and partly dissolved gypsum clasts. Material grades through fragmented zone into 

underlying bedrock. No pronounced karst topography. Mapped areas include bedrock outcrops and 

rubbly colluvium. Present in Texas south of southwesternmost Oklahoma. Thickness 0.5–1 m

xcd SANDSTONE AND MUDSTONE CLAY LOAM DISINTEGRATION RESIDUUM2

—Yellowish- to 

light-reddish-brown clay loam to sandy clay loam containing abundant fragments of the underlying 

bedrock of mudstone, sandstone, shale, and, locally, cherty limestone. Tends to grade down through 

thin fragmented zone into underlying rock. In places matrix is sparse and only a thin lag rubble of 

relatively small fragments remains on exposed bedrock. Mapped areas include minor colluvium on 

lower slopes. Thickness 5–50 cm

LATE PLEISTOCENE

oca LACUSTRINE CLAY, SILT, AND SAND (Tahoka Formation in Texas)—Bluish-gray to gray, 

weathering light brown, selenitic lacustrine clay, silt, and locally, sand. Clay and silt are slightly 

calcareous, massive to weakly bedded, weakly coherent. Clay minerals include bentonite, sepiolite, 

and illite. Thin dolomite beds (Vigo Park dolomite, an informal, unranked unit of Reeves, 1976) in 

middle part of unit. Sand is gray, fine- to coarse-grained quartz, massive to weakly bedded, friable. 

Grades laterally into shoreline gravel at margins of deposit. Occurs on the High Plains in basins 

that developed in part by deflation, but chiefly as a result of collapse following dissolution by 

underground water of underlying salt or gypsum bedrock. Lake sediments contain late Wisconsin 

molluscs and vertebrate fossils; locally, underlain by unmapped olive-gray, dense, selenitic, 

lacustrine silt and clay of early Wisconsin age, known chiefly from borings. Thickness as much as 

25 m in places; commonly 8 m, but thins laterally to less than 1 m

LATE PLEISTOCENE TO MIDDLE PLEISTOCENE

afc ALLUVIAL- AND SHEETWASH-FAN FINE SAND AND SILT—Brown to grayish-brown, silty, fine 

sand and clayey, fine sandy silt; sand chiefly quartz. Deposited as broad, gently sloping, thin 

alluvial- and sheetwash-fan deposits. Occurs on gentle slopes of valley sides that extend upward as 

much as 60–70 m above flood plains. Largely reworked from older alluvial deposits of Seymour 

Formation (ago). Weakly to well bedded, poorly to well sorted. Locally includes minor admixed 

clay. Headwater areas may include some fragments from underlying or nearby exposures of 

Permian sandstone, siltstone, shale, gypsum, or dolomite. Thickness 1–3 m 
8

aso CEMENTED ALLUVIAL GRAVELLY SAND—Very pale brown, light-yellowish-brown, and very 

light brownish gray calcium carbonate-cemented quartz sand, silt, clay, and gravel, intermixed and 

interbedded. Includes alluvial-fan, sheetwash, and possible pediment deposits consisting of 

stratified to massive, poorly sorted clayey sand and sandy to silty clay. The sand and clay contains 

lenses of pebbles mixed with unsorted platy fragments of calcium carbonate and subangular to 

subround gravel composed of locally derived limestone, dolomite, and chert. Locally, overlies soft 

to hard, calcium carbonate-cemented gravelly loam or chalky clay. Lies topographically above 

younger terraced, weakly cemented deposits and interfingers with cemented colluvium and 

sheetwash deposits on adjacent slopes. Mapped areas include some cemented colluvium and small 

isolated areas of older alluvial deposits. Thickness commonly 2–30 m; locally, where underlain by 

Permian bedrock containing salt beds (anhydrite and halite), thickness varies abruptly and is as 

much as 80 m where deposit has filled depressions formed by collapse of the beds following 

dissolution of the salt

afb ALLUVIAL-FAN GRAVELLY TO SANDY LOAM—Pale-brown, yellow, light-yellowish-brown silty 

clay; calcareous, friable; contains interbeds of pebbly sand to sandy silt. Clasts chiefly scattered, 

rounded pebbles and cobbles of limestone, dolomite, and chert; local pebbles of basalt and 

pyroclastic rock. In places layers of concretions and sand are cemented by soft, white to very pale 

yellow calcium carbonate. Underlies, high, very gently sloping (1 percent slope) alluvial fans in 

broad valleys in central part of quadrangle. Thickness 3–12 m

LATE PLEISTOCENE TO EARLY PLEISTOCENE

asg ALLUVIAL GRAVEL, SAND, SILT, AND CLAY (alluvium of Pleistocene age, undifferentiated)—

Orange-brown or brownish-gray to brown; oxidized; upper part chiefly silt and clay; becomes 

coarser downward. Gravel is predominantly in lower part except where fine material has been

deflated. Sand is well bedded to poorly bedded; commonly crossbedded. In Texas, gravel consists 

mostly of pebbles and cobbles of calcrete, derived chiefly from the Ogallala Formation, and 

limestone. Maximum diameter about 20 cm; mostly less. Clasts of shale and platy sandstone 

present in some areas. In Oklahoma, gravel is also chiefly calcrete, but quartzite, other 

metamorphic rocks, milky quartz, chert, and fine-grained igneous rock from distant western sources 

are abundant locally. Sand is coarse to fine, well bedded to poorly bedded, commonly crossbedded, 

and chiefly quartz; feldspar abundant near Wichita Mountains. Underlies a sequence of 

successively higher terraces that have not been extensively studied and includes lag gravels remnant 

on ridge crests following erosion of Ogallala Formation. Locally, also includes Lava Creek B 

volcanic ash bed and older Pleistocene ash beds, and contains sites of several Pleistocene vertebrate 

local fauna. Thick eolian sand and silt overlie deposit in many places, especially along Red River. 

Thickness 0.2–30 m

esa EOLIAN SHEET SAND (Blackwater Draw Formation in Texas; described by Reeves (1976), formally 

defined by Holliday (1989); former "cover sands" of Frye and Leonard, 1957)—Grayish-red, 

reddish-brown, or very light brown, stratified to massive, silty to clayey, fine to medium sand. 

Commonly 1–4 laterally persistent layers, each about 1 m thick; characterized by secondary calcium 

carbonate nodules, films, and concretions, and a well-developed calcrete paleosol. More sandy in 

southwestern part of its mapped area, and more loamy in its northeastern part. Commonly contains 

thin lenticular beds of gray, organic-rich lake silt and clay, and local channels at its base are filled 

with pebbly sand. Boundary between Blackwater Draw Formation (esa) and underlying Blanco 

Formation (occ) at Mount Blanco revised by Holliday (1988). Lower part of Blackwater Draw 

Formation includes Guaje volcanic ash bed, fission-track dated as 1.4±0.2 Ma (Izett and others, 

1972). Beds from Guaje ash to base of unit have reversed magnetic polarity. Unit rests 

disconformably on calcrete at top of Blanco Formation, on Ogallala Formation, or on Cretaceous 

shale. Appears to have accumulated throughout most of Quaternary time as a series of sand sheets 

formed during brief periods of eolian deposition between longer intervals of erosion, playa lake 

deposition, and soil development. Thickness commonly 4–8 m

cab CEMENTED COLLUVIUM2 AND SHEETWASH ALLUVIUM—White, pink, light- to dark-gray, 

light-brown, yellowish-brown, and reddish-brown, and reddish-yellow sand, silt, clay, and gravel; 

extensively cemented by secondary calcium carbonate; stratified to massive; characterized by local 

concentration of secondary calcium carbonate in indurated laminar horizontal layers or as massive, 

soft zones and nodules. Forms colluvial deposits on moderate to steep slopes, and remnants of 
9

nearly level to gently sloping, discontinuous sheetwash alluvial-fan aprons that include sparse 

deposits of lacustrine clay and marl. Distribution spotty in southwest part of quadrangle. Mapped 

areas include bedrock outcrops and small deposits on uplands. Thickness typically 3–8 m; locally 

as much as 12 m

MIDDLE PLEISTOCENE AND EARLY PLEISTOCENE

ago ALLUVIAL GRAVEL AND SAND (Seymour Formation and correlative upland gravel in Texas)—

Light-gray, medium-gray, or yellowish-brown gravelly sand, silt, and clay. Locally contains zones 

of secondary calcium carbonate-cemented gravelly loam to clay. Lava Creek B volcanic ash (age 

0.61 ka) present in places. In many areas, gravel consists of rounded to subrounded pebbles and 

boulders, mostly of gray, white, black, green, and red chert and less abundant limestone and 

dolomite. Deposits from sources in Cretaceous limestone contain abundant limestone pebbles. 

Locally include a few pebbles of dark-olive siltstone, hard quartzite, volcanic rock, porphyry, milky 

quartz, banded chalcedony, and various Precambrian igneous and metamorphic rocks. Caps upland 

flats and stream divides. Thickness commonly 1-2 m, but where underlain by Permian rocks 

containing salt beds, thickness varies abruptly and is as much as 25 m where deposit has filled 

depressions formed by collapse of the beds following dissolution of the salt

ocb EOLIAN AND ALLUVIAL SAND, SILT, AND CLAY (Tule Formation in Texas)—White to gray, 

brownish-red, or reddish-gray, silty, fine to medium quartz sand, greenish-gray silt and clay, and 

thin-bedded lacustrine limestone. Sand is massive to thin bedded and contains caliche nodules; silt 

and clay are indistinctly bedded and locally bentonitic. Where bentonitic, expands when wet. 

contracts when dry. Pebbly gravel present at base of deposit. Lava Creek B volcanic ash bed (0.61 

Ma) occurs locally at top of unit. Upper(?) Cerro Toledo volcanic ash bed (age 1.23±0.02 Ma), 

downwind equivalent of the Cerro Toledo Rhyolite, occurs in lower part of map unit in canyon of 

Tule Creek. Contains molluscan and vertebrate fauna. Exposed in slopes of canyon reentrants in 

the High Plains. Thickness as much as 28 m

PLIOCENE

occ LACUSTRINE SAND, CLAY, AND LIMESTONE (Blanco Formation in Texas)—White to light-gray, 

massive to well-bedded, fine to medium quartz sand; gray to light-greenish-gray, calcareous, 

diatomaceous, silty to sandy, bentonitic clay; and white, hard, flaggy, thin-bedded, freshwater 

limestone. Sand becomes increasingly gravelly toward margin of basin. Boundary between Blanco 

Formation and overlying Blackwater Draw Formation at Mount Blanco revised by Holliday (1988). 

Contains the Mount Blanco volcanic ash bed (Izett, 1981). A possible equivalent of this ash at the 

111 Ranch fossil locality in Arizona was fission-track dated at 2.32±0.15 My by J.J. Dickson (Izett, 

1981). Entire map unit has reversed magnetic polarity (Lindsay and others, 1975) and is considered 

to represent the lower part of the Matuyama Reversed Polarity Chron (base 2.48 Ma). Mount 

Blanco volcanic ash bed overlies bone beds that contain the Blancan local fauna, the type fauna for 

the Blancan Land Mammal age. Occupies basins developed in Ogallala Formation, and is believed 

to have been deposited in a seasonal to semipermanent lake that existed between periods of 

dessication in an arid to semiarid climate. Preserved in cliffs along eastern escarpment of High 

Plains, chiefly in Blanco Canyon of the White River northeast of Lubbock. Thickness 19–24 m

QUATERNARY AND TERTIARY

zsa LIMONITIC SANDY DECOMPOSITION RESIDUUM3

—Light-gray, yellowish-brown or dark-reddishbrown, clayey to silty, fine to medium quartz sand; cemented by limonite or containing irregular 

masses, nodules, and veins of limonite. Claystone fragments locally abundant. Grades down into 

sandstone, shale, and siltstone. Mapped areas commonly include local colluvium, alluvium, and 

bedrock outcrops. Thickness 1–10 m

zsb QUARTZ SAND DECOMPOSITION RESIDUUM3

—Pale-gray to reddish-brown, and reddish-yellow, 

slightly silty to clayey, coarse to medium quartz sand, locally pebbly. Includes abundant muscovite. 

Contains irregular, hard, limonite-cemented masses and limonite nodules and veins. Grades down 

into friable to locally cemented sandstone, and, in a few places, into pebble conglomerate or 

claystone. Mapped areas include broad, low Holocene dunes derived or reworked from the 

residuum, local small areas of calcium-carbonate-cemented sandy clay residuum, thin colluvium of 

limonite-cemented rubble, and bedrock outcrops. Thickness commonly 1–3 m; locally 6–8 m
10

zsd SANDY DECOMPOSITION RESIDUUM3

—Brown to dark-grayish- or olive-brown, medium to fine 

sandy loam, very locally silty clay loam; contains angular fragments of sandstone, limestone, or 

chips of shale. Grades down through fragmented zone into underlying bedrock. Mapped areas 

include locally derived colluvium and alluvium. Mapped only in Oklahoma in northeast part of 

quadrangle. Thickness 0.5–2 m

zse CLAYEY SAND AND SANDY CLAY DECOMPOSITON RESIDUUM3

—Gray, light-brown, orange, 

or brown, clayey, fine to medium quartz sand to fine sandy silty clay; locally contains subrounded 

sandstone pebbles. Present only in southeast corner of quadrangle. Mapped areas commonly 

include some colluvium and small bedrock outcrops. Thickness 1–3 m

zsp FINE SANDY, SILTY CLAY DECOMPOSITION RESIDUUM3

—Light- to reddish-brown very fine 

sand and silty clay; gray clay; some gravel. Clasts chiefly sandstone; a few of limestone. Mapped 

areas include colluvium and bedrock outcrops. Thickness 0.5–2 m

zld CLAYEY SILT TO SILTY CLAY DECOMPOSITION RESIDUUM3

—Reddish- to dark-grayish-brown 

or dark-gray fine clayey silt to silty clay; locally calcareous. Contains small chips of shale and 

fragments of limestone and chert, or sandstone; local iron-manganese concretions. Grades down 

through fragmented zone into bedrock, mostly shale and limestone, locally minor sandstone. 

Mapped areas include bedrock outcrops on steep slopes and locally derived colluvium. Thickness 

0.25–2 m

zlq FINE SANDY LOAM DECOMPOSITION RESIDUUM3

—Reddish-brown to brown, fine sandy loam, 

locally clayey loam; slightly acid to moderately alkaline. Grades down through weathered rock into 

bedrock, mostly red, fine-grained sandstone interbedded with minor siltstone, and shale. Commonly 

thinned by slope erosion and deflation. Mapped areas include bedrock outcrops, minor alluvium, 

and local colluvium on steep slopes. Thickness less than 3 m

zlr CLAY LOAM AND FINE SANDY LOAM DECOMPOSITION RESIDUUM3

—Reddish- to dark-brown 

or brown clay loam and silty to fine sandy loam. Sand mostly quartz and feldspar. Clay loam 

grades down into soft, red shale. Silty to sandy loam grades down through weathered, fractured 

rock into red or pink, fine-grained sandstone with interbeds of siltstone. Residuum commonly 

thinned by slope erosion and deflation. Mapped areas include bedrock outcrops, minor alluvium, 

and local colluvium on steep slopes. Mapped only in Oklahoma. Thickness as much as 3 m 

zls SANDY CLAY LOAM DECOMPOSITION RESIDUUM3

—Brown to reddish-brown, fine sandy loam 

to fine sandy clay loam derived from underlying red, fine-grained sandstone, shale, and dolomite. 

Includes scattered decomposed to near-fresh rock fragments that become more numerous in lower 

part. Grades into bedrock through zone of weathered rock. Mapped areas include locally derived 

colluvium and minor local alluvium. Thickness 1–1.5 m

zlt RED CLAY LOAM DECOMPOSITION RESIDUUM3 WITH LOCAL GYPSUM RUBBLE—Reddishto dark-brown or brownish-gray clay loam, locally silt loam; grades down through zone of broken 

rock into hard shale, limestone. dolomite, or siltstone. Contact with limestone and dolomite is 

abrupt and shows evidence of solution. Sinkholes and areas of partly dissolved gypsum rubble in 

places. Mantled with thin loess. Mapped areas include minor alluvium and local colluvium on 

steep slopes. Mapped only in Oklahoma. Thickness less than 3 m over shale; less than 2 m over 

limestone

zcb SMECTITIC CLAY DECOMPOSITION RESIDUUM3

—Yellowish-gray, greenish-gray, light-gray, or 

gray clay and sand. Locally contains calcareous nodules. Clay is smectite; expands when wet; 

shrinks and cracks, forming structures called gilgai, when dry. Residuum grades down into marine 

clay, marl, calcareous sandstone, or limestone. Mapped only in Texas in southeast part of 

quadrangle. Mapped areas commonly include colluvium and small bedrock outcrops. Thickness 1–

2 m

zcc SILTY CLAY DECOMPOSITION RESIDUUM3

—Black to dark-gray or dark-brown silty clay; light to 

reddish brown where oxidized; silty clay to fine sandy clay developed from hard calcium carbonate 

or calcium carbonate impregnated sandy clay at contact with underlying bedrock. Clay is strongly 

smectitic; expands when wet, shrinks and cracks, forming structures called gilgai, when dry. 

Mapped areas include local colluvium and bedrock outcrops. Thickness 0.5–1 m, locally 2 m

zcg SAND, GRAVEL, SILT, AND CLAY DECOMPOSITION RESIDUUM3

—Dark-gray, olive-gray, or 

grayish- to reddish-brown clay loam, silt loam, fine to medium sand, or clayey sandy gravel;

contains both calcium carbonate concretions and limonite concretions. Sand chiefly quartz; gravel, 

2–10 cm in diameter, contains clasts of novaculite, quartz, quartzite, and sandstone. Clay is mostly 
11

smectite; expands when wet and shrinks when dried. Mapped areas include local alluvium, 

colluvium, and bedrock outcrops. Thickness 0.5–2 m

zcj CLAY AND SILTY CLAY DECOMPOSITION RESIDUUM3

—Grayish- to yellowish-brown or brown 

clay to silty loam, locally mottled; fine sandy loam in places; grades down into soft shale or 

fractured fine-grained sandstone or siltstone. Occurs only in Oklahoma in northeastern part of 

quadrangle. Mapped areas include bedrock outcrops, minor alluvium, and local colluvium. 

Colluvium contains as much as 15 percent sandstone and shale fragments less than 25 cm long, and 

may be as thick as 2 m on lower slopes. Thickness commonly 0.5–2 m

zcn SANDY CLAY LOAM DECOMPOSITION RESIDUUM3

—Light- to reddish-brown sandy clay loam, 

locally clay loam or silty clay loam. Includes scattered calcareous nodules and ferruginous 

concretions weathered from bedrock. Also includes some platy sandstone fragments and a few chert 

clasts. Grades down into underlying bedrock through fragmented zone. Mapped areas include 

bedrock outcrops and minor colluvium. Thickness 1–2 m

zri SILTY CLAY DECOMPOSITION RESIDUUM3 AND CHERTY CLAY SOLUTION RESIDUUM4

—

Reddish-brown or dark-grayish-brown to light-brown, silty to clayey, locally loamy, slightly acid 

residuum derived from alternating beds of shale and locally cherty limestone. Grades down through 

fragmented zone into bedrock. Decomposition residuum commonly contains shale fragments;

solution residuum, abundant chert and partly dissolved limestone fragments. On steep slopes, 

mapped areas include bedrock outcrops and locally derived colluvium. Thickness 0.5–5 m 

zrj CLAY LOAM AND CHANNERY LOAM DECOMPOSITION RESIDUUM3 AND SOLUTION 

RESIDUUM4

—Pale- to dark-grayish-brown loam, clay loam, and channery loam; locally 

calcareous. Occurs around Arbuckle Mountains in Oklahoma in central-eastern part of quadrangle. 

Solution residuum overlies limestone, contains scattered fragments of solution-surfaced limestone, 

and extends down along fractures in underlying bedrock. In places the residuum contains rounded 

limestone pebbles derived from beds of limestone conglomerate and, along northern edge of 

Arbuckle Mountains, pebbles of granite, feldspar, and vein quartz derived from an underlying 

bedrock conglomerate. Channery loam is developed from shale, contains abundant shale chips, and 

grades down abruptly into unweathered shale. Mapped areas include locally derived colluvium and 

minor alluvium. Thickness as much as 2 m on limestone, commonly 0.5–1 m on shale 

rcn CHERTY CALCAREOUS CLAY SOLUTION RESIDUUM4

—Light-reddish-brown to red clay, silty 

clay, or sandy clay developed from limestone, marl, clay, or soft sandstone. Where developed from 

limestone, contains abundant solution-rounded subangular limestone fragments and scattered chert. 

In places, secondary platy calcium carbonate present in lower 0.5 m. Contact with underlying 

limestone sharp but penetrated along fractures by residuum. Contact with underlying marl, clay, or 

soft sandstone gradational. Mapped areas include numerous bedrock exposures, chiefly limestone, 

and colluvium on steep to moderate slopes of valleys that dissect the limestone. Thickness 0.2–2 m

rcv STONY CALCAREOUS CLAY SOLUTION RESIDUUM4

—Chiefly dark-reddish-brown, pale-brown, 

to grayish-brown clay, in places enclosing areas of loamy residuum. Where underlain by limestone, 

lower part of residuum is in abrupt contact with zone of clay and remnant solution-rounded 

limestone fragments comprising 30–80 percent of the material. The fragment zone grades down into 

fractured limestone bedrock. Where underlain by shale, residuum and shale are in abrupt 

gradational contact; where underlain by chalk or marl, contact is more gradational. Mapped areas 

include bedrock outcrops and, where slopes are steep to moderate, accumulations of pale-brown, 

calcareous loamy colluvium, 1–2 m thick, that contains abundant fragments of limestone, shale, and 

secondary calcium carbonate. Thickness of residuum 1–2 m

usa FELDSPATHIC SANDY FINE GRUS5

—Pink-tan, angular fragments 2–4 mm in diameter, in clayey, 

medium to very coarse sand matrix. Fragments composed of quartz, feldspar, and biotite in 

combination or as individual crystals weathered from granite, gneiss, and schist. Mapped areas 

commonly include colluvium and local bedrock outcrops. Thickness 1–2 m

1

COLLUVIUM, for purposes of this map, is defined as material transported and deposited by masswasting processes. 2

DISINTEGRATION RESIDUUM, for purposes of this map, is defined as material derived by the 

piece-meal breaking up of rock into particles with no appreciable lateral transport. 
12

3

DECOMPOSITION RESIDUUM, for purposes of this map, is defined as material derived primarily 

by in-place chemical weathering of clastic rock with no appreciable subsequent lateral transport. 4

SOLUTION RESIDUUM, for purposes of this map, is defined as material derived by in-place 

solution of carbonate rock or carbonate-cemented rock, with no appreciable subsequent lateral transport. 5

GRUS, for purposes of this map, is defined as material derived by in-place chemical and physical 

weathering of crystalline rock with no appreciable subsequent lateral transport.

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13

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14

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Izett, G.A., and Wilcox, R.E., 1982, Map showing localities and inferred distributions of the Huckleberry 

Ridge, Mesa Falls, and Lava Creek ash beds (Pearlette family ash beds) of Pliocene and Pleistocene 

age in the Western United States and southern Canada: U.S. Geological Survey Miscellaneous 

Investigations Series Map I–1325, scale 1:4,000,000.

Izett, G.A., Wilcox, R.E.. and Borchardt, G.A., 1972, Correlation of a volcanic ash bed in Pleistocene 

deposits near Mount Blanco, Texas, with the Guaje pumice bed of the Jemez Mountains, New Mexico: 

Quaternary Research, v. 2, no. 4, p. 554–578.

Lindsay, E.H., Johnson, N.M., and Opdyke, N.D., 1975. Preliminary correlation of North American land 

mammal ages and geomagnetic chronology, in Smith, G.R., and Friedland, N.E., eds., Studies on 

Cenozoic paleontology and stratigraphy in honor of Claude W. Hibbard: Ann Arbor, University of 

Michigan Museum of Paleontology Papers on Paleontology 12, p. 111–119.

Machenberg, M.D., 1986, Stop 9—Eolian deflation and deposition, Texas Panhandle, in Gustavson, T.C.,

ed.. Geomorphology and Quaternary stratigraphy of the Rolling Plains, Texas Panhandle: Texas 

Bureau of Economic Geology Guidebook 22, p. 41–44.

Osterkamp, W.R., and Wood, W.W., 1987, Playa-lake basins on the southern High Plains of Texas and New 

Mexico—Part 1, Hydrologic, geomorphic. and geologic evidence for their development: Geological 

Society of America Bulletin, v. 99, p. 215–223. 

Plummer, F.B., 1932, Cenozoic systems in Texas, part 3, in The geology of Texas: Texas Bureau of 

Economic Geology Bulletin 3232, p. 729–795.

Reeves, C.C., Jr., 1976, Quaternary stratigraphy and geologic history of southern High Plains, Texas and 

New Mexico, in Mahaney, W.C., ed., Quaternary stratigraphy of North America: Stroudsburg, 

Pennsylvania, Dowden, Hutchinson, and Ross, p. 213–234.

Schultz, G.E., ed., 1977, Guidebook—Field conference on late Cenozoic biostratigraphy of the Texas 

Panhandle and adjacent Oklahoma, August 4–6, 1977: Canyon, Texas, West Texas State University 

Department of Geology and Anthropology Special Publication 1, 145 p.

Schultz, G.E., 1986, Stop 18—Biostratigraphy and volcanic ash deposits of the Tule Formation, Briscoe 

County, Texas, in Gustavson, T.C., ed.. Geomorphology and Quaternary stratigraphy of the Rolling 

Plains, Texas Panhandle: Texas Bureau of Economic Geology Guidebook 22, p. 82–84.
15

Seni, S.J., 1980, Sand-body geometry and depositional systems, Ogallala Formation, Texas: Texas Bureau 

of Economic Geology Report of Investigations 105, 36 p. 

Simpkins, W.W. and Gustavson, T.C., 1985, Late Pleistocene to Holocene channel aggradation, Tierra 

Blanco Creek, southern High Plains, Texas Panhandle: Geological Society of America Abstracts with 

Programs, v. 17, p. 192.

Stricklin, F.L., Jr., 1961, Degrational stream deposits of the Brazos River, central Texas: Geological 

Society of America Bulletin 72, p. 19–36.

Texas Bureau of Economic Geology, 1967, Geologic atlas of Texas, Lubbock sheet: Texas Bureau of 

Economic Geology. scale 1:250,000.

Texas Bureau of Economic Geology, 1967, Geologic atlas of Texas, Sherman sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1968, Geologic atlas of Texas, Plainview sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1969, Geologic atlas of Texas, Amarillo sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1972, Geologic atlas of Texas, Abilene sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1972, Geologic atlas of Texas, Dallas sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1974, Geologic atlas of Texas, Big Spring sheet: Texas Bureau of 

Economic Geology, scale 1:250,000.

Texas Bureau of Economic Geology, 1987, Geologic atlas of Texas, Wichita Falls-Lawton sheet: Texas 

Bureau of Economic Geology, scale 1:250,000.

Wood, W.W., and Osterkamp, W.R., 1987, Playa-lake basins on the southern High Plains of Texas and New 

Mexico—Part 2, A hydrologic model and mass-balance arguments for their development: Geological 

Society of America Bulletin, v. 99, p. 224–230. 

Unpublished and published County soil surveys by the U.S. Soil Conservation Service in cooperation with 

Texas Agricultural Experiment Station

Unpublished information and helpful comments relative to the eolian, alluvial, residual, and colluvial 

deposits of Texas were provided by T.C. Gustavson and Tucker Hentz, Texas Bureau of Economic 

Geology; Reid Ferring, University of North Texas; and V.T. Holliday, University of Wisconsin.