THE CATAHOULA SANDSTONE. 

By GEORGE CHARLTON MATSON. 

DEFINITION OF THE FORMATION. 

The name Catahoula was first used in 1905 by 

Veatch 1 as a synonym for "typical Grand 

Gulf," but the description of the formation, 

which is here quoted, was not published until 

the followingyear. 2 

Overlying the fossiliferous Vicksburg clays and limestones is a series of sandstones and greenish clays which are 

generally quite different, lithologically, from any of the 

older beds of the Tertiary series in Louisiana and Arkansas. 

The sandstones which are the characteristic feature of this 

formation range in thickness from a few inches to 50 or 60 

feet, and thicknesses of as much as 140 feet have been 

reported. 3 These sand beds are often cemented by silica 

into very hard quartzites, but such occurrences are essentially local, and the quartzitic beds pass laterally in very 

short distances into soft sandstones or even unconsolidated 

sands. These sandstones and quartzitic layers have 

resisted erosion more than the underlying clays and 

unconsolidated sands of the Eocene and so have formed 

a line of rocky hills, the Kisatchie Wold, extending across 

Louisiana, into Texas on the one hand and into Mississippi 

on the other. 

These beds contain no indication of marine life, but land 

plants are abundant and fresh-water shells have been found 

in several places. The change from the conditions existing 

in the Vicksburg is very marked and indicates an elevation 

during which the region where the oceanic conditions were 

favorable for the growth of marine life was considerably 

south of the present outcrop of the formation. 

These beds were observed at Grand Gulf, on Mississippi 

River, in Claiborne County, Miss., by Wailes, the first 

State geologist of Mississippi, who referred to them as the 

"Grand Gulf sandstones." 4 Later Hilgard 5 used the 

name ''Grand Gulf group" to include the beds exposed in 

southern Mississippi between the Vicksburg and the 

relatively recent coastal clays (Port Hudson) and the name 

1 Veatch, A. C., Report on the underground waters of northern Louisiana and southern Arkansas: Louisiana Geol. Survey Bull. 1, pt. 

2, pp. 84, 85, 90, 1905. 

2 Vmtch, A. C., Underground water resources of northern Louisiana: 

I,oui3iana Geol. Survey Bull. 4, pp. 38-40, 1906; Geology and underground water resources of northern Louisiana and southern Arkansas: 

U.S. Geol. Survey Prof. Paper 46, pp. 42-43, 1906. 

a Kennedy, William, Texas Geol. Survey Third Ann. Rept., p.63, 1892. 

4 Wailes, B. C. I,., Agriculture and geology of Mississippi, pp. 216-219, 

1857. 

5 Rilgard, E. W., Report on agriculture and geology of Mississippi, pp. 

147-154, 1860. 

has been used with varying shades of meaning by different 

authors since that time. 6 

In view of this confusion and in order to furnish a name 

not likely to be misunderstood, the name Catahoula formation is used in this paper as a synonym for the "typical 

Grand Gulf" or the ''Grand Gulf proper.'' This new 

name is from Catahoula Parish, La., 7 which is directly 

across the Mississippi Valley from Grand Gulf and where 

there are many outcrops which are lithologically and 

stratigraphically counterparts of the beds of the old type 

locality. 

Investigations made by the author in 1911 

showed that the beds at the Catahoula type 

locality are in part the equivalent of the Chattahoochee formation and in part the equivalent 

of the Vicksburg limestone, and that although 

Veatch defined the Catahoula as of Oligocene 

age, he included in his maps and descriptions of 

the formation sandstone and quartzite of 

marine origin that are now known to belong to 

the Fayette sandstone, of Eocene age. It is 

proposed to restrict the name Catahoula to the 

nonmarine deposits (of Oligocene age) found 

at the type locality and to eliminate the marine 

Eocene sandstones and quartzitic beds with 

associated clays of the Kisatchie Wold, included by Veatch in his description and mapping of the formation. These sandstones and 

quartzites contain imprints of marine fossils, 

and some of .the associated clays are darker and 

more calcareous than those of the typical 

Catahoula. From their relations to the typical 

Jackson deposits these beds are known to be of 

Jackson age, and they are also known to repre6 In this connection see the following: Smith, E. A., and Aldrich, T. H .. 

Science, new ser., voL 16, 1902, pp. 835--837; Idem, vol. 18, 1903, pp. 2()..26; 

Dall, W. H ., Science, new ser., vol. 16, 1902, pp. 946-947; Idem, vol. 18, 

1903, pp. 83-85; Hilgard, E. W., Science, new ser., vol. 18, 1903, pp. 

18()..182. 

1 It may be of historic interest to note that one of the first references 

to the outcrops of this formation is to the exposures at Cataboula Shoals 

in Catahoula Parish, which were even at that early day correctly correlated with the exposures east of the Mississippi. (See Darby, William, 

A geological description of the State of Louisiana, pp. 45-46, Philadelphia, 1816.) 

209 
210 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

sent the eastward extension of the Fayette other portions of Louisiana and Texas, so that 

sandstone. office work was not completed until the summer 

The name Catahoula formation as originally of 1914. · 

used by Veatch was intended as a synonym for PREVIOUS INVESTIGATIONS. 

"typical Grand Gulf" or the "Grand Gulf 

proper." The present usage makes it include 

that portion of the "Grand Gulf" which is 

equivalent to the Chattahoochee formation and 

the Vicks burg limestone in the western part 

of the Gulf embayment. It is believed that 

subsequent study may permit the separation of 

the formation into two parts, one equivalent to 

the Chattahoochee formation and the other 

equivalent to the Vicksburg limestone. 

The validity of Veatch's objection to the old 

name "Grand Gulf" is strengthened by the 

recognition of beds of Vicksburg age at the type 

locality of the Catahoula sandstone-Catahoula Parish, La. An additional reason for 

abandoning the name "Grand Gulf" is that it 

originally included nearly all the Tertiary 

deposits younger than the Vicksburg limestone. 

ORIGIN OF TIDS INVESTIGATION. 

During the spring of 1910 the writer, working under the direction ofT. Wayland Vaughan, 

began a study of the younger Tertiary beds of 

the Gulf Coastal Plain. This investigation 

was intended to cover the Tertiary formations 

younger than the Vicksburg limestone, and, as 

originally planned, the field studies were to 

begin in western Florida and were to be extended as rapidly as practicable across Alabama and Mississippi, with a hasty reconnaissance on the west side of Mississippi .River 

for the purpose of correlating the formations 

east of the river with the formations recognized by Veatch 1 in Louisiana. 

As the work progr:essed it became apparent 

that the investigations serving as a basis for 

the conclusions reached by Veatch were not 

sufficiently thorough to permit satisfactory 

correlation, and the plans were enlarged to 

include a portion of the State of Louisiana. 

The field investigations were interrupted by 

many demands for work in other areas and 

were not completed until May, 1913. The 

preparation of the reports was still further 

delayed by the demands for investigations in 

1 Veatch, A. C., Geology and underground water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 

pp. 42 et seq., 1906. 

The first report mentioning the "Grand Gulf 

sandstone" is that by Wailes, of the Mississippi 

State Geologica] Survey.2 This author described the typical materials found at Grand 

Gulf, on Mississippi River, and correlated 

them with what he called the Davion rock, at 

the place now known as Fort Adams, farther 

down the river. He succeeded in tracing 

sandstone eastward from Grand Gulf throughout the area between the Bayou Pierre and Big 

Black River, and eastward to the vicinity of 

Raymond and Mississippi Springs, though he 

noted the fact that the rock changes in 

character, becoming more uniform in texture 

and softer east of Grand Gulf. His description 

of the equivalent of the "Grand Gulf sandstone" in the vicinity of Bayou Pierre and 

Mississippi Springs was apparently the r~ult 

of field observations, and he drew a correct 

conclusion concerning the continuation of this 

formation eastward beyond Pearl River. 

The next extensive report dealing with the 

"Grand Gulf'' was published in 1860 by Hilgard/ then State geologist of Mississippi. 

This publication gave a more comprehensive 

description of the "Grand Gulf sandstone," 

which, as in Wailes's report, was made to 

include the rock as far south as Fort Adams. 

Several excellent sections were described in· 

detail, and the information about specific 

lo~alities was unusually full. The report was 

evidently the result of extensive field investigations covering the entire area from Mississippi 

River to the eastern boundary of the State. 

Hilgard wished to determine the economic 

value of this as well as other geologic formations, and he therefore gave a large amount of 

time to the study of the lithology and chemical 

composition of the rocks included in the "Grand 

Gulf." He mentioned the absence of marine 

fossils in this formation, the general lack of 

calcareous materials, the wide distribution of 

gypsum and salt, and the presence at certain 

2 Wailes, B. L. c., Report on the agriculture and geology of Mississippi, pp. 216-219, 1854. . . 

a Hilgard, E. W., Report on the geology and agriculture of Mississippi: 

pp. 147-154, 1860. 
THE CATAHOULA SANDSTONE. 211 

localities of fossil wood and leaves. His conclusions concerning the nonmarine character 

of the formation appear to be in the main correct, as is also the table showing the "Grand 

Gulf formation," as he mapped and described 

it, containing representatives of geologic formations ranging in age frmn the top of the 

Oligocene Vicksburg limestone to the Pliocene. 

In the description of different localities Hilgard's report is an exceptionally valuable 

source of information to those who wish to examine the different types of sediments included by him in the formation. 

After the appearance of Hilgard's report 

many years elapsed before field investigations 

were again undertaken in the areas where the 

"Grand Gulf formation" is exposed. In 1893 

Johnson 1 described the extension of the 

"Grand Gulf" into Alabama and divided it 

into four phases, which, arranged in order from 

the oldest to the youngest, are (I) the Bayou 

Pierre phase, in which the rock is highly siliceous and in places quartzitic; (2) the Fort 

Adams or Ellisville phase, including the softer 

sandstones and dense clay; (3) the Hattiesburg 

phase, which is less siliceous than the two preceding and in places lignitic; (4) the Pascagoula 

phase, which consists of tenacious clays containing calcareous nodules and locally abounding in shells of mollusks. Unfortunately, some 

of the lines separating the different phases are 

apparently drawn diagonally across the strike 

and they do not separate distinct lithologic or 

time units. The first two phases of the "Grand 

Gulf," as discussed by Johnson, appear to include the -Catahoula sandstone and in some 

places younger beds. 

A report by E. A. Smith,2 published in 1894, 

was confined largely to a discussion of the 

"Grand Gulf" and other formations in the 

State of Alabama, but reference was made to 

the classic localities of Hilgard and Wailes in 

Mississippi. Most of the beds in Alabama that 

Smith classed as "Grand Gulf" are now correlated with the formations belonging to the 

Apalachicola group as developed In eastern 

Alabama and western Florida. 

A subsequent paper by Smith and Aldrich 3 

described the "Grand Gulf" of southern Alabama and assigned to it a position in the 

geologic column above the Pascagoula phase 

of Johnson. In this discussion the "Grand 

Gulf" was made to include the mottled clays, 

sands, and sandstones resting upon the Vicksburg limestone and other clays and sands of 

similar appearance lying stratigraphically above 

some of the younger Tertiary formations. The 

''Grand Gulf," according to these authors, 

would therefore be a blanket formation of relatively recent geologic age, or, as th:e authors 

describe it: 

· Our recent observations, however, of the unconformity 

existing between the Grand Gulf and the fossiliferous 

Tertiary beds in these localities, and of the occurrence of 

the former as surface beds southward to the very shores 

of the Gulf, compel us to change out views and to assign 

to the Grand Gulf a place in the stratigraphic column not 

only far above the Tertiaries exposed on the Chattahoochee 

and Escambia rivers, but also above any unquestioned 

Tertiary existing in Alabama. 

The evidence of the comparatively recent age of the 

Grand Gulf formation thus furnished by its surface distribution is confirmed and extended by the materials brought 

up from three deep wells bored in Mobile County, viz, 

one at the brewery in the city, one about 3 miles south- · 

west of the city (the Bascom well), and one at Alabama 

Port on Mon Louis Island, near the southeastern end of 

the county. 

From the foregoing quotation and the list of 

fossils given by these authors it is clear that 

they regarded the ''Grand Gulf'' -as younger 

than the Pascagoula. 

In discussing the paper by Smith and Aldrich, Dall 4 expressed the opinion that the beds 

they described comprised only the upper portion of what Hilgard called "Grand Gulf." In 

the same paper Dall restated his views concerning the tentative use of the term "Grand · 

Gulf," as follows: 

In 1898 5 I was obliged to decide on some portion of the 

original Grand Gulf which should continue to bear the 

name, after deduction of beds of which the age had been 

determined, and fixed upon the Oligocene clays containing 

lignite and. fossil palm leaves, the only fossils cited by 

Hilgard in his original description, and in my table of 

Tertiary horizons referred to them as "typical Grand 

Gulf." The beds which Messrs. Smith and Aldrich call 

I Johnson, L. C., The Miocene group of Alabama: Science, vol. 21, pp. a Smith, E. A., and Aldrich, T. H., The Grand Gulf formation: Science, 

9~91, 1893. new ser., vol. 16, pp. 83&-837, 1902. 

'Smith, E. A., Johnson, L. C., and Langdon, D. W., Report on the 4 Dall, W. H ., The Grand Gulf formation: Science, new ser., vol. 16, 

geology of the Coastal Plain of Alabama, pp. 97-107, Alabama Geol. pp. 946-947, 1902. 

Survey, 1894. 6 U.S. Geol. Survey Eighteenth Ann. Rept., pt. 2, p. 340 and table. 
212 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

"Grand Gulf" in their communication to Science are not 

the same but are the nonfossiliferous upper portion at the 

other end of Hilgard's Grand Gulf section. I have little 

doubt that their assumption as to tho late, possibly Pliocene age of these beds is correct, though it can only be 

proved by further and paleontological evidence, but this 

_decision is merely an equivalent of the ideas above cited 

from Hilgard and therefore not new. 

The views held by Smith and Aldrich were 

elaborated in a later paper 1 which sums up 

their conclusions: 

1. The Grand Gulf of "Messrs. Smith and Aldrich" is 

the same fossiliferous formation which Hilgard has described by that name, and not merely "the upper nonfossiliferous portion at the other end of Hilgard's section." 

It is the same formation which Professor Dall calls the 

"typical Grand Gulf" in his recent communication and 

which he considers Oligocene, and a remnant of the heterogeneous Grand Gulf of Hilgard. We are compelled by the 

facts to believe that this typical Grand Gulf is not Oligocene 

at all, but that it belongs about a quarter of a mile vertically above the place in the geological scale to which it is 

assigned by Professor Dall. 

2. There is also no Miocene Grand Gulf, as Langdon's 

discovery has proved and as has been confirmed by 

other geologists who have studied the ChattahoocheeApalachicola section. We might perhaps more correctly 

say there is no Miocene Grand Gulf below the horizon of 

the Pascagoula, if that be certainly proved to be Miocene. 

3. We think our facts prove that the Grand Gulf, all 

and singular, . occupies a place in the geological column 

below the Lafayette and above the Pascagoula (which is the 

uppermost of the Tertiary formations as. yet determined 

along the Gulf coast). This is all we have endeavored to 

show, and it was the raison d'E!tre of our first note. We do 

not see wherein what we have there said in any way 

confirms Professor Dall 's ' ' earlier determinations'' and, 

furthermore, we think that our view of the age of the 

Grand Gulf is new, and not a mere equivalent ofthe views 

of any other geologist. 

In a paper by Dall 2 published subsequently 

he restated his opinion that the "Grand Gulf" 

as a whole does not lie stratigraphically above 

the Pascagoula clay. After disclaiming 

knowledge based on personal observation, he 

cited, in support of his position, the statements 

of Wailes, Hilgard, Smith, Harris, and Miss 

Maury. The statement by Miss Maury 3 is 

given below. 

The Grand Gulf sandstones reach their eastern limit in 

south-central Alabama. Near Oak Grove the typical 

I Smith, E. A., and Aldrich, T. H., The Grand Gulfformation: Science, 

new ser., vol. 18, pp. 20-26, 1903. 

2 Dall, W. H., The Grand Gulf formation: Science, new ser., vol. 18, 

pp. 83-85, 1903. . 

BMaury, C. J., Comparison of the Oligocene of western Europe and the 

southern United States: Bull. Am. Paleontology, vol. 3, No. 15, p. 70, 

1902. 

sandstone beds pass beneath the Oak Grove sand, indicating that the sandstone is approximateJy of the same 

age as the Chattahoochee. 

Dall 4 divided the "Grand Gulf" into "typical Grand Gulf," the equivalent of the lower 

part of the Chattahoochee; Ellisville phase, 

Grand Gulf ( n, represented in the upper part 

of the Chattahoochee; beds in Alabama and 

Georgia corresponding to the Chipola marl of 

the Apalachicola section; and the Hattiesburg 

phase and Oak Grove sand, equivalent to the 

Alum Bluff. He separated the Pascagoula 

from the "Grand Gulf," and his subdivisions 

were the same as those made by Johnson.5 

In 1896 Vaughan 6 discussed the "Grand 

Gulf group" in Louisiana, and, following the 

classification adopted by Dall, assigned it to 

the upper Oligocene: 

The upper Oligocene of Louisiana is represented by the 

Grand Gulf group of Hilgard. These rocks have been 

described by Hilgard, Hopkins, Johnson, and Lerch. 

They are composed of clays, sands, claystones, sandstones, 

and quartzites. So far no fossils, except a few plants, 7 

have beeri collected and determined from them, but they 

are referred to the Upper Oligocene because they are 

without doubt the same as the Grand Gulf of Mississippi, 

the age of which has been fixed. 8 

The literature contains many other references 

to this formation, but inasmuch as the classifications adopted agree with one or another of 

those already mentioned, it does not appear 

necessary to cite all these references. 

The first definition of the Catahoula is found 

in two reports by Veatch,9 who described the 

materials occurring west of Mississippi River, 

correlated them with the typical "Grand Gulf 

sandstone" at Grand Gulf, Miss., and introduced the new name because of the confusion 

concerning the use of the name ''Grand Gulf'' 

by some of the earlier investigators. 

4 Dall, W. H., and Stanley-Brown, Joseph, Cenowic geology along 

the Apalachicola River: Geol. Soc. America Bull., vol. 5; p. 170, 1894. 

5 Johnson, L. C., The Miocene group of Alabama: Science, vol. 21, pp. 

90-91, 1893. 

a vaughan, T. W., A brief contribution to the geology and paleontology of northwestern Louisiana: U. S. Geol. Survey .Bull. 142, p. 24, 

1896. 

7 Knowlton, F. H., U. S. Nat. Mus. Proc., vol. 11, pp. 89-91, 1888. 

s Dall, VV'. H., and Stanley-Brown, Joseph, Geol. Soc. America Bull., 

vol. 5, pp. 164, 167,1894. Smith, E. A., Am. Jour. Sci., 3d ser. , vol. 47, 

p. 296, April, 1894; Chart to geological map of Alabama, 1894. Dall, 

w. H .,_ U. S. Geol. Survey Eighteenth Ann. Rept., pt. 2, 1898. 

9 Veatch, A . . C., Underground waters of northern Louisiana and 

southern Arkansas: Louisiana Geol. Survey Bull. 1, pp. 84, 85, 90, 1905; 

Geology and underground water resources of northern Louisiana and 

southern Arkansas: U. S. Geol. Survey Prof. Paper 46, pp. 42- 43, 1906. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XLVIII 

A. INTERLAMINATED AND INTERBEDDED SANDSTONES AND CLAYS. 

B. SANDSTONE CONTAINING IRREGULAR MASSES OF CLAY. 

LITHOLOGIC CHARACTER OF THE CATAHOULA SANDSTONE. 

Photographs by E. W. Shaw. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XL!X 

.A. FINE-GRAINED SANDSTONE 3 MILES NORTHEAST OF FLORENCE, MISS. 

B. WEATHERED SANDSTONE GRADING TO RED SAND, NORTHEAST OF FLORENCE, MISS. 

LITHOLOGIC CHARACTER OF THE CATAHOULA SANDSTONE. 

Photographs by E. W. Shaw. 
THE CATAHOULA SANDSTONE. 213 

Vaughan 1 presented in a recent correlation 

paper the following quotation from a manuscript by Alexander Deussen: 

As here interpreted, the Catahoula sandstone is a lithologic and stratigraphic unit which transgresses several 

biologic zones. Stated differently, it is conceived to be 

of different ages and to have been laid down at different 

periods in the different regions of its occurrence. In 

southwest Texas it is of Claiborne age, and this . kind of 

deposition seems to have begun in this area as early as 

Claiborne time. In central Texas, in the region of the 

Brazos, it is largely of Jackson age. In eastern Texas it 

is largely of Vicksburg age. According to Matson, the 

vertical transgression continues across Louisiana into 

Mississippi, where the formation is of post-Vicksburg age. 

This kind of deposition began in southwest Texas in 

Claiborne time, gradually shifted eastward, and prevailed 

in Mississippi as late as middle Oligocene time. If this 

interpretation is correct it precludes the possibility of an 

unconformity between deposits of Eocene and Oligocene 

ages in the Coastal Plain; no evidence of such unconformity has been found. 

LITHOLOGY. 

UNWEATHERED MATERIALS. 

The Catahoula sandstone is composed of 

many alternations of sandstones, sands, and 

clays, the arenaceous sediments predominating 

and the argillaceous materials being distributed 

in more or less extensive beds of lenticular 

shape. (See Pis. XL VIII and XLIX, A.) 

Loose sands are comparatively rare, and interlamination of sands and clays is not conspicuous. The sandstones are commonly fine 

grained, and many of them contain more or 

less clay. Locally coarse-grained sandstones or 

fine-grained · conglomerates are found, and the 

material is largely quartz, either in the form of 

pebbles or sand. · In some of the sand the particles are so minute that the rock resembles 

clay. An exception to the general character 

of the conglomerate is found in layers of clay 

pebbles that have been noted in the sandstones 

and in the sands resulting from weathering. 

These clay pebbles and those formed from 

quartz are commonly distributed in lines parallel to the stratification of the rock, though they 

are in few places so numerous as to make a 

definite stratum themselves. In some places 

masses of clay a few inches in diameter occur in 

association with pebbles. The occurrence of 

clay conglomerates is not restricted to any portion of the formation, but the pebbles are scattered from top to bottom and appear to be the 

result of local conditions of sedimentation 

rather than to indicate any widespread unconformity. 

Cross-bedding is general throughout the formation (see fig. 21 and Pl. LIII, A, p. 220), 

and in some places short lenses of sandstone 

show concentric banding. The beds are as a 

rule only slightly indurated (see Pl. LIII, B), 

though in a few places in western Mississippi 

the rock is sufficiently well cemented to be used 

for building stone. At Grand Gulf, Miss., near 

Pollock, La., and at some other localities thin 

layers are firmly cemented into a very dense 

quartzite, but rock of this type is apparently of 

only local occurrence. A change from slightly 

consolidated sands to quartzite in this formation would scarcely be expected, but it has 

occurred in some places where the type and 

quantity of mineral matter in solution in th~ 

waters furnished favorable conditions for the 

deposition of silica in the sands. 

The sandstones and sands vary in color from 

gray to white, with locally a light-greenish 

tinge. The clays are commonly massive, more 

rarely interlaminated with sand, and show n. 

tendency toward cuboidal fracture. Many of 

the clay beds are shown by an ordinary hand 

lens to contain a very large percentage of fine 

sand, and in some places this material is noticeable without a lens. In general the clays are 

somewhat sandy, though some thin beds are 

notably free from silica. Selenite and probably 

some of the amorphous forms of gypsum are in 

places abundant in the clays and occur in a few 

localities in the sandstones. Here and there 

rosettes of calcium carbonate occur on the surfaces of the clay layers and in the crevices where 

the clays are slightly broken or jointed. These 

rosettes have usually been regarded as accumulations of gypsum, but many of them dissolve 

with vigorous effervescence when placed in 

dilute hydrochloric acid, revealing the presence 

of the carbonate. 

The clays of the Catahoula sandstone have a 

wide range in color, from light gray or white to 

brown or black. The dark colors are due to 

the presence of organic matter, either in thin 

lamirire or distribut.ed in the form of particles J Index to the stratigraphy of North America: U. S. Goo!. Survey 

Prof. Paper n, p. 790,1912. . of lignitized wood. The purer clays are pale 
214 SHORTER. CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Leesville Light & 

Waterworks Co., Limited 

Leesville, Vernon Parish, La. 

Hattiesburg 

clay 

Catahoula 

sandstone 

Fayette 

'sandstone 

Older 

Eocene 

Elevation 235' 

DE;pth In 

feet 

Sand and clayWhite clay and sand 

Lignite - Gumbo 

Water sand 

Packed sa11d and shale Sand 

Packed sand 

Fine white sand Hard shale ... Sand,"salt and pepper; medium Gumbo 

Sand and shale Gumbo, tough 

Gumbo 

~g~.;:m:@:!@;m ~~~\o 

Sand and shale 

m.:j::~§~ ~~~~"salt and peppet'; water 

Pleistocene 

and Recent · 

Hattiesburg clay 

Catahoula 

sandstone 

Fayette 

~anastone 

Pineville, 

Rapides Parish, La. 

Elevation 120'? 

Depth in feet 

20 

22 

32 

50 

90 

122 - 179 

Z29 

3Z4 

3ZS 

4ZS 

460 

536 

608 

650 

77.0 

800 

805 

9Z3 

927 

Light?.'~~on'Yt~~~~ f'~n;, I ittre 

Light-f!ray sand,7ine,yellow slreaks, clayey , No sample Light-gray sandy clay 

Clay with some thin beds of sand (No sample) 

Sandstone 

Clay 

Greenish clay mixed with fine sand 

No sample 

Granular' gray clay, calcereous 

No sample 

Light-gray fine sand, argillaceous 

Light-gray fine sand. some black grains · 

l.ight-gra,y sand, very fine, m1caceous 

~~~t~~aXsc~6o~f~ 1~~~~~adf:~~tC::'~ Mixed ·light and dark gray calcareo-us, clay, some sand 

Gray calcareous clay, fine sand 

FIGURE 18.-Diagrammatic sectbns of the Catahoula sandstone, from logs and samples of cuttings of wells at Pineville and Leesville, La. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE L 

TOPOGRAPHIC MAP 0~.., A PORTION OF THE FLORENCE QUADRANGLE, MISSISSIPPI 

Showing the characteristic rugged topography of the Catahoula sandstone areas. 

the level plain developed on the underlying Vicksburg limestone, 

~ 

and the broad valley of Pearl River 

S ca1e _ _l,_ 

62,500 

l 2 0 l 

---.=-.=-~=====-======r===--.. - - 1 l 2 0 l 2 3 4 EI:::C3::E3::.ECE!::-'=.t==-=- ~ =--=---=~----~--

Contour interval 2 0 f e et. 

4 }.file s __ .::J 

5 Ki.l()ID.ete;rs 3 
THE CATAHOULA SANDSTONE. 215 

blue or green when first exposed to the at~ 

mosphere, but on weathering the color changes 

to gray or white. 

The thicknesses of the different beds in the 

formation are indicated in a general way by 

the sections in figure 18. 

WEATHERED MATERIALS. 

V\'hen exposed to the weather the sandstones 

of the Catahoula change from light gray or 

white to deep red or yellow, the transition 

commonly being effected through various 

stages of mottling. The change in color is in 

places due to the presence of grains or small 

nodules of iron sulphide in the form of pyrite, 

or marcasite, which on exposure to the moisture and oxygen of the air changes to the 

hydrous oxide of iron. In this process the 

chemical compounds which are produced exercise a disintegrating effect upon the sandstone, tending to break it down into more or 

less incoherent sand. During the first stages 

the sandstones exhibit a spotted and blotched 

appearance at points where the iron compounds 

were originally most abundant, and .as the 

weathering progresses the color becomes a more 

nearly uniform red and thereafter changes 

gradually to orange or pale yellow. (See Pl. 

XLIX, B.) In examining beds of this sandstone it is in places possible to trace every 

gradation from the original light-colored rock 

to the final product of mature weathering, 

orange-colored and yellow sand. Certain peculiarities of the texture of the rock are not 

affected by weathering; for example, where 

there were layers of pebbles in the original 

sandstone the pebbles are arranged in a similar 

way in the weathered sand. 

The weathering of the clays produces a 

more or less sandy, plastic _mass of orange or 

yellow color, but they pass through the same 

stages of mottling and blotching as the sandstones. During the early stages of the process 

a peculiar purplish-red color is produced, 

though this color is not characteristic of this 

particular terrane but is found also in other 

formations, both older and younger. 

PALEONTOLOGY. 

Fossils are rare in the Catahoula sandstone, 

no remains of marine invertebrates having yet 

been specifically identified and only a few 

localities showing any trace of organic life other 

than lignitized wood. Fossil shells of the genus 

Unio have been noted in a few places, among 

them being areas of sandstone in the chalk 

hills in Louisiana, and imprints of oyster shells 

were found in a lens of limestone a mile east of 

Lena, La. At a few places imprints of leaves 

sufficiently well preserved to be identified have 

been collected, and these are described on 

pages 227-243 by E. W. Berry. Silicified wood 

is widely distributed throughout the formation, 

and the most common fragments are those of 

palm trees. 

TOPOGRAPHY. 

The area in which the Catahoula sandstone 

is exposed has been extensively eroded, the 

surface being reduced to slopes. The major 

streams have cut broad, steep-sided valleys 

across this formation, and their tributaries 

have extended their ramifications so as to 

drain the entire area. The principal rivers 

crossing the formation are Sabine River, on 

the western boundary of Louisiana, and the 

Mississippi and its tributaries, including Red 

River in Louisiana and Big Black, Pearl, and 

Chickasawhay rivers in Mississippi. In the 

region covered by the Catahoula sandstone 

there is a difference in elevation of 100 to 

nearly 300 feet between the levels of the 

streams and the heights of the neighboring 

portions of the upland. The accompanying 

topographio map of a portion of the Florence 

quadrangle, Miss. (Pl. L), shows the characteristic hilly topography of the Catahoula sandstone, the comparatively level plain developed 

on the Vicksburg limestone, and the broad 

valley of Pearl River, one of the principal 

streams in Mississippi. 

The major streams have meandered enough 

to develop broad, steep-sided valleys across 

the Catahoula sandstone, and most of the valleys have been excavated below their present 

levels and then partly refilled with aliuvium. 

The amount of this filling is in most places 

great enough to conceal the underlying Catahoula except on the convex curves of some of 

the meanders. Pearl River presents unusual 

conditions because it is partly obstructed at 

several places by hard layers of sandstone or 

clay that produce stretches of quiet water 

interspersed with rapids. Similar conditions 

are found on Red River near Alexandria, 
216 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY 1 1916. 

though the conditions there are explained by 

the fact that the river has been deflected from 

its old channel in recent geologic time, and a 

new channel has been formed across spurs of 

the Catahoula sandstone that project from the 

adjacent hills. 

The northern margin of the formation is 

characterized by hills ri$ing more or less 

abruptly above the older geologic formations. 

(See fig. 19.) The name Kisatchie Wold was 

used by Veatch 1 to designate the line of high 

hills in Louisiana south of the contact between 

the Catahoula formation, as he used the name, 

and the Jackson formation. Although this 

portion of the Catahoula of Veatch is now 

correlated with the Eocene Fayette sandstone, 

the wold is sufficiently typical of scarps procemented into irregular ledges of quartzite. 

Sands are usually more resistant than clays 

because they are less easily attacked by rain 

water and sheet erosion and are less readily 

affected by small streams such as those which 

do the major part of the erosive work over the 

large areas underlain by the formation. The 

sand beds therefore cap hills where they overlie formations that consist of clays and marls. 

One of the principal reasons for the greater 

resisting power of porous materials, such as 

sand, is that water sinks readily into the pores 

between the grains and the amount of surface 

wash is thereby greatly lessened. Water enters 

marls and clays with much greater difficulty, 

but after having gained access to the upper 

layers it imprisons the air contained in the 

FIGURE 19.-Fayette sandstone forming northward-facing scarp of the Kisatchie Wold 

north of Hornbeck, La. 

duced under similar conditions to warrant 

description. (See Pl. LI, ..A..) This topographic feature owes its existence to the . fact 

that the sands and sandstones of the Fayette 

are more resistant than the clays and marls of 

the Jackson formation, to the north, and consequently the softer beds have been reduced 

to lower levels, while the sands and sandstones 

remain as ridges and hills, with steep slopes to 

the north and gentle, dip slopes to the south. 

The greater resistance of the Fayette sandstone is not altogether due to the fact that 

its beds are hard, because, even though they 

contain many hard layers, the sands and sandstones as a whole are friable except where they 

have been either ·case-hardened by the deposition of cementing material on the surface or 

1 Veatch, A. C., Ge::~logy and underground water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 

p .. 15, 1906. 

pores below It and, by exerting pressure upon 

this confined air; causes the separation of the 

particles and facilitates their removal by 

erosion. It is therefore apparent that even 

where a formation is composed of incoherent 

sand it may be expected to resist erosion more 

than clays or marlS. 

The Kisatchie Wold is less prominent east 

~f the Kisatchie Hills in western Louisiana, 

but in eastern Louisiana · the northern margin 

of the Catahoula sandstone forms a high ridge 

above the area to the north. The superior 

resistance of the sand beds causes more or less 

marked constrictions in the valleys where the 

rivers cross the formation. This is especially 

noticeable in the valley of Mississippi River, 

but the effect is accentuated because the 

Mississippi Valley just above the outcrop of 

the Catahoula sandstone is a composite of the 

valleys of the main stream and some large 
U.S. GEOLOGICAL SURVEY 

A. LITHOLOGIC CHARACTER OF THE JACKSON 

FORMATION. 

Showing the interbedded dark clay and lenticular layers of the Fayette sandstone which form the gentle slope 

in the foreground of figure 19. 

PROFESSIONAL PAPER 98 PLATE L1 

u 

:FJ 

B. TOPOGRAPHIC ASPECT OF THE CATAHOULA 

SANDSTONE. 

Showing sands and clays 3 miles southwest of Waynes- boro, Miss. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE Lll 

L R 

LITHOLOGIC CHARACTER OF THE CATAHOULA SANDSTONE EXPOSED IN THE BLUFF SHOWN IN PLATE LI, B. 
THE CATAHOULA SANDSTONE. 217 

tributaries. However, the presence of the 

resistant sands and sandstones of this formation no doubt helped to control the points of 

junction of the main stream and tributaries 

by deflecting the tributaries. East of the 

Mississippi the Catahoula sandstone is less 

prominent topographically than in Louisiana, 

though it continues to form a noticeable scarp 

facing toward the north. 

Rugged topography is found wherever the 

sands and sandstones of the Catahoula formation are deeply eroded, and steep slopes are 

produced by layers of indurated sandstones 

that cap hills. In many places the surface has 

been almost entirely reduced to slopes and the 

divides form long, winding ridges, but steep 

bluffs ;may be found on some of the major 

streams. (See Pl. LI, B.) The valleys of 

the small streams are distinctly V -shaped and 

the drainage has a dendritic form. 

Along the northern n1argin of the Catahoula 

sandstone the streams show a tendency to follow the outcrop of the softer formations that 

underlie the Catahoula, but few well-defined 

examples of consequent drainage were noted, 

other than some of the small streams. One of 

the best· examples of consequent drainage along 

the northward-facing scarp is Bayou Toro, a 

tributary of Sabine River in western Louisiana. Bayou Toro follows the north edge of 

the Kisatchie Wold for several ;miles and receives a number of tributaries from the scarp. 

These tributaries belong to the class known as 

obsequent streams and are similar to those 

that have developed along the landward margin of the Catahoula sandstone at many other 

places. 

STRUCTURE. 

could be devoted to this problem during the 

writer's general reconnaissance. 

The absence of saline domes on the outcrop 

of the Catahoula is noteworthy when it is considered that such structures occur in Louisiana 

in the area north of the Catahoula sandstone, 

where Eocene beds are exposed, and also in 

the area to the south, where the Pleistocene 

and younger Tertiary formations overlie the 

Ca tahoula. Where the Ca tahoula is at the 

surface the absence of domes is explained by 

the porous and resistant character of the beds. 

It may be arg~ed that the lithologic character 

of the formation does not furnish a satisfactory 

explanation of their absence, because the 

domes near the coast pass through the sandstones, but this argument is believed to be 

invalid. The formation was laid down near 

the strand line and it becomes much thinner 

and more argillaceous toward the Gulf; consequently it is represented in the belt of coastal 

domes by a thin deposit that should be less 

resistant to doming than the sandstones at 

the outcrop. 

DIP OF THE CATAHOULA SANDSTONE. 

GENERAL DIRECTION. 

Local observations on the dip of the Catahoula sandstone show that there is in many 

places an inclination in a general southerly 

direction. The prevalence of these local dips 

indicates that the formation is not horizontal, 

as has been stated by Hilgard.1 

At their lines of contact the Vicksburg and Grand Gulf 

rocks consist almost throughout of lignite-gypseous laminated clays, passing upward into more sandy materials. 

They are not sensibly unconformable i.n place; but while 

the Vicksburg rocks show at all long exposures a distinct . ABSENCE OF DEFORMATION AND SALINE southward dip of some s o t o 5o' the positions of the Grand 

DOMES. Gulf strata can rarely be shown to be otherwise than nearly 

The Catahoula sandstone has undergone or quite horizontal on the average; although in many cases 

faults or subsidence have ·caused them to dip, sometimes little deformation and presents no marked. quite steeply, in almost any direction. structural features. From the attitude of the 

sandstones gentle folds of small extent may be It is true that in places the sandstone dips 

inferred at many places, but it is not every- in other directions, but the preponderance of 

where easy to distinguish between cross- southerly dips is noticeable in any long series 

bedding on an extensive scale and inclination . of exposures like that on Pearl River. 

of beds. Because of the absence of ex ten- Smith and Aldrich 2 considered the Catahoula 

sive exposures, the confusion occasioned by . to be a blanket formation of comparatively 

the lenticular character of the layers, and the 

extent of cross-bedding, it will require a greater 

length of time to decipher the structure than 

1 Hilgard, E . w., The later Tertiary of the Gulf of Mexico: Am. Jour. 

Sci., 3d ser., vol. 22, p. 58, 1881. 

2 Smith, E. A., and Aldrich, T . H., The Grand Gulf formation : Science, 

new ser., vol. 16, No. 142, pp. 835-837, 1902. 
218 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

recent geologic age. This assumption necessitates dips of scarcely more than 200 feet · in 

the distance between the outcrops of the formation and the inner margin of the Pleistocene formations of the Gulf coast. This distance is so great that the dip of the formation 

would be negligible, and the hypothesis of . 

recent geologic age is not tenable if there is a 

well-defined dip toward the coast. 

It is evident from the following detailed 

statements that the formation as a whole does 

not dip in a single direction. The prevalent 

direction of dip is southeast in central Louisiana and west of south in east-central 

Mississippi, the change of direction occurring 

near Mississippi River, where there was evidently an embayment that received the Catahoula sediments. 

EASTERN LOUISIANA . 

In discussing the stratigraphy along the 

Ouachita Harris 1 gives the dip of the Catahoula. 

sandstone in eastern Louisiana: 

Three miles south of Danville, at Rock Hill, as has 

already been stated, the base of the Grand. Gulf sandstone 

layers is 203 feet above tide. The fossiliferous Vicksburg 

beds in little ravines close by are from 60 to 70 feet below 

the sandstone layers; the intervening space is covered. 

Yet in the Harrisburg road perhaps 2 miles farther south 

thick sand beds were observed beneath the indurated 

ledges. These we would naturally place in the Grand 

Gulf stage. Ten miles southeast of Rock Hill, at . Catahoula Shoals, borings made by the United States Engineers 

indicate the presence of hard Grand Gulf layers to a depth 

of 128 feet above tide. In this direction, therefore, nearly 

due southeast, the dip is about 31 feet per mile. If, however, we take the approximate elevation of the lower beds 

of the Grand Gulf just across the river from Colfax as 110 

feet and note the distances and directions from each of 

these points and solve graphically for direction and amount 

of dip, we find the true dip to be S. 26° E. at the rate of 

34 feet per mile. 

The dip toward the southeast from Rook Hill 

to Catahoula Shoals as determined by Harris 

should have been a close approximation, but 

the elevation of the "hard Grand Gulf layers" 

at Catahoula Shoals as given by this author 

(" 128 feet above tide" ) is a mistake. The 

boring at Catahoula Shoals did not reach the 

base of the formation, though it was probably 

not far above the base, and the bottom of this 

boring is reported by the Army Engineers 2 to 

1 Harris, G. D., Tertiary geology of the Mississippi embayment: 

Geology of Louisiana, pt. 6, p. 29, 1902. 

2 Chief of Engineers, U.S. Army, Rept. for 1902, pt. 2, p. 1560. 

be 186.45 feet below sea level. If the elevation 

of the base of the formation at Rock Hill is 

60 feet less than 203 feet, as may perhaps be 

inferred from Harris's statement, the dip 

amounts to 329.45 feet in 10 miles, the distance 

given by Harris, or about 33 feet to the mile. 

The true dip may be somewhat greater or 

smaller, the amount of error depending on the 

distance between the bottom of the boring at 

Catahoula Shoals and the base of the formation 

and also on the distance between the assumed 

base of the formation at Rock Hill and the true 

base. 

The base of the Catahoula sandstone on the 

Louisiana & Arkansas Railway 27 miles west 

of north from Pineville is 190 feet above sea 

level. A well drilled at Pineville, where the 

surface is 120 feet above sea level) reached the 

base of the Catahoula at a depth of 927 feet. 

The dip of the formation between these two 

places i~ therefore about 37 feet to the mile 

in a direction slightly east of south. 

By joining the point where the base of the 

formation is exposed on the Louisiana & 

Arkansas Railway with Pineville and Catahoula Shoals the maximum dip for eastern 

Louisiana is found to be about 38 feet to the 

mile and the direction S. 24 ° E. 

WESTERN LOUISIANA. 

In western Louisiana the Catahoula sandstone has a steeper dip, but the determination 

is less accurate than in eastern Louisiana. 

The approximate position of the base of the 

formation at Leesville, as determined from an 

incomplete set of samples from a well, is 524 

feet below sea level, and the base of the 

formation near Hornbeck is 320 feet above 

sea level. The ~stance between these places 

is about 16 miles, and the average dip is 

therefore about 53 feet to the mile in a direction east of south. 

SOUTHERN MISSISSIPPI. 

The base of the formation on Pearl River, 

in southern Mississippi, is approximately 220 . 

feet above sea level1 and in a well at Monticello 

it was reached at a depth of slightly less than 

800 feet, or about 590 feet below sea level. 

The distance from the outcrop of the basal 

beds on Pearl River to Monticello is about 40 

miles and the difference in elevation of the 
THE CATAHOULA SA~DSTONE. 

base of the formation is 810 feet. The dip 

between these two places is therefore about 

20 feet to the mile in a direction slightly 

east of south. Another computation 

based on the elevation of the base of 

the formation on the New Orleans Great 

Northern Railroad near Byran1 gave a 

result differing more than 1 foot to the 

mile. South of Byram the sandstone beds 

that occur near the base of the formation on this railroad have an elevation of 

265 feet above sea level. The base at 

Monticello being 590 feet below sea level, 

the descent between the two places 

amounts to 855 feet. The distance between the two points is 40 miles, and 

this gives an average dip of 21! feet 

to the mile, in substantially the same 

direction as between Pearl River and 

Monticello. 

At . Sanford the top of the Vicksburg was encountered in a well at a 

depth of 591 feet, or 375 feet below 

sea level. By joining Sanford with Mon-

. ticello and with the point where the 

base of the formation is exposed on 

Pearl River, the general dip in southcentral Mississippi was computed at 23 

feet to the mile in a direction about 

18° west of south. These figures are 

believed to be substantially correct, 

though a small amount of error in this 

and similar ' computations is to be 

expected because of errors in locating 

the exaot points where the base of 

the formation has been observed and 

also because the maps used in making 

measurements for the computations were 

on a small scale and more or less inaccurate. 

TIDCKNESS. 

The Catahoula sandstone is comparatively thin in a large portion of the area 

where it is exposed, but in central Louisiana it may reach a maximum thickness 

of 800 feet. The best data for determining the thickness of the formation are 

afforded by samples of drillings obtained 

from wells. Of somewhat less value are 

records of materials penetrated in well 

30830°--17----15 

l'%j 

Q 

q 

~ 

t'l 

to.:> 

~ 

I 

m 

<l> 

g. s· 

~ 

8, 

; 

<l> 

0 

~ 

c 

~ 

p 

~ 

§ 

0 

~ 

i:::l 

~ 

l'%j 

0 

.... 

~· 

8, 

' (ll 

(!) 

g. 

s· 

~ (ll 

<l> 

(!) 

::n 

~ (!) 

.... 

<:To 

? 

~ 

"' 

"' 

0 

u; 

N 

0 

N 

U1 

~ 

~ 

Q;l 

~ 

~ 

~H:rlt-'-' Pineville,La.. 

~ .... 

~ 1:1; 

Catahoula a Sboals,La.. 

Near Brookhaven, Miss. 

!".., Monticello, Miss. 

219 

Sixmil.es south ofByram,Miss 

. (On Pearl River:) 

:Z">j 
220 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

borings, though where such records are carefully kept, with full descriptions of strata, the 

approximate limits of the formation can be 

~:f 

recognized because it is more 

sandy than either the underlying or overlying beds. 

In a well at Monticello, 

Miss., a clay bed 300 feet in 

thickness overlies the Catahoula sandst0ne. The base 

of this clay lies at a depth of 

380 feet, and marine shells, 

from their description undoubtedly Vicksburg, were 

encountered at about 800 

~ feet. This gives a thickness 

t ~ of 420 feet. Another way 

. ~ 'C of determining the thickness 0 § ~- ~ in this portion of :Mississippi 

~ is by multiplying the rate of 

~ dip to the mile (20 feet) by 

~ the width of the outcrop in 

~ miles. This computation 

~~ · .S gives a thickness of nearly l "' 

0 

0 

ot) 

· '8 400 feet for the formation. 

fi5 

d 

'3 

Q 

~ 

.... 

0 

Farther west, near Natchez, 

a well penetrated 550 feet 

of sands, sandstones, and 

clays belonging to this formation . 

.... 

0 

~ From Pearl River east-

~ ward the Catahoula sandstone thins gradually, and 

near IIealing Springs, Ala.,it 

is probably less than 200 feet 

thick, though not enough information is available to determine the full thickness in 

eastern Mississippi and western Alabama. WestofPearl 

River the Catahoula sandstone thickens, but it is not 

known whether the increase 

is at a uniform rate. In eastern Louisiananosatisfactory 

section giving the entire 

thickness of the formation 

could be obtained. On the 

?: ......-r-ro assumption that the dip is 

~aa;ov uniform in this area the 

thickness may be computed approximately 

by multiplying the width of outcrop in 

Catahoula PariSh, which is 16 miles, by the 

average dip, 33 feet to the mile. This gives 

a thickness of 528 feet, which is slightly less 

than the maximum thickness shown by some 

wells in the central part of the State. 

The samples from the Pineville well, in central Louisiana, show a thickness of 800 feet of 

the Catahoula sandstone, though this may include a portion of the overlying Hattiesburg 

clay. The character of the samples indicates 

that the Jackson formation occupies at least 

100 feet of this well section. The Catahoula 

is nearly twice as thick at this locality as at 

Monticello. The increase toward the west is 

due to the fact that in that area the Catahoula 

represents the time interval of the Vicksburg 

limestone. In other words, while the limestones and marls composing the Vicksburg 

were being formed in eastern Louisiana . . and 

east of Mississippi River, a great thickness of 

sandy detritus was being deposited in · central 

Louisiana. 

In western Louisiana and eastern Texas 

there is little direct information as to the thickness of the Catahoula sandstone, but it is inferred that the formation thins in that direction because the samples examined from the 

well at Leesville, together with the log of the 

well, showed a thickness of only about 600 

feet of the sandstone. 

ORIGIN. 

All geologists who have studied the Catahoula 

sandstone have agreed that it is nonmarine, 

their conclusions being based largely on the 

absence of remains of marine organisms and 

the presence of fossils of nonmarine origin, such 

as leaves and a few scattered fresh-water shells 

of unios and anodonts, together with the ch~racter of the materials constituting the formation. The presence of a large amount of lignitized wood and numerous thin layers of lignite gives evidence of deposition in swamps, 

and the character of the materials themselves 

indicates deposition near the strand line, where 

there are many variations in the kinds and 

arrangement of sediment. (See Pl. LIII.) 

The formation is on the whole sandy because 

of the influx of swift currents bearing coarse 

detritus, though the presence of layers arid 

lenses of more or less sandy clay shows that 

the currents were at times gentle, and, on the 

other hand, the occurrence of pebbles of mod-
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE Llll 

A. CROSS-BEDDED SANDS AND CLAYS, 3 MILES SOUTHWEST OF WAYNESBORO, MISS. 

B. SANDSTONES AND CLAYS, MISSISSIPPI SPRINGS, EAST OF RAYMOND, MISS. 

Photograph by 0. B. Hopkins. 

LITHOLOGIC CHARACTER OF THE CATAHOULA SANDSTONE. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE LIV 

A. LIGHT-COLORED SANDSTONE AND DARK-COLORED B. MASSIVE BEDS OF QUARTZITE. 

QUARTZITE. 

LITHOLOGIC CHARACTER OF THE FAYETTE SANDSTONE. 
THE CATAHOULA SANDSTONE. 221 

erate size in the sands indicates that at times 

the streams had a high velocity. 

A peculiar type of bedding may be seen in 

one of the exposures in central Louisiana, between Chopin and Galbraith. (See fig. 21.) 

The upper bed consists of typical Catahoula 

sandstone with thin lenses of clay; the lower 

bed is of clay, and between these beds is a 

third, consisting of lenses of sand inclined 

steeply and separated by clay. The structure 

here resembles that of a delta, with the be·ds 

relatively thin and the sand lenses inclined 

toward the southeast away from the old shore 

line. 

It has generally been assumed that the conditions of Catahoula time were estuarine and 

that the currents of water were sluggish. The 

theory of estuarine origin for a portion of the 

formation is apparently confirmed by the character of the deposits and by the fact that they 

contain more or less gypsum, which was doubtless deposited by evaporating saline waters. 

The hypothesis sometimes advanced that the 

currents of water entering the estuary were 

sluggish does not appear tenable, for the formation is made up largely of coarse sediments, 

though marked fluctuations are indicated by 

the numerous alternations of clays, sands, and 

fine conglomerates. 

Goldman 1 has presented petrographic evidence that the Catahoula sandstone of Texas 

contains a large percentage of well-rounded 

wind-blown sand. This may be a confirmation 

of the view that the deposits were laid down 

near the strand line, where they were moved 

about by the waves and in many places blown 

about on sand plains or perhaps in a few 

places built into dunes and ridges. . The presence of leaves and fragments of wood of species such as grow in moist tropical climates, 

however, indicates that there was an abundance 

of moisture near the coast and probably a 

luxuriant tropical vegetation. Such conditions do not harmonize with the assumption of 

extensive wind erosion along the strand line, 

and it is therefore reasonable to suppose that 

the rounding of the sand grains was mostly 

accomplished before the sands were brought to 

their present position, though a small amount 

1 Goldman, M. I., Petrographic evidence on the origin of the Catahoula 

sandstone of Texas: Am. Jour. Sci., 4th ser., vol. 39, pp. 261-287, March, 

1915. 

of wear may have resulted from wind erosion 

along the coast. 

The presence of a large amount of unweathered feldspar suggests that the sands had not 

been subjected to long-continued weathering 

in a moist climate. 

The great thickness of the sandstones in the 

territory adjacent to Red River indicates 

changes toward the headwaters of that stream, 

probably affecting all the streams in the region 

of the Great Plains. The most probable explanation is that the streams flowing across the 

Great Plains were rejuvenated by a regional 

uplift. This would account for the great influx 

of sand into the Tertiary sea, and it might be accompanied by an arid climate for some distance 

east of the Continental Divide, provided the 

uplift raised the mountains high enough to cut 

off a portion of the moisture. This would furnish favorable conditions for wind action and 

for the accumulation of the unweathered feldspar which is so abundant in the sand. Conclusions of this character must for the present 

be regarded as tentative, because the petrographic studies have been confined to samples 

of sandstone from Texas, and these have not 

been compared with samples from other localities. The conditions of deposition may have 

been somewhat different farther east, where the 

sediments were derived either wholly or in part 

from more humid regions, and the conditions 

may have changed while the sands were being 

laid down. 

STRATIGRAPHY. 

DIFFICULTIES OF STRATIGRAPHIC WORK. 

Most of the exposures of the Catahoula sandstone are of sHght value for stratigraphic study 

because they have been reduced by the processes of weathering to yellow or orange-colored 

sands and clays that resemble those found 

nearly everywhere on the Coastal Plain. This 

similarity in lithologic character is explained 

by the fact that the materials in most of the 

formations were derived from the same sources 

and on weathering assume the same general 

appearance. Many of the formations showing 

this characteristic were deposited under conditions suffipiently diverse to make them distinct in lithologic appearance, so that they can 

be differentiated where they are unaltered. 
222 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Stratigraphic work is further confused by the 

relations of the different beds resulting from the 

conditions of sedimentation. Thus the contact 

between the sands and the clays is nearly 

everywhere irregular, giving the appearance of 

unconformity, but the irregularities are due 

chiefly to the fact that the materials were deposited by shifting currents of varying velocity; 

During periods of uninterrupted deposition by 

slow currents the sediments were mostly clay 

mixed with more or less organic matter derived 

in part from floating vegetation and in part 

from plants that grew in swamps and marshes. 

In some places chemical deposits were made in 

lagoons, but the rna j or part of the rna terial is 

detrital. With the incursion of flood waters 

conditions were altered, and the relatively even 

surface of the clays laid down by the quiet 

waters was eroded. The stronger currents left 

deposits of coarser material, such as sand and 

more rarely pebbles, and these coarse sediments 

were subsequently, when the floods subsided . . . ' buned beneath clay. Frequent changes in the 

conditions of deposition produced many alterations in the character of the sediments, with 

irregular lines of contact and marked discordance of stratification between the deposits of 

different kinds. In many places fragments of 

clay loosened from earlier deposits were more 

or less rounded and then incorporated with 

coarser materials, forming clay conglomerates 

or breccias. The final result of the varying conditions of sedimentation was a formation containing innumerable instances of lack of conformability between successive bed.:;. The evidences of unconformity may be seen in many 

sections and at almost any stratigraphic horizon 

from the top to the bottom of the formation 

being distributed throughout the area of out~ crop. As the formation is known from well 

records and samples of material obtained in 

drilling to be several hundred feet thick, it is 

clear that the unconformities are of local character and have no broad stratigraphic significance.· Failure to understand the meaning of 

the irregular contacts of materials in the Catahoula formation, together with an attempt to 

correlate outcrops solely on the basis of general 

lithologic character, has led to the inclusion of 

weathered portions of the Catahoula in what 

has been called the Lafayette formation. It 

;Should not be inferred, however, that the socalled Lafayette formation does not contain 

other beds besides those mention'ed. 

STRATIGRAPHIC RELATIONS. 

UNDERLYING FORMATIONS. 

VICXSBURG LIMESTONE. 

Hilgard, 1 who was the first geologist to map 

the extensive "Grand Gulf" deposits, considered the beds to be essentially horizontal, 

though he reported high local dips in different 

directions. From the supposed discordance · in 

dip between the Vicksburg limestone and the 

"Grand Gulf" sandstone he concluded that the 

two formations are not conformable. 

The dip of the Catahoula sandstone is discussed in detail on pages 217-219, where it is 

shown that in addition to a general seaward 

slope the formation has well-defined southerly 

dips converging toward Mississippi River, thus 

showing an inclination toward the center of the 

Mississippi embayment, which must have been 

at that time the 8ite of rapid sedimentation. 

The views of Smith and Aldrich 2 have been 

fully set forth in outlining their controversy 

with Dall. The differences between these authors are due to dissimilar methods of. work. 

In correlating exposures Smith and Aldrich relied largely on lithologic characteri&tics, and 

the similarity of materials led them to believe 

that a single formation extended across the 

edges of formations ranging in age from Eocene 

to Miocene or Pliocene. Dall, relying on the 

field observations of Johnson and others, together with the knowledge obtained from a 

study of the faunas of the Gulf Coastal Plain, 

reached conclu.Sions similar to those held by, 

Johnson, who, as early as 1893, had succeeded 

in differentiating four "phases" in what had 

formerly been called ''Grand Gulf." 

In southern Mississippi the Catahoula sandstone rests conformably on the Vicksburg limestone; in Alabama it rests conformably on the 

St. Stephens limestone, the upper part of which 

is of Vicksburg age. Sections that show a c'onstant relation between· the Vicksburg and the 

Catahoula sandstone have been noted at many 

places. A typical example is furnished by the 

, 1 Hilgard, E. W., The later Tertiaryofthe Gulf6fMexico: Am .Jour, 

Sci., 3d ser., vol. 22, p. 58, 1881. 

2 Smith, E. A., and Aldrich, T. H., The Grand Gulf formation: 

Science, new ser., vol. 16, pp. 835-837, Nov. 21, 1902. 
THE CATAI-IOULA SANDSTONE. 223 

exposures at Vicksburg, Miss., where the following section was measured: 

Section at Vicksburg, Miss. 

Catahoula sandstone (nonmarine): Feet. 

relations of the Catahoula to subjacent formations and makes a definite statement of the 

direction and the amount of dip. It is clear 

that he does not agree with Hilgard's statement 

that the formation is essentially horizontal. Coarse friable gray sandstone with local lenses 

of quartzite and some interbedded gray clay. 

Blue clay, weathering drab, interbedded and 

interlaminated with gray sand and friable 

sandstone (exposed at intervals) ......... . .. . 

The following section shows the relation between the Catahoula sandstone and the Vicksburg limestone in Catahoula Parish, the type 35 locality of the Catahoula sandstone. 

20 

Vicksburg limestone (marine): 

Chocolate-colored calcareous clay ............ . 

Fine gray to drab sand ...................... . 

18 

6 Section in wagon road near Rosefield, Catahoula Parish, La., 

Fine sandy marl, very fossiliferous ........... . 40 

East of Vicksburg many generalized sections 

were obtained, but details are not available at 

many places because of poor exposures. The 

marl bed that forms the basal mem her of the 

foregoing section is exposed on Pearl River 

south of Byram, where it is overlain by darkcolored calcareous clays and these in turn are 

overlain by interbedded clays and sandstones of 

the Catahoula formation. Similar conditions 

were observed on Leaf River near Blakney, 

:Miss., where the same marl bed is overlain by 

about 40 feet of clay, massive and calcareous 

near the base and interbedded with gray sandstones in the upper portion of the exposures. 

On Chickasawhay River near the wagon bridge, 

3 miles southwest of Waynesboro, the marl bed 

is overlain by calcareous clays and marls, with 

a bed of oyster shells. The contact is not well 

shown, but small exposures near Triggs Ferry, 

about lt miles west of Waynesboro, show that 

the drab clays and sands of the Catahoula sandstone rest on an even surface of the clays of the 

Vicksburg limestone. Farther east, in Alabama, 

the relation of the Catahoula sandstone to the 

Vicksburg deposits is the same as in Mississippi, 

a bed of calcareous clays lying between the upper fossiliferous beds of the Vicksburg and the 

interbedded sands and clays of the Catahoula. 

These relations are exhibited south of Manistee, 

near Manistee Junction, and at several other 

places. 

West of Mississippi River, in Louisiana, the 

Catahoula sandstone rests unconformably on 

the Vicksburg limestone, according to Harris 

and Veatch/ who cite Hilgard as authority 

for the statement. In a subsequent report 2 

Harris gives in more detail his views as to the 

1 Harris, G. D., and Veatch, A. C., Geology of Louisiana, pt. 5, p. 95, 

1899. 

2 Harris, G. D., Geology of the Mississippi embayment: Geology of 

Louisiana, pt. 6, p. 28, 1902. 

in sec. 28, T. 11 N., R. 5 E. 

Yellow sand .................................... . 

Yellow marl containing Orbitoides mantelli and Pecten poulsoni in calcareous concretions ........... . 

Yellow sand .................................... . 

Yellow clay ..................................... . 

Yellow sand and friable gray micaceous sand rock 

Feet. 

15 

2 

10 

18 

which weathers to yellow incoherent sand........ 25 

Red clay........................................ 6 

No. 1 of this section is a typical weathering 

product of the Catahoula sandstone, and from 

the presence of Vicksburg fossils in No. 2 it, 

together with the underlying material, would 

be placed in the Vicksburg. However, Nos. 

3 to 6 are lithologically similar to the Catahoula 

sandstone, and it is apparent that the two formations are interbedd3d at this ]ocality. 

Farther west the Vicksburg is entirely replaced 

by the Catahoula sandstone. In addition to 

being interbedded with the Vicksburg the Catahoula sandstone contains beds of calcareous 

clay at many localities. The presence of such 

a clay bed is shown in the following section: 

Section of Catahoula sandstone at Harrisonburg, La. 

Gray sand ...................................... . 

Yellow and orange-colored sand containing a few 

scattered pebbles arranged in thin layers ....... . 

Yellow sand and graveL ........... -...... , ..... .. 

Yellow sand grading downward into gray sandstone 

with a thin lami'rue of clay ................... .. 

GraveL ........................................ . 

Interbedded gray clay and sandstone, some layers 

showing cross-bedding ......................... . 

Dark-gray clay with greenish tinge where fresh ... . 

Interbedded gray sandstone and clay ............. . 

Dark-gray clay .................................. . 

Yellow sand .................................... . 

Gray sandstone ................................. . 

Massive green clay .............................. . 

Massive green sandstone containing pebbles; surface 

weathered to light yellow .................... .. 

Green clay .................................... . 

Massive gray sandstone ......................... . 

Massive green clay .............................. . 

Feet. 

2 

8 

3 

2 

2 

8 

10 

2 

4 

4 

5 

5 

4 

2 

4 

15 
224 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

The lowest bed of.clay is distinctly calcareous 

where fresh, the surface of tlie layers and cracks 

in the beds being covered with numerous 

rosettes of calcium carbonate. The sandstone 

overlying it is also calcareous, though the percentage of calcium carbonate is smaller than 

in the clay. 

FAYETTE SANDSTONE. 

Veatch 1 included in his Catahoula formation in central and western Louisiana beds that 

pass laterally into typical clays and thinbedded sands and sandstone of the Jackson 

formation. This portion of the formation is 

in the present report correlated with the Fayette sandstone of Texas. Harris 2 described 

the relations of these sandstones to the Jackson formation in western Louisiana as unconformable and regarded the poorly preserved 

remnants of marine fossils in the sandstone as 

survivors from the Jackson epoch. Recent 

study in western Louisiana shows that the 

irregular contact described by Harris is like 

those occurring at most places where coarse 

sandstones have been deposited on clays, the 

irregularities in the surface of the clay being 

such as are commonly produced ·by currents 

bearing coarse detritus. 

The Fayette sandstone of western Louisiana 

has a thickness of 100 to 200 feet. It is more 

quartzitic than the Catahoula sandstone (see 

Pl. LIV) and is locally interbedded with clays 

that are darker and more calcareous than the 

clays of the Catahoula. The two formations 

differ in origin. Both contain silicified wood 

and imprints of fossil leaves, and in addition 

the Fayette sandstone contains many imprints 

of marine fossils. The Catahoula sandstone 

is apparently nonmarine, being devoid of traces 

of marine fossils exoept where it merges with 

the Vicksburg limestone. 

The facts outlined above lead to the conclusion that the Catahoula sandstone of Mississippi 

and Alabama is conformable with the underlying Vicksburg limestone (represented in Alabama in the upper part of the St. Stephens 

limestone), because if the Vicksburg had been 

eroded before the deposition of the Catahoula 

the uppermost layers of the Vicksburg would 

1 Veatch, A. C., Geology and underground water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 

pp. 42-43, 1906. 

2 Harris, G. D., Geology of the Mississippi embayment: Geology of 

Louisiana, pt. 6, p. 28, 1902. 

be missing in some of the sections. In eastern 

Louisiana the Catahoula sandstone dovetails 

with the Vicksburg, and in western Louisiana 

it is conformable with the Fayette sandstone. 

These facts indicate that the deposition of the 

Catahoula followed that of the underlying 

marine formations without a stratigraphic 

break and that it began in Texas and western 

Louisiana and was gradually extended eastward to Mississippi. In Mississippi and Alabama its deposition began at the end of the 

Vicksburg epoch and extended across the 

entire area where the Catahoula . is exposed. 

However, brackish-water conditions persisted 

in places for a short time after the deposition of 

the upper marl bed of the Vicksburg, as 

shown by the oyster bed near Waynesboro, 

Miss. 

OVERLYING FORMATIONS. 

HATTIESBURG CLAY. 

The Catahoula sandstone is oyerlain conformably by the Hattiesburg clay, of Oligo:-

cene age. This formation ranges in thickness 

from 300 to 350 feet in Alabama and Louisiana 

and to a maximum of 450 feet in central and 

western Mississippi. It consists of massive 

blue and gray clays with subordinate amounts 

of sands and sandstones. Locally the clay 

beds are consolidated into hard ledges, though 

this rock is not restricted to any one formation, being found in all the Oligocene and 

Miocene deposits of the Gulf embayment. In 

some places the .clays contain fragments of 

lignitized wood and imprints of fossil plants. 

A deposit of this character a few miles east of 

Hattiesburg; Miss., near McCallum, furnished 

some identifiable remains of fossil plants. At 

Hattiesburg, the type locality, the clays are 

exposed in the banks of Bowie Creek and Leaf 

River and in the lower portions of the hills 

that border these streams. 

The name Hattiesburg was first used by 

Johnson, whose definition is given on page 211. 

The type locality of the Hattiesburg clay is the 

same as the type locality of Johnson's Hattiesburg phase or formation/ but a brief 

statement of the significance of the new term 

Hattiesburg clay is given here because it is 

used to include the portion of Johnson's Fort 

Adams or Ellisville phase that extends from 

a Johnson, L. C., The Miocene group of Alabama: Science, vol. 21, 

pp. 90-91, 1893. 
THE CATAHOULA SANDSTONE. 225 

the mouth of . Okatoma Creek eastward past 

the falls on Leaf River near Eastabutchie to 

Chickasawhay River between Winchester and 

Waynesboro. 

The Hattiesburg clay is readily recognizable 

from central Alabama, where it merges into 

the more sandy fossiliferous beds of the Alum 

Bluff formation, westward to eastern Texas. 

In western Louisiana and eastern Texas it is 

the lower portion of what Veatch 1 mapped as 

Fleming clay. The relation of the overlying 

Miocene to the Hattiesburg clay is unconformable, and this permits the separation of 

what has been called the Fleming clay in 

Louisiana and along the eastern border of 

Texas into two parts. The lower part, which, 

from its stratigraphic relations is included in 

the Hattiesburg clay, is more sandy and much 

less calcareous than the overlying Miocene 

clays. 

PASCAGOULA CLAY. 

A series of blue, green, and gray clays, locally 

calcareous, with interbedded sands and more 

rarely sandstones, lying unconformably above 

the Hattiesburg clay, has been called the 

Pascagoula clay. This formation is locally 

fossiliferous and has furnished remains of 

marine or brackish-water invertebrates at 

Shell Bluff and Givhens Landing, on Chickasawhay River, Miss., and in numerous wells in 

the southern part of the State. A somewhat 

different fauna has been obtained from the 

formation at Pine Prairie and southwest of 

Alexandria, La., and at Burkeville, Tex. The 

formation ranges in thickness from about 250 

feet in Alabama to 450 feet near Mississippi 

River in Louisiana and along the Gulf coast in 

Mississippi. In western Louisiana and eastern 

Texas the thickness has not been accurately 

determined but it is thought to be about 250 

or 300 feet. Local variations in thickness are 

. to be expected, because the Pascagoula clay is 

overlain unconformably by sands and clays of 

Pliocene age and rests unconformably on the 

Hattiesburg clay. 

The Pascagoula clay differs from Johnson's 

Pascagoula phase or formation 2 by including 

the portion of his Fort Adams or Ellisville 

phase extending from Tunica, La., to Columbia, 

Miss. The type locality is, however, the same, 

1 Veatch, A. C., Geology and underground water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 

pp. 43-44, 1906. . 

2Johnson, L. C., The Miocene group of Alabama: Science, vol. 21, 

pp. 90-91, 1893. 

and the difference is largely due to a more 

thorough understanding of the distribution of 

the formation. West of Mississippi River the 

Pascagoula clay extends across southern Louisiana and eastern Texas and includes the upper 

portion of what Veatch 3 called the Fleming 

clay. CITRONELLE FORMATION. 

The Pascagoula and Hattiesburg clays and 

the Catahoula sandstone are in places overlain by sands, gravels, and clays that from their 

fossil flora (identified by E. W. Berry) are 

known to be of Pliocene age. These deposits, 

which heretofore have been called Lafayette 

formation, Orange sand, etc., have recently 

been named the Citronelle formation/ from the 

town of Citronelle, in northern :Mobile County, 

Ala. The formation consists of yellow and 

red clays and sands, with lenses and layers of 

gravel in which the pebbles range from a 

fraction of an inch to several inches in diameter. 

Subangular chert is the most abundant constituent of the gravel, though it contains 

everywhere a varying percentage of rounded 

quartz pebbles. 

The Citronelle formation, which is largely 

nonmarine, varies greatly in thickness, ranging 

from a minimum of 30 feet where it overlies 

the Catahoula to over 150 feet where it rests 

on the outcropping edge of the Pascagoula and 

to a maximum of 400 feet nearer the coast, 

where it underlies the Pleistocene deposits. 

The relation of the Citronelle to both the 

overlying and underlying formations is unconformable, a fact which accounts for some 

of the variations in thickness. Other variations are explained by the character of the 

surface of the formation, which is composed of 

a series of plains diminishing in elevation 

toward the coast and toward the axes of the 

principal valleys that cross the formation. 

CORRELATIONS. 

The Oligocene series of western Florida includes in descending order the Alum Bluff 

formation, the Chattahoochee· formation, and 

the Marianna limestone. The Marianna is of 

Vicksburg age. The marine Chattahoochee 

formation passes westward in Alabama by 

gradation through fossiliferous marls into 

3 Veatch, A. C., Geology and underground water resources of northern 

Louisiana and southern Arkansas: U. S. Geol. Survey Prof. Paper 46, 

pp. 43-44, 1906. 

4 Matson, G. C., U.S. Geol. Survey Prof. Paper 98, pp. 167-192, 1916 

(Prof. Paper 98-L). 
226 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

the nonmarine sandstones and clays of the 

Ca tahou1a sandstone. The equivalence of the 

Chattahoochee formation and that portion of 

the Catahou1a sandstone lying east of Mississippi River is further shown by the relations of 

these formations to those above and below 

them. The Chattahoochee formation of 

Florida conformably overlies the Marianna 

limestone, the Florida representative of the 

Vicksburg limestone/ and the Catahou1a sandstone of Alabama and Mississippi rests conformably on the Vicksburg limestone. 

The Chattahoochee formation is overlain 

conformably by the Alum Bluff formation, and 

the Catahoula sandstone is overlain conformably by the Hattiesburg clay. The equivalence 

of the Alum Bluff formation and the Hattiesburg cl~y has been established by tracing their 

physical continuity and by fossil plants identified by E. W. Berry.2 

The correlation of the Catahoula sandstone 

west of Mississippi River has already been explained, but it may be summarized by stating that in this area the Catahou1a includes 

sandstones and clays equivalent not only to 

the Chattahoochee formation, but also to the 

Vicksburg limestone, rests conformably on 

the Jackson formation and the Fayette sandstone, and is conformably overlain by the 

Hattiesburg clay. 

The table opposite page IV shows the correlation of the Tertiary formations in the 

Gu1f States. 

CONCLUSIONS. 

The Catahoula sandstone consists of alternating sandstones and sands, with lenticular 

beds of clay, the · arenaceous sediments predominating. Conglomerates are ra.re_, though 

small quartz and chert pebbles occur in some 

of the layers of sand, and pebbles of clay a1e 

found at many localities and at different stratigraphic horizons. The formation is nonmarine but was deposited near the strand line, 

where small bodies of brackish water were 

isolated and, on evaporation, formed precipitates of salt and gypsum. The streams that 

transported the materials now constituting 

the formation had varying velocities and made 

1 Cooke, C. W., unpublished notes. 

2Index to the stratigraphy of North America: U. S. Geol. Survey 

Prof. Paper 71, p. 744, 1912. 

deposits ranging in texture from clay to finegrained conglomerates. The floods that transported the coarse materials eroded the surfaces 

of existing clay deposits, thus forming irregular 

contacts and incorporating more or less rounded 

fragments of the clay in the sands. The fossils, 

which are rare, are mostly leaves, but molluscan 

remains occur at a few places. One of these 

localities is at Chalk Hills, near Rosefield, La., 

where shells of unios ( ~) are found in a sandstone, and another is in a cut on the Texas 

& Pacific Railway, 1 mile east of Lena, where 

fragments of oyster shells occur in a lens of 

limestone. 

Weathering of the formation produces red, 

yellow, and mottled sands and clays that have 

commonly been classed as Orange sand and 

plaoed in _a separate formation called the 

Lafayette. This classification has resulted 

from the existence of numerous local unconformities and the general resemblance of these 

weathered sands and clays to similar materials 

occurring in other portions of the Coastal Plain. 

The sections in the vicinity of Harrisonburg 

and Rosefield, La., show that the sandstones 

and clays of the Catahoula are interbedded 

with the lower Oligocene limestones and marls 

(Vicksburg limestone). Farther west in Louisiana they replace all ·the marine lower Oligocene beds. Similar sandstones (Fayette 

sandstone) containing marine fossils are the 

equivalents of some of the calcareous and fossiliferous beds of the Jackson formation in 

western Louisiana and represent nearly all 

of the Jackson in central Texas. These facts 

account in part for the increased thickness of 

the formation in central Louisiana, amounting 

to several hundred feet, and explain the form 

of the outcrop of the formation in the Mississippi embayment and the .Red River valley. 

The belief that the Catahoula sandstone is 

essentially horizontal, which, if correct, would 

be a fatal objection to the merging of the 

Catahou1a and older formations, is shown to 

be. an error. Information that was not available at the time of the early examinations 

shows clearly that the dips of the Catahoula 

range from slightly more than 21 feet to the 

mile · in east-central Mississippi to about · 38 

feet in central Louisiana and are probably even 

greater than 50 feet near the Louisiana-Texas 

boundary.