UNITED STATES DEPARTMENT OF THE INTERIOR 

J. A. Krug, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

Water-Supply Paper 968-D

GROUND-WATER EXPLORATION IN

THE NATCHITOCHES AREA

LOUISIANA

BY

J. C. MAHER AND P. H. JONES

Prepared in cooperation with the

LOUISIANA GEOLOGICAL SURVEY and the

CITY OF NATCHITOCHES

Contributions to the hydrology of the United States, 1944 

(Pages 159-211)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : W49

For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C.

Price 25 cents

CONTENTS

Page.

Abstract.....-__________________..-___--____---__________--___--_- 159

Introduction. ______________________________-_.._-_____________-.__- 159

Exploratory program_____________________________________________ 160

Method of test drilling-....,____-_.____-_--._..___._....... 160

Sampling methods.____________________________________________ 162

Drillers' logs,.._______________________________________________ 162

Electric logs.__..______-_-_...-_--._.--__-.-.-.__-_.__...--___ 163

Self-potential curve________________________________________ 163

Resistivity curve____._.__-_-_---__--___--__-___-_-___--___ 164

Interpretation_-_______--_-----_-___-_-_-_-___-_-___-__._ 165

Drill-stem tests.________-_-__----___-________-__---_--_________ 166

Results of exploration_________-__-__--__-____--_-___-________ .. 167

General geology__________-__________-_-__-_--_--__--_-_-___-______ 167

Structural geology.________________________________________________ 169

Quality of water_______-__-_--____--_-__.._-_----_--______-_-___-_ 173

Geologic formations and their water-bearing properties.________________ 174=

Eocene series_______________-___-__-___--____----_--_-_________ 174

Wilcox formation_____________---_-____-___-____-______-___ 174

Claiborne group._____-_-_______-_-_-_---_----_--_-____-__- 177

Cane River formation.._---_._._-_-_____-_-.___________ 177

S">arta sand_._________________________________________ 177

Cook Mountain formation._____________________________ 179

Cockfield formation._-______._____-___-_-__________--__ 181

Pleistocene and Recent series___________________________________ 181

Summary and conclusions-___-_-_-__-__--________--__-____________- 182

Index.______-___________-__-___---_--_-___-____-____._...._ 211

ILLUSTRATIONS

Pace.

PLATE 3. Geologic cross sections in the Natchitoches area, Louisiana. In poeket 

FIGURE 53. Map showing location of wells in the Natchitoches area,

Louisiana._________--_-----------_-_-_-______________ 161

54. Sketch map showing topography at Natchitoches, Louisiana. 168

55. Structural map of Natchitoches area contoured on top of the

Wilcox formation.____________________________________ 170

TABLES

Page. 

TABLE 1. Outline of stratigraphy in Natchitoches area, Louisiana_________ 185

2. Records of wells in the Natchitoches area, Louisiana__________ 186

3. Partial analyses of water samples from wells in the Natchitoches

area, Louisiana______--------_-_----_-_-__---_-_________ 190

4. Logs of wells in the Natchitoches area, Louisiana..___________ 191

6. Mechanical analyses of sand samples from wells in the Natchitoches area, Louisiana___.--____-____-_________.__.____ 208

in

I

GROUND-WATER EXPLORATION IN THE NATCHITOCHES

AREA, LOUISIANA

BY J. C. MAHER AND P. H. JONES

ABSTRACT

The water supply of the city of Natchitoches has been obtained for many years 

from shallow wells screened in fine-grained sands of the Wilcox formation. These 

sands have been locally overdeveloped, and the supply of water stored in 

the sands has been depleted gradually as the recharge from rainfall has failed year 

by year to equal the withdrawals by wells. An exploratory program designed to 

locate an adequate supply of ground water was initiated in the fall of 1943 by the 

city of Natchitoches. This program, directed by the Geological Survey, United 

States Department of the Interior, included the drilling, electric logging, and 

testing of nine exploratory wells which penetrated water sands of the S'narta sand 

and the Wilcox formation. An ample supply of soft potable water was found in 

these formations south of the city.

Geologic and hydrologic data obtained from the test drilling suggest that the 

city of Natchitoches may be situated upon a downthrown fault block defined on 

the southwest by a fault along Youngs Bayou and on the southeast by a fault 

extending from Old River toward Cane River Lake. Salt water, unlike connate 

sea water in composition, is present in the sands underlying most of the city. 

A similarity of topographic, geologic, and hydrologic conditions in this area to 

those in salt-dome areas in nearby parishes is evident.

The Sparta sand and the upper sands of the Wilcox formation crop out in a 

narrow band extending from Natchitoches westward into Texas. Moderate 

supplies of soft water are available from these sources. The city of Natchitoches. 

should be able to obtain as much as 1,000,000 gallons a day from tl ree to fiveproperly developed supply wells screened in these sands in sees. 10, 56, and 57, 

T. 8 N., R. 7 W. Additional water for increased future needs may I 3 obtained: 

by extending this well field to the west.

INTRODUCTION

Ground-water investigations were begun in Natchitoches in March 

1941 by the Geological Survey, United States Department of the 

Interior, in cooperation with the Louisiana Department of Conservation and the city of Natchitoches, to determine the advisability of 

drilling additional water wells within the city limits. This study, 

made by T. B. Stanley, Jr., was completed in September 1941, and 

the results indicated that, although large quantities of hard water are 

available from the Recent alluvium of the Cane River flood plain, 

little additional soft water can be obtained from wells within the city 

limits.

159
160 CONTRIBUTIONS TO HYDROLOGY, 1944

After a severe water shortage during the very dry summer and fall 

of 1943, the city of Natchitoches decided to undertake a ground-water 

exploration program in the area south and east of the city before 

giving further consideration to a proposal to impound surface water 

in the nearby swamp known as Sibley Lake. If adequate supplies 

of soft ground water could be found within a distance of 5 miles, the 

construction of three to five wells and the necessary pipe line would 

be economically feasible. The test drilling was paid for entirely by 

the city of Natchitoches but was directed by the authors at the request 

of the city officials. This report summarizes and interprets the information obtained during the testing program, together with that from 

records of previously drilled wells, and offers suggestions for the 

development of a new well field.

Acknowledgment is made of the aid and cooperation of Mayor 

Edwin McClung, G. H. Pierson, A. F. Ortmeyer, and S. L. Perry, 

of the city of Natchitoches. L. P. Blevins, well contractor, gave 

whole-hearted cooperation in obtaining necessary data, and R. T. 

Wade, Schlumberger Well Surveying Corp., offered helpful suggestions 

in the interpretation of the electric logs. The writers are indebted 

to O. E. Meinzer, of the Geological Survey at Washington, and J. 

Huner, Jr., Louisiana State geologist, for reviewing this report.

EXPLORATORY PROGRAM

The exploratory program in the Natchitoches area consisted of the 

drilling, electric logging, and testing of nine test holes located to the 

3outh and east of the city. (See fig. 53, wells 20-28.) Samples of the 

:sands and water contained therein were collected and aralyzed in the 

laboratory. The water level, temperature, yield, and drawdown were 

determined for each sand that appeared to have possibilities as an 

aquifer. Records from previously drilled wells and te?t holes were 

collected and assembled along with these data.

METHOD OP TEST DRILLING

The test holes, 6 inches in diameter and 339 to 991 fea-t deep, were 

drilled by hydraulic rotary methods, in which the drilling is accomplished by rotating a fish-tail bit on the end of a string of drill pipe 

while mud fluid is pumped down the drill pipe under pressure. The 

fluid carries the cuttings to the surface and seals the wpll of the hole. 

The hole usually is not cased during the drilling operations, although 

in some wells surface casing is required to prevent the si allow, poorly 

consolidated sands from caving. No surface casing wa? necessary in 

the test holes in the Natchitoches area. Both natural mud and Aquagel, a processed commercial drilling mud, were used in drilling these 

holes. Generally the Aquagel was not used as long as the natural
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 161

FIGUBE 53. Map showing location of wells in the Natchitoches area.'.Louisiara.
'162 - - CONTRIBUTIONS TO HYDROLOGY, 1944

mud was sufficiently viscous to hold up the wall of the hole through 

the water sands. The test holes were plugged with leavy mud and 

stiff clay upon completion of the testing.

SAMPLING METHODS

Specifications for the test drilling included a clause providing for 

the proper collection of samples at 10-foot intervals in each water 

sand. Whenever a sand was penetrated the drilling was suspended 

for 10 to 30 minutes (the length of time depending upon the depth 

of the hole and volume output of the mud pump) Trhile the mud 

was circulated to clean out the hole. When it was judged that all or 

most of the drill cuttings had been removed, the ditch returning mud 

'to the pits was cleaned out. Drilling was then resumed until 10 feet 

£f sand had been penetrated or the bottom of the sand reached by the 

tit. Again drilling was stopped and the mud was circulated for 10 to 

30 minutes before collecting sample portions at 5-foot intervals along 

the ditch. The combined sample portions were washed free of drilling 

mud, placed in clean quart size cardboard containers, labeled, and 

sent to the laboratory for mechanical analysis. Tie mechanical 

analyses of these samples were found to be very useful fc r comparative 

purposes, even though the rotary method of drilling does not permit 

accurate sampling of unconsolidated materials.

DRILLERS' LOGS

A record of the formations penetrated in each test hole was made 

t>y tjie drillers on the basis of drill cuttings, drilling time, action of the 

rotary table and mud pump, and changes in fluid level in the mud pit. 

The personal equation enters into such records to a considerable degree, 

and the use of such records requires some discretion. It has been 

found that the logs recorded by an experienced driller, familiar with 

both the drilling rig and the underground conditions, generally agree 

fairly well with the electric logs insofar as the principal water sands 

and hard rock layers are concerned. However, even the best drillers' 

logs do not show all of the small sand and clay beds that are often 

lumped together as "sand and shale," and in some wells even thick 

water sands have been overlooked.

Both drillers' logs and electric logs are desirable in water wells. 

The driller's log generally supplies accurate information, permitting 

the tentative correlation of water sands as the well progresses; the 

electric log made after completing the hole offers mechanically 

recorded evidence of the formations penetrated and gives considerable 

information on the character of the water sands and the water therein.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 163

ELECTRIC LOGS

After completing each test hole it was conditioned by circulating 

the drilling mud for a period of 1 to 3 hours to insure uniformity of 

mud in all parts of the hole and to build up a heavy mud cake in the 

water sands to prevent caving upon withdrawal of the drilling tools. 

As soon as possible after the removal of the drilling tools an electric 

log of the formations penetrated was made by one of the several commercial firms specializing in such services for oil wells.

An electric log is a record of the self-potential and apparent resistivity of the formations penetrated by the drilled hole. The selfpotential is recorded as the difference in electric potential between the 

formations in the hole and a point on the land surface. The apparent 

resistivity of the formations is determined by sending a current of 

electricity into the wall of the hole and measuring the rate of potential

 drop. The equipment used in making these measurements consists 

of a system of electrodes which are lowered into the hole; a multi-

 conductor cable spooled on a power-driven winch which raises or lowers 

the electrodes; a measuring sheave which records the depth of the

 electrodes; electrical measuring instruments and a source of electromotive force on the land surface connected to the electrodes by the 

multiconductor cable; and a plotting mechanism which records measured values of self-potential and resistivity on film.

SELF-POTENTIAL CURVE

The measured self-potential is shown on the left side of the film or 

electric log as a single trace, arbitrarily termed "the firrt curve." 

(See pi. 3.) In some instances an amplified version of this curve is 

also shown on the left side of the log, usually as a dashed line. The 

first curve has been generally considered to represent the algebraic 

sum of potentials generated by electrofiltration and electrochemical 

action during and after the drilling of the hole. 1 Recently, however, 

Lee 2 pointed out the possibility that natural earth potent'als might 

exist prior to drilling operations. Because any one of these potentials 

comprising the recorded self-potential may be either positive or 

negative under different conditions, it is extremely difficult to judge 

the relative magnitude of each from the first curve.

The electrofiltration potential is derived from the movement of fluid 

into or out of the formation due to differences in formational pressure

1 Deussen, Alexander, and Leonardon, E. O., Electrical exploration of drill holes: Am. Petroleum Inst., 

Drilling and production practice, pp. 48, 49,1935. Gillingham, W. J., Electrical logging in tl e Appalachian 

fields: Pennsylvania State College Min. Ind. Exper. Sta. Bull. 21, p. 4, 1937.

2 Lee, F. W., The possibility of electrical stratification in the earth as disclosed by surface measurements of 

currents and potentials: Am. Geophysical Union Trans., Terrestrial magnetism and electricity, pp. 383-399, 

1939.
164 CONTRIBUTIONS TO HYDROLOGY, 1944

and the weight of the mud column in the hole. When an electrolyte, 

such as the drilling fluid, is caused to flow through a permeable medium, 

such as a sand, an electromotive force is set up in the direction of the 

flow. This electromotive force is directly related to the permeability 

of the medium and to the pressure differential and electrical resistivity 

of the fluid. It is inversely related to the viscosity of the fluid.

The electrochemical potential is caused by two electrolytes (drilling 

fluid and formational water) of different ionic concentration coming in 

contact through a permeable medium (sand). The flow of the current 

is toward the more highly concentrated electrolyte, which may be 

either the drilling mud or the formational water. It is generally 

assumed that this potential adds to the electrofiltration potential, 

but it appears that this would not be true if the more concentrated 

solution is the drilling mud, as it sometimes is in water wells.

For many years it was thought that the electrofiltration potential 

was dominant, and for that reason the first curve wr.s commonly 

termed the "porosity log." Recent studies tend to discredit this idea 

and to emphasize the complicated nature of the components of the 

recorded self-potential. In 1942 Dickey 3 made the following statement 

regarding the relative effect of natural earth potential? on the first 

curve:

It has been demonstrated that potential differences exist naturally in the ground 

at certain points, particularly at geological discontinuities, such &^ the boundary 

between a sand and a shale stratum. It is probable that these natural differences 

of potential are always present, whether or not a well is drilled, and the sandstones 

are usually negatively charged with respect to the shales.

Little is known of the cause of these natural potentials, and tt ^ir importance 

has only recently been recognized. In most published articles on electric logging 

the potentials have been ascribed entirely to nitration and concentration pdtentials .... Recent work seems to indicate that the natural potentials existing 

in the ground, regardless of whether or not a well is drilled, are tl«; major source 

of the potentials measured in electric logging.

RESISTIVITY CURVE

The'apparent resistivity is shown on the right side of the electric 

log as one, two, or three curves, depending upon the number of different electrode spacings used. (See pi. 3.) These curves describe 

the formations penetrated by the drilled hole in terms of their resistance to the flow of an electric current. Measurable differences in 

the character of the formations in this respect are primarily dependent not upon the minerals in the formations but rather upon their 

physical characteristics and fluid content. Increases in apparent resistivity are recorded by deflections of the resistivity curves to the 

right on the electric log. Differences in the magnitude of deflection

s Dickey, P. A., Electrical well logging in the Eastern States: Pennsylvania Topog. and Qeol. Survey,. 

Progress Kept. 129, pp. 8, ft, 1942.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 165

of the three curves in the same formation are the result of differences 

in their effective penetration, which is proportional to the spacing of 

the electrodes in the hole. The electrode spacings used in the surveys for this investigation were 10 inches, 39 inches, ard 15 feet. 

Different spacings are used in other regions and by other electriclogging firms. The solid line, called the normal or "second" curve, 

expresses the resistivity recorded by two electrodes 10 inches apart. 

This accurately indicates the tops and bottoms of formations more 

than 3 or 4 feet thick by sharp deflections to the right or left. However, it does not give a true idea of the resistivity of the ratural formation because of the relatively shallow penetration of the current 

and the considerable influence of the drilling mud upon it. The 

dotted line or "third curve" registers the resistivity recorded by 

electrodes 39 inches apart. The penetration of the current with this 

spacing is somewhat greater than that of the second curve, but formational contacts are not as accurately defined. The dashed line or 

"fourth curve" is recorded by electrodes 15 feet apart. T""is spacing 

gives the greatest penetration of the formations, and, as a result, the 

most accurate recording of the resistivity of the formations and contained water. A considerable lag in the deflections marking the tops 

and bottoms of formations is always present in this curve. The 

third and fourth curves have been omitted from plate 3 for the sake 

of simplicity.

INTERPRETATION

In general it may be said that an electric log is interpreted by 

examining the form of the self-potential and resistivity curves with 

consideration of the resistivity and viscosity of the drilling mud and 

the temperature range in the hole. There is no handy rule of thumb 

for this interpretation, but the following is generally true in shallow 

fresh-water wells:

Shales and clays are indicated when both the self-potentml and re* 

sistivity are low. The almost straight self-potential curve recorded 

in shale or clay is sometimes referred to as the "shale base"; that is, 

any deviation from this line indicates a change in the porosity of the 

formation. This shale base may shift abruptly between marine and 

continental sediments but remains relatively constant in sediments of 

one origin.

Fresh-water sands are indicated by sharp deflections of the resistivity curves to the right and more moderate deflections of the selfpotential curve to either the left or right away from the shale base.

Salt-water sands are indicated by little or no deflection of the resistivity curves to the right and moderate to pronounced deflection of 

the self-potential curve to the left. Brackish water is often shown 

by the third and fourth curves recording less resistivity than the
166 CONTRIBUTIONS TO HYDROLOGY, 1944

second curve, owing to the presence of the less saline mud fluid in 

the sand adjacent to the drilled hole.

Hard dense rocks are indicated by a sharp deflection to the right of 

all three resistivity curves and little or no deflection of the selfpotential curve from the shale base.

DRILL-STEM TESTS

On the basis of information obtained from the electric log, driller's 

Tog, and sand samples, the most promising water sandr in each test 

hole were selected for further tests, known by local water-well drillers 

as "drill-stem tests." This term as generally used in petroleum exploration refers to the use of a patented testing device on the drill 

stem that allows the fluid in the formation to flow into and partly fill 

the.drill stem under natural pressure. This same device can be and 

has been used in testing some water wells but is not in common use 

by water-well drillers. Instead, many drillers place a short screen 

section on the drill stem in the sand to be tested and pump the formational water through the drill stem by air. This permits the collection of water samples and the measurement of water level, 

temperature, yield, and drawdown with a minimum of delay.

The formational tests in the test holes were made by setting 10 

feet of screen on the drill stem in the selected sand with ?n improvised 

canvas or burlap packer above the sand. A commercially manufactured packer for this type of work would have been more satisfactory but was not available. After placing the screen and packer, the 

mud cake on the sand to be tested was broken down by alternately 

washing by forcing water into the well and pumping the well by air. 

In order to retain the mud seal on the upper sands the mud column 

above the packer was disturbed as little as possible. During the 

pumping of water from the formation the level of the mud in the hole 

outside the drill stem was carefully observed to detect any failure of 

the packer to hold.

After testing the lowermost sand first, the bit was run in the hole 

and heavy mud was circulated until the sand was sealed. Then the 

screen was placed opposite the next lowest sand, and the process was 

repeated until all of the selected sands, usually four in each hole, 

were tested.

The data obtained from such tests must necessarily be used with 

discretion. The measurements of yield and drawdown in the test 

hole give little indication of the probable performance of the final 

supply well but help somewhat to show the relative water-bearing 

properties of the different sands. The water samples (fcr preliminary 

analysis only), the temperature recordings, and the static water level 

measurements are usually satisfactory and worth while.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 167 

RESULTS OF EXPLORATION

The benefits of an adequate test-drilling program prior to any large 

development of ground water are apparent from the results obtained 

in this project. The definite knowledge of the depth, character, and 

correlation of each water sand and the data on quality, temperature, 

and artesian head of the water therein make it possible to evaluate 

the potentialities of each sand in each well before any great expenditure of funds is made. These data also enable the driller and city 

officials to determine the most suitable construction method and 

pumping equipment. It is generally advisable to conduct the testdrilling program and the actual water-supply development separately 

in order to establish a basis for exact specifications which sr,ve time, 

money, and misunderstandings for both the well owner and the 

driller.

GENERAL GEOLOGY

The city of Natchitoches is located along the western edge of the 

Red River Valley on the banks of Cane River Lake, a relict meander 

of the Red River. (See fig. 54.) The Red River Valley, extending 

diagonally across Natchitoches Parish from northwest to southeast, 

has been cut into the Tertiary highlands by the Red River and partly 

filled with alluvium. The Tertiary formations exposed on the bluffs 

and underlying the flood plain are thick deposits of shallow marine, 

littoral, deltaic, and continental sediments of Eocene age about 

which only meager data are available for this locality. Considerable 

information about the paleontology and regional correlations of these 

Eocene formations has been published by Harris,4 Veatch,5 Ppooner,6 

Moody,7 Howe,8 Ellisor,9 Huner, 10 Barry and LeBlanc, 11 and others, 

but no areal geologic maps or detailed subsurface studies of the area 

between Natchitoches and Natchez have been printed.

The Eocene formations contain numerous very fine to medium 

coarse-grained water sands, which exhibit the extremely irregular 

character, thickness, and lateral extent of continental deposits.

4 Harris, Q. D., A preliminary report on the. geology of Louisiana: Louisiana Qeol. Survey report for 

1899, pp. 141-148, 1899.

* Veatch, A. C., Geology and underground water resources of northern Louisiana and southern Arkansas: 

U. S. Qeol. Survey Prof. Paper 46, 1906.

 Spooner, W. C., Interior salt domes of Louisiana: Am. Assoc. Petroleum Geologists B-ll., vol. 10, 

No. 3, pp. 217-292, 1926.

7 Moody, C. L., Tertiary history of region of Sabine Uplift, Louisiana: Am. Assoc. Petroleum Geologists 

Bull., vol. 14, No. 5, pp. 631-551, 1931.

8 Howe, H. V., Review of Tertiary stratigraphy of Louisiana: Am. Assoc. Petroleum Geologists Bull., 

vol. 17, No. 6, pp. 613-655, 1933.

« Ellisor, A. C., Correlation of the Claiborne of east Texas with the Claiborne of Louisiana: Am. Assoc. 

Petroleum Geologists Bull., vol. 13, No. 10, pp. 1335-1346, 1929.

"> Huner, J., Jr., Geology of Caldwell and Winn Parishes: Louisiana Dept. Cons. Oeol. Bufl. 15, 1939.

11 Barry, J. O., and LeBlanc, R. J., Lower Eocene faunal units of Louisiana: Louisiana Dept. Cons. Geol. 

Bull. 23,1942.
168 CONTRIBUTIONS TO HYDROLOGY, 1944

FIGURE 54. Sketch map showing topography at Natchitoches, La.

The relatively thin-bedded sands of the Wilcox formation I2 and 

the massive sands of the Sparta sand are the most important aquifers. 

South of Natchez, La., the sands in the Cockfield fornration are well 

developed and water-bearing, but only part of a section of the Cockfield formation is present within the area under consideration. The 

sands of both the Wilcox and Sparta are overlain and underlain by 

impermeable beds and yield water under artesian conditions, except 

in their respective outcrop areas. From the northwestern part of 

the city of Natchitoches southward successively younger rocks crop 

out in the hill land or underlie the flood plain in the following sequence: 

Wilcox formation; Claiborne group, including Cane Ri^er formation, 

Sparta sand, Cook Mountain formation, and Cockfield formation. 

In the Red River Valley the beveled outcrops of these formations 

are buried beneath alluvium ranging from a few feet to 104 feet in 

thickness. The possible presence of thin remnants of Pleistocene

i» The term "Wilcox formation" is used by the U. S. Geological Survey; the aarie "Sabine group" is 

preferred by the Louisiana Geological Survey.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 169

terraces on the Eocene formations at Natchitoches has not been 

investigated in this study. Table 1 gives a generalized description 

of the geologic formations and their water-bearing properties.

STRUCTURAL GEOLOGY

The Natchitoches area is structurally situated on a regie nal mono*- 

clinal flexure described by Veatch 13 in 1906 as extending froir? Angelina 

County, Tex., through Louisiana north of Natchitoches, Winnfield, 

and Columbia, to the Mississippi River north of Vicksburg. This 

regional structure developed in Tertiary time along a line of weakness 

that almost parallels the outcrop of the Wilcox formation west of 

Red River. Howe u has summarized the effect of this monocline 

on the accumulation of petroleum as follows:

The Angelina-Caldwell flexure separates northern Louisiana, with its numerous 

Cretaceous fields, from central and southern Louisiana, in which areas the oil 

production is of Tertiary age. North of this "flexure" Cretaceous formations 

lie at relatively shallow depths and are gently folded into the broad Sf.bine Uplift 

on the west and Monroe Uplift on the east. On each uplift are smaller, sharper 

folds which have served for the localization of oil and gas deposits. The depressed 

area betveen the major uplifts contains the salt domes of north Louisiana as well 

as a number of other structures on \\hich salt has not been encountered.

Southward from the Angelina-Caldwell flexure, in that portion of Louisiana 

west of the Mississippi River, the regional dip of the Tertiary formations is to 

the southeast at a rate of from 100 feet per mile to probably more tl an 200 feet 

per mile, and the Cretaceous formations are depressed under the thick accumulation of Eocene and younger sediments. The position of the Angelina-Caldwell 

flexure appears to coincide remarkably with the position of the Sabine (Wilcox) 

shoreline.

This regional monocline is complicated in the Natchitoches area 

by several faults and an abrupt change in the direction of the regional 

strike from northeast to almost due north. These local structural 

conditions are illustrated in figure 55, a structural map of the area in 

which subsurface control was adequate to contour the top of the 

Wilcox formation, and on plate 3, which shows geologic cro^s sections 

along the lines indicated in figure 53. Three major faults, one near 

Natchez and two near Natchitoches, are indicated by abrupt changes 

in formational dip, abnormal artesian conditions, and the anomalous 

presence of salt water in fresh-water sands. Vertical displacements 

of 75 to 100 feet appear to have occurred along each of the faults, 

giving rise to topographic irregularities wherever the faults are not 

buried beneath the flood-plain alluvium.

The fault near Natchez trends northeastward between well 24 in 

sec. 56, T. 8 N., R. 7 W., and the A. F. Carter Culpepper No. 1 oil

u. Veatch, A. C., op. cit., p. 315,1906.

" Howe, H. V., Louisiana petroleum stratigraphy: Louisiana Dept. Cons. Gen. Min. B 'II. No. 27, pp19, 20,1936.
170 CONTRIBUTIONS TO HYDROLOGY, 1944

 PROBABLE FAULT

O WATER WELL

0 ABANDONED TEST WELL _

FIGURE 55. Structural map of Natchitoches area contoured on top of the Wilcox formation. From maps 

of the United States Geological Survey, Campti and Bermuda quadrangljs.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 171

test in sec. 36%, T. 8 N., R. 7 W. (See fig. 55.) The apparent dip 

of the Wilcox formation between well 24 and Culpepper No. 1 is 

about 220 feet per mile, which indicates a structural break in the 

intervening area when compared to the lesser dip of 120 feet per mile 

between wells 13, 20, and 24. (See pi. 3, sec. C-C''.) As further 

evidence of this break, the upper sands of the Wilcox in Culpepper 

No. 1 contain brackish to salty water, whereas the same sands in 

wells 13, 20, and 24 contain fresh water. The formations on the 

southeast side of this fault are about 100 feet lower structurally than 

those on the northwest side. The strike of the fault cannot be 

accurately ascertained from the data available, but the abrupt 

termination of Big Henry Branch in the swamp area in sees. 34% 

and 35^2, T. 8 N., R. 7 W., suggests the direction indicated in figure 55.

Two faults near Natchitoches lie at right angles to eacl other and 

probably intersect about 2 miles southwest of the city in the vicinity 

of Old River. One of them trends southeastward from ?ibley Lake 

along Youngs Bayou, passing into a slight structural nose r,bout 1 or 2 

miles south of State Highways 1 and 6. (See fig. 55 and pi. 3, sec. 

E-E' .) The maximum vertical displacement of this fault is about 

100 feet. It forms a scarp to the west of Youngs Bayou. The 

water in the upper sands of the Wilcox to the west is fresh; that to 

the east is salty. The other fault extends northeastward from its 

probable intersection with the Youngs Bayou fault at least as far 

as Cane River Lake. This structural break, shown on plate 3, 

sections B-B' and D-D', has a vertical displacement of about 75 

feet, with the downthrown side to the northwest. Salt water is 

present in the upper sands of the Wilcox on the downtl rown side. 

The fault is obscured by flood-plain alluvium but may b°< reflected 

in the abnormal drainage pattern south of Chaplin Lake. (See 

fig. 53.) It is interesting to note the effect of this fault or barrier 

upon the artesian pressure gradient, which normally decreases away 

from the outcrop. The water level of the first sand in the Wilcox 

in well 18, on the north (downthrown) side, was about 104 feet above 

mean gulf level, while the water levels in wells 21, 22, and 23 on the 

south side were respectively, 127, 148, and 157 feet above mean gulf 

level. This shows an increase away from the nearest outcrop of the 

sand and implies that recharge is obtained laterally from the west. 

Small amounts of natural gas found in the fresh water south of the 

fault may account for part of the higher artesian pressures, but the 

relative isolation of the salt water up dip from the fresh water supports 

the idea of normal artesian conditions modified by a fault barrier.

The relative positions of the two faults suggest that the city of 

Natchitoches and the Louisiana State Normal College may be situated

827625 49 2
172 CONTRIBUTIONS TO HYDROLOGY, 1944

upon a downthrown fault block defined on the southwest by the fault 

along Youngs Bayou and on the southeast by the fault extending 

from Old River toward Cane River Lake. Unfortunately the lack of 

adequate well records prevents the definition of the northeast and 

northwest limits of this block, but the widening of the contours between wells 14 and 19 on the structural map (fig. 55) and the presence 

of brackish water in the upper sands of the Wilcox in well 19 may be 

significant. If credence can be given the drillers' logs reported for 

wells 1, 11, 14, and 16 which were drilled 3 to 30 years ago, some 

flattening of the formational dip at the city well field may be inferred. 

Necessary subsurface control farther northwest has been lost through 

the failure to preserve a log of formations penetrated in the saltwater well at the country club (well 15). In a road cut n^ar this well, 

steep dips to the southeast were noted in the sandy shales of the Wilcox 

formation. Considerably more data and detailed wort- are needed 

to outline this structure properly.

The upper sands of the Wilcox formation in this downthrown block 

contain brackish or salt water except in or near the recharge area 

where fresh water enters the outcrops. The shallow wells at relatively 

higher elevations in the northwestern part of the city are the only 

fresh-water wells on the fault block. Brine has been reported in the 

sands of the Wilcox penetrated by well 38 at Natchitoches Oil Mill 

and by other wells drilled on or near the Louisiana Sfate Normal 

College campus during the past 45 years. The uppermost sand in the 

Wilcox in well 18, near the Cane River bridge south of the city on 

State Highway 230, yielded water that contained 17,200 parts per 

million of chloride. The Louisiana State Normal College wells, about 

1 mile west of the campus, and wells 20, 21, 22, 24, 25, 28, and 29, 1 

to 5 miles south of Natchitoches, are located beyond the faults limiting the west and south sides of the downthrown block and consequently 

yield fresh water.

The origin of this fault block may be associated with the origin of 

the topographic feature known as Sibley Lake, west of the city. 

This sb-called lake is in reality a swamp drained only by Youngs 

Bayou to the south, along which a fault is indicated. This swamp 

is almost completely circled by hills (see fig. 54), receiving runoff from 

the upper end of Youngs Bayou on the west, Rio Hondo on the northwest, several unnamed streams on the north, and Bayou Jacko 

on the east. As shown in figure 54, a sketch map of the topography 

of this area, the surface of the swamp is less than 100 feet above mean 

gulf level. This indicates that subsidence similar to the central 

collapse over salt domes, described by Spooner,15 may be responsible 

for both Sibley Lake and the downthrown fault block at Natchitoches.

>» Spooner, W. C., op. cit., pp. 223-224.
GROUND-WATER EXPLORATION, NATCHITOCHES ABEA, LA. 173

The existence of a salt dome in this area cannot be proved from the 

available data, but the fact that the salt water from the first sand in 

the Wilcox in well 18 is not similar in chemical composition to connate 

sea water but resembles a soft sodium-bicarbonate water mixed with 

salt-dome brine 16 lends support to the theory. Veatch " in 1906 expressed the belief that subsurface leakage of brine fron known salt 

domes far to the north had contaminated the ground water at Natchitoches. In view of the new data at hand, this long-distance migration 

of brine seems very doubtful. Wells dug 12 to 16 feet deep into the 

outcrop of the uppermost sand of the Wilcox in the Bayou Jacko 

lowlands west of the city are known to yield brackish o^ salty water. 

(See table 3, well 39.) Geophysical investigations by commercial 

operators may already have proved or disproved the existence of 

salt-dome structure at Natchitoches, but the results of such investigations have not been available to the writers.

QUALITY OF WATER

The chemical character of the water from the format; ons cropping 

out in this area is discussed further in this report in the section on 

Geologic formations and their water-bearing properties.

Thirty-nine samples of water from 9 wells and 10 test holes, representing the character of the water in each water sand at different 

localities, were collected and analyzed in the water resources laboratories of the Geological Survey at Austin, Tex., and Washington, 

B.C. The analysts were M. D. Foster, L. W. Miller, W. W. Hastings, 

and J. H. Rowley. The results of this analytical work are shown in 

table 4. The method of obtaining drill-stem samples in the test holes 

is described in the section on Drill-stem tests.

In general the natural waters from the sands of the Wilcox and 

Sparta formations are of the soft sodium-bicarbonate type, gradually 

increasing in mineralization down dip until they resemble sea water 

in composition. However, the local effect of faulting, associated 

with the probable structural deformation west of Natchitoches, is 

to create anomalies in the normal change in chemical character of 

the waters. This is illustrated by the water from the first sand of 

the Wilcox in well 18 at the south edge of the city. This water, 

fresh in wells up dip to the north, along the strike to the west, and 

down dip to the south, contains 17,200 parts per million of chloride. 

Its composition resembles that of a soft sodium-bicarbonate water 

contaminated by salt-dome brine rather than that of s°-a water, 18 as 

would be expected under normal conditions.

i« Foster, M. D., personal communication.

» Veatch, A. C., op. cit., p. 78.

" Foster, M. D., personal communication.
174 CONTRIBUTIONS TO HYDROLOGY, 1944

At localities where the waters in the sands of the Wilcox and Sparta 

are fresh, they usually contain large amounts of bicarbonate and have 

moderately large total dissolved solids. Aside from the fact that 

objectionable amounts of iron are somewhat more common in the 

waters of the Wilcox, the waters from the two aquifers are about 

equally satisfactory for human consumption. The iron content of 

the waters from the Wilcox formation ranges from 0.02 to 12 parts per 

million; that of waters from the Sparta sand ranges from 0.08 to 5.4 

parts per million. Fluoride slightly in excess of 1 part per million 

was found in one sample from the Sparta sand.

The water from the Recent alluvium in the flood plain is hard and 

generally contains objectionable amounts of iron. Tve chloride 

content was not found to be excessive in any of the samples tested. 

However, the water from the Recent alluvium is not satisfactory for 

public supply without treatment. Where the sands of the Wilcox 

and Sparta directly underlie the Recent alluvium there re ay be either 

upward or downward leakage between the sands, depending upon the 

respective pressures in the sands, and the chemical character of the 

waters at such places may represent a mixture.

GEOLOGIC FORMATIONS AND THEIR WATER-BEARING

PROPERTIES

E In the following discussion, beginning with the Wilcox formation, 

the geological formations underlying this area are listed in the order 

in which they were deposited and in which they crop out from north 

to south. The wells referred to are described in table 2, and their 

locations are shown by number in figure 53. Analyses of water from 

most of these wells are given in table 3. The texture of the water 

sands is shown by the mechanical analyses in table 5.

EOCENE SERIES 

WTLCOX FORMATION

The sediments of the Wilcox formation lfl crop out in a relatively 

wide belt extending from southwestern Sabine Parish northeastward 

to the Red River near Natchitoches and thence northward into 

"Arkansas. These sediments, representing alternating marine and 

nonmarine deposition near the strand line in Wilcox tiire, are composed principally of dark finely laminated, micaceous sands and clays 

of irregular character, thickness, and distribution. The s°,nds, which 

predominate in the section, are generally laminated or cross-bedded in 

structure with only a few that appear on the outcrop to be massive. 

Most of the sands are fine-grained although coarse-grained phases are 

present at a few places. The clays and shales range from buff to

14 Referred to as Sabine group by the Louisiana Geological Survey.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 175

black in color and contain considerable lignitic material and some 

layers of marine shells and glauconite. Concentrations of pyrite 

nodules large enough to be logged as rock have been found in water 

wells penetrating the Wilcox sediments, and sandy limestone is not 

uncommon.

According to Spooner w the Wilcox sediments range in thickness 

from 800 feet in northern Louisiana to more than 2,500 feet in this 

area. However, in some recent publications 21 the lower part of this 

section is now considered to be of Midway age. As water wells in 

the Natchitoches area penetrate only a few hundred feet of Wilcox 

sediments, the discussion of this problem is not pertinent in this 

report.

Fresh water is found at Natchitoches in three sands in the upper 

200 feet of the Wilcox formation. These sands are irregular in 

character and thickness, grading partly into sandy shale and shale 

at some locations. The upper sand marks the transitior from the 

arenaceous continental deposits of the Wilcox formation to the marine 

clay and marl of the Cane River formation of the Claiborne group. 

Uncomformable relations reported to exist between the Wilcox 

formation and the Claiborne group were not apparent in this area. 

The upper sand crops out north and west of Natchitoches, forming 

gray sandy soil. There are numerous exposures along State Highway 

6 west to Hagewood and a particularly good one in a road cut about 

half a mile south of Hagewood on State Highway 39. In general the 

sand is fine to medium-coarse in texture with considerable crossbedding and includes many clay pebbles. It is almost alvays micaceous, and the basal portion generally contains large amounts of 

glauconite and shell fragments. In water wells and test holes the 

thickness of the upper sand ranged from 26 to 50 feet, the maximum 

thickness being in well 17 where the sand lies near the land surface; 

in other wells the average thickness was about 40 feet. Some of the 

differences in thickness from well to well are caused by the upper part 

of the sand lensing into sandy clay or shale, as in well 21. (See pi. 3, 

sec. C-C1'.) Mechanical analyses (see table 5) show that this sand is 

the coarsest sand of the Wilcox, and the geologic cross sections indicate 

that it is the most uniform in thickness.

The second sand of the Wilcox formation is very irregular in 

character and contains many hard rock layers and clay lenses. Its 

thickness ranges from 9 to 45 feet, increasing down dip. Tie texture 

is fine and the permeability low. Usually 20 to 40 feet of clay and 

rock separate it from the upper sand.

20 Spooner, W. C., op. cit., p. 234.

21 LeBlanc, R. J., and Barry, J. O., Fossiliferous localities of Midway group in Louisiana: Am. Assoc. 

Petroleum Geologists Bull., vol. 25, pp. 734-737,1941. Murray, G. E., Midway microfauna of northwestern 

Louisiana: Am. Assoc. Petroleum Geologists Bull., vol. 25, pp. 738-742, 1941.
176 CONTRIBUTIONS TO HYDROLOGY, 1944

The third sand of the Wilcox formation appears about 30 feet below 

the second, and its thickness, which is even more irregular than that 

of the second sand, ranges from only a few feet to 37 feet. Down dip 

it grades into fine sand with intercalated clay and layers of rock. 

This sand is relatively unimportant as an aquifer in the Natchitoches 

area.

The sands of the Wilcox formation are so fine-graired near the 

outcrop that most wells so located must be screened in two sands to 

produce small to moderate quantities of water. Wells 1 to 12 at the 

city water plant in northwestern Natchitoches draw upon the first 

and second sands, yielding an average of 30 gallons a mirute per well. 

Salt water is found below the second sand. The wells are closely 

spaced and the sands are fine, resulting in overpumping in that area. 

At the Louisiana State Normal College well field, wells 30 to 37 are 

screened in the second and third sands, which are better developed at 

this locality. Here, too, close spacing combined with the fine texture 

of the sands has caused some difficulty. The yields of these wells are 

not accurately known but are about the same as those of the city 

wells. The college wells are situated west of a fault exte-nding southeastward along Youngs Bayou. This probably accounts for the 

presence of salt water in the same sands only a mile or so east, at the 

college proper.

Test holes drilled into the sands of the Wilcox formation where they 

underlie the flood plain show that these sands have sufficient pressure 

for the water to flow at the surface at all locations south of well 18. 

Well 18, apparently located on the downthrown side of a fault (see 

pi. 3, sec. B-B'}, has an abnormally low water level of 104 feet above 

mean gulf level (8 feet below the land surface). The remainder of the 

tests in the flood plain recorded water levels in the sands of the Wilcox 

ranging from about 115 to 157 feet above mean gulf level (4% to 58 

feet above land surface). Quantities of gas present in some of the 

tests may be partly responsible for some of the higher artesian pressures recorded. The yields of the test wells ranged from 5 gallons 

a minute in well 20 to 30 gallons a minute in well 25. However, 30 

feet of screen was set in well 25 as compared with only ] 0 feet in the 

others.

Salt water was recorded in the sands of the Wilcox formation in 

wells 18, 26, 27, 38, and the A. F. Carter Culpepper No. 1. The 

salt water in wells 18 and 38 is probably a result of contamination 

by salt-dome brine. This contamination is probably related to two 

faults (see pi. 3, sees. B-B' and D-D'), one trending northeastsouthwest between wells 18 and 21, and the other northwest-southeast, separating the college well field from wells 18 and 38. A sample 

from well 18 tested 17,200 parts per million of chloride and, accord-
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 177

ing to M. D. Foster of the Water Resources Branch Laboratory, 

resembled a soft sodium-bicarbonate water mixed with brir^ from a 

salt dome. The salt water recorded in the Culpepper oil test is also 

associated with faulting. (See pi. 3, sec. C-Cr .) Where geologic 

conditions are normal and the waters fresh, both the harcfness and 

the chloride content of the waters range from about 5 to 100 parts 

per million. The waters contain variable amounts of iron, ranging 

from 0.05 to 12 parts per million. The bicarbonate content usually 

exceeds 400 parts per .million.

CLAIBORNE GROUP

CAKE RIVER FORMATION

The Cane River formation, the basal marine formation of the 

Claiborne group which directly overlies the Wilcox formation, is 

named for the excellent exposures of marine clays and marls along 

the west bank of Cane River Lake at Natchitoches. It? outcrop 

parallels that of the sandy Wilcox formation to the west and north, 

forming flat-land topography in contrast to the irregular hills of the 

Wilcox and Sparta. The upper part of the Cane River formation is 

composed principally of dark glauconitic sandy clay and shale with 

abundant microfossils. The lower part consists of fossililerous glauconitic sandy shale and marl. A soft limestone about 6 feet thick 

occurs about 40 feet above the base of the formation. THs 6-foot 

limestone bed is a key marker horizon, as it is easily identified on the 

electric logs and drillers' logs. In the Natchitoches area the Cane 

River formation ranges from 106 to 135 feet in thickness, thickening 

down the dip as shown on plate 3, sections B-B' and C-C'. In this 

area there are no productive water-bearing sands in the Csne River 

formation, and the little water that does occur in the sandy shales is 

highly mineralized.

SPARTA SAND

Beds of light-colored sand-and sandy clay with some lignitic material and only a very few scattered fossils overlie the Cane River 

formation. These beds are known collectively as the Sparta sand, 

which was recognized by Spooner w as extending from th^ lowest 

fossiliferous horizon of the Cook Mountain formation to the marine 

clays of the Cane River formation. Spooner's description of the 

Sparta sand as given below applies very well to the formation in the 

Natchitoches area, except that the thickness here does not exceed 

300 feet.

The lower half of the Sparta sand is made up chiefly of massive sand with 

interbedded subordinate members of laminated sandy clay. The massive sandsare made up of quartz grains somewhat coarser than found in the Wilcox forma-

" Spooner, W. C., op. cit., p. 236,1926.
178 CONTRIBUTIONS TO HYDROLOGY, 1944

tion. The upper half contains a relatively greater amount of clay than the lower 

hah8 . Massive sands alternate with beds of finely laminated sandy clay, in part 

lignjtic and in many places containing fossil leaves. The upper 50 feet of beds 

contain a considerable amount of lignitic material and some thin lignitic beds 

which are particularly well exposed in the vicinity of the town of Bienville. The 

beds are commonly light colored, but, depending upon the amount of iron and 

carbonaceous matter, red and brown-colored beds occur. Fossils are generally 

absent from the Sparta sand, but a few species of near-shore forms are found 

near the middle of the formation. The Sparta sand has a thickness of 400 to 

500 feet, with the greater thickness in the northern part of the salt-dome region

Massive sands of the Sparta crop out south and southwest of the 

city of Natchitoches and form the belt of sandy hills that lies south 

and southeast of Bayou Souris. The northeast trend of these sandy 

ridges is interrupted by the Red River Valley where the Sparta sand 

is buried beneath Recent alluvium. *

Previous to the test drilling by the city of Natchitoches the Sparta 

sand had never been developed in any water wells in this vicinity. 

This is surprising in view of the poor quality of the water from the 

Recent alluvium, in which many farm wells have been finished, and 

the relatively shallow depth to the Sparta sand in most of the area. 

Seven of the nine test wells drilled by the city tested the Sparta sand, 

five of them (wells 22, 23, 24, 25, and 28) penetrating complete sections of the Sparta. One other well, the oil test, A. F. Carter Culpepper No. 1, in sec. 36^, T. 8 N., R. 7 W., also drilled through a 

complete section of the Sparta sand. On the basis of these drillings 

the total thickness of the Sparta sand ranges from 260 to 283 feet, 

thickening down dip to the south. The percentage of sand in the 

section also increases down dip, being less than 20 percent in well 25 

and more than 80 percent in the A. F. Carter Culpepper No. 1. The 

sands are generally fine to medium coarse-grained, the f ner material 

predominating. (See table 5.) Despite the irregular and unpredictable character of the sand bodies, the principal water sands are probably interconnected, as the water levels recorded in drill-stem tests 

at different sand horizons in the Sparta agree very well. Drill-stem 

tests of the Sparta sand were made in six of the test holes. The water 

levels ranged from 101 feet above mean gulf level (8 feet below land 

surface) in well 21, to 127 feet above mean gulf level (SO feet below 

land surface) in well 24. Intermediate artesian heads are present 

between these wells, showing a pressure gradient 'eastward. This is 

in accord with geologic evidence pointing to recharge of the water 

sands in the hill lands west of the flood plain. The yields obtained 

in the drill-stem tests ranged from 5 to 48 gallons a minute, the highest yield being from well 24. These yields are valuable only for comparative purposes and do not represent the probable yields of supply 

wells in the formation tested. Fresh water was found in all of the
GROUND-WATER EXPLORATION, NATCHITOgHES ARE^. LA. 179

drill-stem tests except those in well 23, the southeastemmost test 

well. The water from this well was slightly brackish; the sample from 

the upper part of the Sparta sand tested 559 parts per million of 

chloride and the one from the lower part of the Sparta sand, 341 parts 

per million. This limits the area in which fresh water may be found 

.in the Sparta sand beneath the flood plain to the land south of wells 

20 and 21 and northwest of well 23. In the hill land the Sparta sand 

contains fresh water as far south as Flora and probably as far west 

as the Texas line.

The fresh water from the Sparta sand is generally soft and alkaline. 

In the nine samples analyzed (see table 3) the hardness ranged from 

4 to 114 parts per million and averaged 33.5 parts per million. The 

maximum figure, 114 parts per million, was recorded for a sample from 

well 21, where the beveled edge of the Sparta sand is directly overlain 

by Recent alluvium containing hard water. It is thought that the 

sample of water from supposed Sparta sand in well 21 was a mixture 

of waters from the Sparta sand and the Recent alluvium. This conclusion is borne out by the relatively high iron content of the sample, 

1.1 parts per million. The bicarbonate content of the samples averaged 

317 parts per million. None of the samples contained fluoride in 

excess of 1 part per million.

COOK MOUNTAIN FORMATION

The Cook Mountain formation is comprised of fossiliferous marine 

sands and clays lying between the nonmarine sandy sediments of the 

Cockfield formation and Sparta sand. The sands are generally finegrained and very irregular in character, usually containing numerous 

hard layers of ferruginous sandstone. The color of the sands ranges 

from light gray to brown and red. The clays are of mar.y different 

colors, depending upon the amounts of iron, carbonaceous material, 

and glauconite present. Nodular limestone horizons and marl beds 

occur in the lower part of the formation, and both the uppermost and 

lowermost beds are extremely fossiliferous. The thickness of the formation in the Natchitoches area ranges from 224 to 244 feet. Owing 

to its relative impermeability this formation cannot be considered as 

a possible source of water supply at Natchitoches.

In the course of the field work in the outcrop area of the Cbok Moun,- 

tain formation south of Natchitoches an interesting vertebrate fossil 

was found by the junior author in the lower part of the section (Huner's 

Milams member of the Cook Mountain formation) 23 which is exposed 

at the edge of the hills adjacent to the flood plain in sec. 10, T. 8 N., 

R. 7 W., about 100 feet north of well 28. The fossil material was

23 Huner, J., Geology of Caldwell and Winn Parishes: Louisiana Dopt. Cons. Geol. Pull. No. 15, pp, 

91, 95,1939.
180 CONTRIBUTIONS TO HYDROLOGY, 1944

<x)llected and sent to J. B. Reeside, Jr., of the Geological Survey in 

Washington, D. C., who referred the material to Remington Kellogg 

of the United States National Museum. The following if a quotation 

from a letter from Reeside regarding the identity of the specimen:

Remington Kellogg, of the U. S. National Museum, reports that the specimen 

from the Cook Mountain formation in Natchitoches Parish is an entirely new 

Archaeocete (the toothed whales formerly known as Zeuglodonts). It still lacks 

a name and, being new, gives little help in correlation. The occurrence is the 

 earliest recorded for this group of animals in the Gulf region.

H. V. Howe, of Louisiana State University, identified the following 

list of microfossils from the clay matrix of the specimen and confirmed 

the field identification of the matrix as marl from the Milams member 

of the Cook Mountain formation.

FORAMINIFERA

Siphonina claibornensis 

£iphonina goochi 

Siphoninella claibornensis 

Gyroidina soldanii octocamerata 

Eponides guayabalensis 

Anomalina costiana

 Anomalina umbonata

 Ceratobulimina eximia 

Planulina kniffeni

 Cibicides pseudowuellerstorfi

 Cibicides lawi 

Cibicides sassei 

Cibicides mauricensis 

Asterigerina hadleyi 

Globorotalia centralis 

Globorotalia crassata 

Globorotalia spinulosa 

Globigerina topilensis 

Globigerina auachiiaensis

 Globogerina mexicana 

Textularia zapotensis 

JZarreriella mauricensis 

Robulus alate-limbatus 

Robulus pseudocultratus 

Robulus jugosus 

Lagena mauricensis

Cythereis cooleycreekensis 

Cythereis winniana 

Cythereis undosa

 Cytheridea montgomeryensis 

Cyiheridea oliveri

Lagena ouachitaensis 

Guttulina austriaca 

Gullulina irregularis 

Globulina minuta 

Globulina gibba 

Nonien florienensis 

Nonion planatum 

Nonion micrum 

Nonionella mauricensis 

Discocyclina perpusilla 

Triloculina garretti 

Triloculina trigonula 

Triloculina mindenensis 

Triloculina natchitochensis 

Uvigerina blanca-costata 

Loxostomum claibornense 

Bulimina robertsi 

Quinqueloculina mauricersis 

Maasilina mauricensis 

Operculinoides sabinensis 

Cornuspira olygogyra 

Glandulina laevigata 

Kobulus mexicanus 

Dentalina winniana 

Discorbisf globulospinosa

OSTRACODA

Cytheropteron proboscense 

Loxoconcha claibornensis 

Loxoconcha. -chaanfera 

Brachycythere russelli 

Brachycythere watervalleyinsis
GROUND-WATER EXPLORATION, NATCHITOCHES ARE;?, LA. 181 

COCKFIEID FORMATION

The Cockfield formation is exposed at the surface in the southern 

part of the Natchitoches area west of Natchez. It consists of fine 

light-colored sands, generally massive in structure, with laminated, 

thin-bedded sandy clays and lignitic silty shales. Although no marine 

fossils are reported in the formation, numerous horizors of fossil 

leaves and concretionary zones do exist. The entire section has not 

been penetrated by wells in this area, but it is reported to exceed 500 

feet in thickness in oil tests in adjacent areas. The only well cited in 

this report that penetrated the Cockfield formation is the A. F. Carter 

Culpepper No. 1, which is located on the downthrown side of a fault. 

{See fig. 55.) This oil test drilled through 163 feet of the Cockfield, 

beginning at the land surface.

The Cockfield formation yields fresh water to wells several miles 

farther south. At Flora wells ranging from 300 to 350 feet in depth 

'draw upon this source. Because of the low permeability of the water 

sands the yields of these wells are not large. The water is reported 

to be moderately soft to moderately hard, 50 to 120 parts p?r million, 

and to contain rather large amounts of bicarbonate and sulfate.

PLEISTOCENE AND RECENT SERIES

Sand, gravel, and clay of Pleistocene and Recent age mantle the 

 older formations in central Louisiana. The Pleistocene deposits have 

'been described by Fisk 24 as four formations, Prairie, Montgomery, 

Bentley, and Williana, which form four terraces above the present 

Red River flood plain. Huner 25 mapped these terraces in nearby 

Winn Parish, but such work has not been done in Natchitoches Parish. 

Remnants of these terraces may exist in the hills in the Natchitoches 

area under consideration, but they are too thin and scattered to warrant consideration as aquifers. The flood plain along Cane River 

Lake is underlain by Recent alluvium ranging in thickness from a 

few feet to about 104 feet. This alluvium grades downward from 

clay into coarse sand and gravel. The upper red-colored clay is 25 to 

35 feet thick and overlies bodies of fine sand and sandy clay, which 

extend to a depth of about 50 to 60 feet. The coarse material is generally below a depth of 60 feet. Gravel is not present at all locations, 

although the sand is generally coarse enough to yield moderately large 

supplies of water.

The water level in the Recent alluvium ranges from 9 to 17 feet below 

the land surface. Yields of 3 to 25 gallons a minute were obtained in 

drill-stem tests of this alluvium. The temperature of the water is

84 Fisk, H. N., Geology of Avoyelles and Rapides Parishes: Louisiana Dept. Cons. Oeol. Bull. 18, p. 

175, 1940. 

>s Huner, J., Jr.. op. cit., pp. 46-55.
182 COJSTRIBU-HQiiS TO

about 67° F. All of the water is hard, the hardness ranging from 342 

to 510 parts per million, and the iron content usually exceeds 3 parts 

per million. (See table 3.) This water is not suitable for most domestic purposes without treatment.

SUMMARY AND CONCLUSIONS

In the area between Natchitoches and Natchez (upper half of 

T. 8 N., R. 7 W., and all of T. 9 N., R. 7 W.) the geologic formations 

that will yield a water supply of at least 1,000,000 gallons a day are 

the upper sands of the Wilcox formation, the Sparta sand and the 

Cockfield formation of the Claiborne group, and the Recent alluvium. 

Water from the Recent alluvium is the most accessible, ae wells located 

just east of Cane River Lake would supply the desired quantity. 

However, this water is not satisfactory for public supply without 

treatment, as it js very hard and contains objectionable amounts of 

iron. The water from the Cockfield formation is generally moderately 

soft to moderately hard and is well suited for domestic or industrial use, 

but the formation is present only in the extreme southern part of the 

area. The distance involved in piping water to the city from wells in 

this formation prohibits consideration of it as a possible source of 

water for the public supply of Natchitoches.

1 The upper sands of the Wilcox formation which underlie Natchitoches supply small amounts of fresh water to municipal wells in the 

north part of the city and to the wells of the Louisiana State Normal 

College southwest of the city. Between the two well fields the sands of 

the Wilcox contain salt water, the occurrence of which is probably 

associated with structural deformation in the Sibley Lake area. The 

water-bearing sands have been overdeveloped at both well fields, and it 

would be inadvisable to drill additional wells at either place. The site 

for a new well field, therefore, must be south of the city, beyond the 

areas of faulting and salt-water contamination, as described in the 

section on structural geology.

Test wells 20 and 21 revealed that the upper sands of the Wilcox 

formation at these locations contain fresh water but are too thin and 

fine-grained to warrant the installation of supply wells. The proximity of faulting and the unfavorable location with respect to the area 

of recharge further impair their possibilities. Test well 22 recorded 

sands of the Wilcox of favorable thickness and texture, but the danger 

of salt-water intrusion renders this location undesirable. The chloride 

content of waters from the Wilcox formation in well 22 is 95 to 103 

parts per million, but in well 23, 1% miles south, these waters are 

salty. (See pi. 3, sec. B-B'.} Heavy pumpage in the vicinity of well 22 

might cause the salt water to encroach upon the pumped wells. The
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 183

locations of test wells 24, 25, and 28 appear to be satisfactory for 

supply wells in the Wilcox formation.

The Sparta sand does not underlie Natchitoches and the immediate 

vicinity, but the beveled edge of the formation was penetrated by 

both wells 20 and 21, located about 1% miles south of Natchitoches. 

(See pi. 3, sees. B-B' and C-C'.} Water sands of the Sparta tested in 

wells 20, 21, and 23 are not considered worthy of development, because 

they either contain highly mineralized water or are too thin and finegrained. West of the valley the sands of the Sparta are thicker and 

more permeable, the water levels are higher, and the quality of the 

water is good. Test wells 24 and 28 revealed sands in tl o Sparta 

that are suitable for development in supply wells.

It is thought that four or five properly developed wellr drawing 

upon the sands of the Wilcox formation and the Sparta sard in sees. 

10, 56, and 57, T. 8 N., R. 7 W., will supply as much as 1,000,000 

gallons of water a day. The most feasible distribution, of these wells, 

if the pipe line is laid along the highway right-of-way, is either a T-- 

shaped or straight-line pattern, with the wells at approximately 

half-mile internals .to minimize the pumping interference between 

wells drawing upon the same sand. In either case the first two well 

locations would be the same, that is, supply well 1, screened in the 

first sand of the Wilcox, at the Old River bridge on State Highway 

432 and supply well 2, screened in the Sparta sand, at the location of 

test well 28 half a mile southwest of well 1 on State Highway 432.

In following the T pattern, supply well 3 would be drilled about 

half a mile north of well 2, and well 4, half a mile south of well 2. 

If a fifth well is needed it is possible that a double location could be 

made at one oi the previously drilled sites where sands of both the 

Wilcox and Sparta appear favorable. This T pattern would place all 

of the wells on the flood plain and result in a minimum of drilling 

footage. Probably all of the wells would flow at the surface to a small 

extent, but that is not significant, because the total pumping lift 

necessary to bring the water to the land surface and pump it through 

the pipe line into the city would be about the same whether the wells 

are on the lowland or in the hills.

In following the straight-line pattern, the pipe line would be 

extended into the hills along State Highway 432 toward test well 24. 

Supply wells 3 and 4 would be situated at approximately half-mile 

intervals southwest of supply well 2. It is likely that two wells, one 

in the Sparta sand and one in the first sand of Wilcox formation, 

might be feasible at the location of well 3 or well 4. This pattern of 

wells requires deeper wells than the other pattern but ofers some 

offsetting advantages. The sands of the Sparta appear to 1 °- thicker
184 CONTRIBUTIONS TO HYDROLOGY, 1944

and coarser in the hill land than in the valley, and therefore larger 

yields ma/ be expected from wells tapping this formation in the hills. 

The wells in the hills may be located adjacent to the highway, whereas 

supply wells 3 and 4 in the lowland would require the cor struction and 

maintenance of side roads.

Regardless of the plan decided upon, it will be advisable to drill 

pilot holes at the locations before the large-diameter holes are drilled. 

The supply wells should be equipped with meters and air-line gages,, 

so that accurate records of pumpage and water levels m<»y be kept.

The results of this investigation are of regional value when it is 

recalled that the water sands of the Sparta and Wilcox extend westward into Texas and northward into Arkansas. A fevr large water 

supplies, principally for paper mills, have been developed from the 

Sparta sand north and east of the Red River, but no large developments have been made in Louisiana west of the Red Rive1-. The establishment of new industrial plants requiring moderately large supplies 

of soft water is feasible in west-central Louisiana immediately south 

of the outcrop of the Sparta sand. The irregular character of this 

formation does not permit accurate estimates of the yields to beexpected in wells, so the selection of favorable' sites for ground-water 

supplies will require additional exploratory drilling. As it may be 

desirable for the city of Natchitoches to extend its proposed well field 

to the west in case of increased consumption in the future, it will not 

be advisable to develop another large ground-water supply withm< 

several miles of the proposed city well field.
TABLE 1. Outline of stratigraphy in Natchitoche

System

Quaternary.

TertiarySeries

Recent.

Pleistocene.

Eocene.

Formation

Claiborne group.

Cockfleld formation.

Cook Mountain formation.

Sparta sand.

Cane River formation.

Wilcox formation.

Approximate 

total thickness (feet)'

0-104

?

500 (?)»

224-244

260-283

106-135

2,600 (?)»

Character of r

Silt, clay, sand, and gravel, 

valleys.

Clay, sand, and gravel as ter

valleys.

Massive irregular/ light-co

thin-bedded saady clays 

with marine fossils.

Varicolored glauponitic a

clays, cross-bedcted ferrugi

ferous marl, and ironston

Massive irregular saads 

sandy clay.

Chocolate brown clays, glau

sandy shales with marin

Dark finely laminated sand

considerable lignite.

1 Total thickness of complete section in wells in this area.

' Cockfleld formation reported to exceed 600 feet in thickness.

' IVtlcox formation, including lower section now assigned to Midway group by Louisiana Geological Survey
TABLE 2. Records of wells in the Natchitoches 

[PS, Public supply; Ab, abandoned; T, test; D, domestic; S, stock. Numbers designating the wells are the 

maps of U. S. Geological Survey or aneroid trave

No.

l(Na-ll)..- 

2(Na-12).__ 

3(Na-13)._. 

4(Na-16) . 

5(Na-17).- 

6(Na-15)__. 

7(Na-18)___ 

8(Na-19).__

9(Na-20)--

10 (Na-21)-_

11 (Na-52)__

Location

S. cor. power plant, in 

irreg. sec. 45, T. 9 N., 

R. 7 W., Natchitoches. 

SW. side power plant in 

irreg. sec. 45, T. 9 N., 

R'. 7 W., Natchitoches. 

W. cor. power plant, 

in irreg. sec. 45, T. 9 

N., R. 7 W., Natchitoches. 

NW. side power plant, 

in irreg. sec. 45, T. 9 

N., R. 7 W., Natchitoches. 

N. cor. power plant in 

irreg. sec. 45, T. 9 N., 

R. 7 W., Natchitoches. 

W/cor. plant property 

in irreg. sec. 45, T. 9 

N., R. 7 W., Natchitoches. 

Across road NW. of 

power plant, irreg. sec. 

44, T. UN., A. 1 W., 

Natchitoches. 

.....do.................

.....do. ................

.....do.................

N. cor. plant property 

in irreg. sec. 45j T. 9 

N., R. 7 W., Natchitoches.

Owner

City of Natchitoches.

... ..do. __.'____ ..

.....do.. ......

.....do..........

.....do.. .._.._._

.....do.. .....

.....do...........

.... .do. .........

... ..do. ........ .

.....do.-.. .......

..... do. .........

Date completed

July 1913......

.....do........

 June 1941.....

Diameter (inches)

8 

6 

6 

8 

8 

6 

8

8 

8 

8 

6

Total depth (feet)

102 

80 

90 

90 

85 

60 

65

190 

190 

200 

255

Aquifer (depth 

in feet)

Wilcox (18-62). 

Wilcox.. .

.....do.. ......

.....do........

.....do........

...-.do.-....-.

. .do...... .

.....do........

.....do........

.....do. .......

Wilcox (40-61) 

(146-160)

Screen 

setting 

(depth 

in feet)

20-60 

15-55

39-70 

135-156
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, "LA. 187

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188 CONTRIBUTIONS TO HYDROLOGY, 1944

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GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 189

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TABLE 3. Partial analyses of water samples from well

[Analyses by M. D. Foster, L. W. Miller, W. W. Hastings, and J. H. Rowley. Parts per million except 

Well No.

1 rWn-lIt

9 (Na-20) . - - . 

10 (Na-21) _ ....... ...........

11 (Na 52)............... ...

11 (Na-52)_ ... 

13 (Na 52)....... ...........

17 (Na-49). . ...-.. -

1 7 fXTn 4Q1

18 (Na-50). ..-.-.........

18 (Na-50)- 

19 (Na-51). ....................

20 (Na-53). ........... ......

21 (Na-54)- .. .. - .-

21 (Na-54). ....--. ............

21 (Na-54) ...... ..... .

21 (Na-54). .......-....-....

22 (Na-56). 

22 (Na 56). 

22 (Na-56)-.-........-.. .

23 (Na-57). ....................

23 (Na-57).. ................

23 (Na-57)..-.......--..-......

23 (Na-57) 

24 (Na-55)- 

24 (Na-55) 

24 (Na-55) 

24 (Na-55) 

25 (Na-58) ... ... -....

25 (Na-58)- 

25 (Na-58)... .. . -..

25 (Na-581 .. ... 

25 (Na-58).. . -.

25 (Na-61). .. . . . .

28 (Na-61) 

29 (Na-27)- .. - --

36 (Na-25)... ..... ... _ ....

37 (Na-26) .. 

39 (Na-66)... 

Depth of 

screen 

(feet)

80

190

200

f 61

L 160 

254

f 116

I 186 

208

484

85

282

93

228

105

160

380

427

95

413

694

680

361

594

764

846

382

445

604

682

90

145

269

Wn

672

250

550

550

262

182

12

Geologic 

formation

W

W

W

} W

W

} W

W

W

R

W

R

W

R

S

W

W

R

S

W

W

S

S

W

W

S

S

W

W

R

S

S

W

W

S

W

W

W

W

W

Iron (Fe)

12

3.4

.09

4.2

1.1

.61

.29

3.4

.56

6.0

2.3

5.4

.72

.13

4.2

.34

.10

.05

11

5.1

.14

.08

.06

.10

.52

.02

.07

Calcium 

(Ca)

26

5.7

2.6

76

24

2.2

2.0

92

2.5

4.0

3.4

7.7

3.7

49

48

17

9.6

3.4

3.4

18

5.1

1.3

9.5

3.8

7.1

3.4

9.1

Magnesium 

(Mg)

13

3.9

1.3

37

13

1.4

.8

52

1.3

1.4

1.4

2.7

.6

22

22

3.2

1.4

.7

1.5

39

2.1

.2

.6

1.6

1.3

1.0

2.6

Sodium 

and Potassium 

(N+E)

33

25.5

221

191

367

272

305

199

129

321

295

512

321

2,640

2,900

90

93

275

236

85

293

110

297

527

149

296

58.6

Bicarbonate 

(HCOs)

4

30

33

174

490

178

73

1,202

784

460

484

574

708

689

646

672

768

298

676

626

360

262

555

529

208

192

656

608

401

464

199

679

774

184

678

577

164

186

351

Su

(S

40

i Later field tests after continued pumping indicated chloride content increased to about 550 parts per mil
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 191

TABLE 4. Logs of welts in the Natchitoches area, Louisiana

[Records of wells are included in table 2, and locations are shown in fig. 53. Data from drillers' logs, electric

logs, and samples]

Well 1 (Na-11)

Eocene series:

Wilcox formation: Depth (feet) 

Red and yellow clay.____________________________________ 0-18

Fine sand____________.._._..._.________..___.. .._ 18-62

Black sand (?) and lignite.-------_.___.____.___.-_..__. 62-128

Well 11 (Na-52)

Eocene series:

Wilcox formation: Depth (feet) 

Soil and clay,____-______________-____--_____-_--_-_----- 0-3

Medium-grained yellow sand__._______________-_-_-_-__--_ 3-15

Ferruginous yellow sandy clay. ___________________________ 15-24

Medium-grained yellow sand_________________________-__ 24-40

Medium-grained gray sand.__._.__...________.___.__-____ 40-61

Tough clay. -_ _ ---- --- 61-87

Glauconitic sand.__-_______-__-____-_--_-_-----.___-_--- 87-89

Sandy shale.__........____.__..__._.....______ 89-91

Gray sandstone.--------------- -_____-__-__«,_____-____-. 91-92

Sandy shale.......__._..._____...________....._.. 92-118

Shale..-- - --- - 118-146

Sand and shale_---_-__--------f-_--------___-_-_.__._.___ 146-160

Dark-brown sandstone---.-.------------------.---------- 160-161

Sandy shale...._. ...... .. .._ _ __ 161-207

Gray sandstone. _-___._..._._______..._.._.... 207-208

Sandy shale. - _____-__.___________.._.__ 208-221

Very fine sand (brackish water)..___--___________-_-__--__ 221-254

Sandstone-_--__--.-.----_------_--__-__-----_---------- 254-255

Well 13 (Na-62)

Pleistocene (?) series: Depth (feet) 

Yellow sand.___--______---__-__-__-_-__.______-______-_---.. 0-4

Fine red sand.--------------_.---_-----.----.---.._..------- 4-7

Eocene series:

Claiborne group:

Cane River (?) formation:

Red sandy clay__-____.___._-_-_..__....._____.____ 7-36

Stiff clay.._.._..._..._.____._______............._.. 36-44

Wilcox formation:

Sand_.___.__..._..___._._.__..___.____._____.______ 44-48

Clay. _ ____ _____ ____.._ ____ 48-54

Sandy clay. ____________________________________________ 54-60

Clay_._._. .._... ........_..___._______._.._______ 60-66

Sand_._______-...____._________________._________.._. 66-70

Sandy shale________-__--___-_______.._.__._.____..___.__ 70-74

Clay -____ _____________ 74-84

Sandy shale___________________________________________ 84-88

Shale-. -------._-_._______ ________ ___ _________ 88-94

Sandy shale___----_--__--_--_______ _________________ 94-98

White sand___ _______________________.__.______ 98-116

Gray shale___..__________._.________________________ 116-150

Lignitic sand__--.--__-...-____..________.____.________ 150-187
192 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 13 (Na-62) Continued

Eocene series Continued

Wilcox formation Continued Depth, (feet) 

Sandy shale___________________________________________ 187-205

Sand...______ __-.---_._._..._...___.__________ 205-210

Fine sand and clay_-_____._..___...______.______________ 210-221

Clay______________.____________________________________ 221-237

Well 14 (Na-14)

Eocene series:

Claiborne group:

Cane River (?) formation: Depth (feet) 

Red clay.__________________________________________ 0-30

Wilcox formation:

Sand_________________________________________________ 30-70

Shale._________________________________________________ 70-95

Sand__-___-.-.__-____________...________._______.____ 95-114

Shale..---__----_____._.____________.________..._..._ 114-132

Rock___-__-__--__-___._..__.__________________.______ 132-133

Sandy shale_-----_--_--___-_---_______________________ 133-150

Tough clay._-_-___.__..._.____._...________..__.__..... 150-189

Sand_______..-_.____..._._____.___________.______...___ 189-200

Rock_________________________________________________ 200-202

Sand (brackish water)__________________________________ 202-231

Rock.._-_-_-_--_...____________________.............. 231-232

Well 16 (Na-63)

Eocene series:

Wilcox formation: Depth (feet)

Red clay_________._____________________________________ 0-15

Sand______________________________________________ 15-68

Tough clay.___________.______________________________ 68-85

Rock______.____________________________________________ 85-87

Tough clay__._._-_-.__-.----.._----.--.---.-------.-_ 87-97

Sandy shale_____._______-___-_______-_-____-__----_- 97-168

Tough clay--_______-____--------_____-____----------.__ 168-183

Sandy shale ______.-_-._________-._._...__-___ 183-200

Rock_____-__._______-__-_--___-_-______-__-.-___ 200-207

Shale._____.____-_.______---___-_--------_-------_---- 207-219

Tough clay-__-__.__.__._...__.____._.__..._.--.-_-... 219-228

Fine sand.....-._._--_-_-_-_--._.__......_..__ _..... 228-238

Shale.____-___-__-_-_-_---_----_----------------------- 238-254

Sand --------------------------------------- --------- 254-269

Tough clay.....-._.-_-_-_-_---------------------_------ 269-290

Sand._____--.---____.-_-___---_-___-----.--------__ 290-300

Toughclay...------.-----..---------------------------- 300-308

Rock____._----____-_-__---_--_---_-__._._.._ 308-310

Shale-____----_--_---------------_---------------------- 310-337

Sand -.-_..-_--..---------------------.-------------- 337-345

Shale._____-_-__-__-----------_------------------------ 345-357

Sand_-_-.____---_-----------.-------------------------- 357-379

Shale..______.--___---------_-------------------------- 379-384

Sand...-----_--______-_-_---.--------------_ ....... 384-399
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 193

TABLE 4. Logs of wells In the Natchitoches area, Louisiana Continued

Well 17 (Na-49)

Eocene series:

Claiborne group:

Cane River (?) formation: Depth (feet)

Red clay____.______________________________________ 0-12

Wilcox formation:

Fine sand, basal part very glauconitic___._________-__-___-_ 12-62

Blue clay_________________________________________ 62-79

Gray sandstone_________________________________________ 79-81

Sand-_______.______________________ 81-90

Rock_____._____________________________ 90-92

Stiff clay____________-_.__-_-_____________._____ 92-100

Very fine sand_____--__--_-_______-_-_-_--____-_____ 100-102

Lignitic sandy shale____________________________________ 102-146

Fine sand_______________________________________ 146-148

Rock________________________________________ 148-149

Gray sandy shale____-__--_-____________.---_-_-_---_-- 149-150

Coarse-grained sandstone-_______-__________-_-__-__-_-___ 150-151

Gray sandy shale with sandstone streaks_________________ 151-180

Fine sand________________________________________ 180-184

Gray sandy shale___.____________________________ 184-188

Fine sand (fresh water)_________________________________ 188-208

Gray sandy shale__---_-______________.-_-_--_____-_- 208-221

Hard gray sandstone___________________________________ 221-223

Gray shale____-._______.______________________ 223-244

Fine sand_____________________________________________ 244-260

Shale.__--_---_--------_-___-__________-_-_-_-___--____ 260-267

Fine sand_______________________________________ 267-283

Shale_____-_--_----_______-_____________________-_-_-_._ 283-301

Fine sand.__________________________________________ 301-326

Shale______________________________________________ 326-328

Sandy shale.______________________________ 328-369

Very fine fossiliferous sand______________________________ 369-374

Rock_________-____----__--_--________________-_-_-_-_._ 374-376

Sandy shale, small gas show____________________________ 376-410

Stiff clay_____________________._______.__ 410-460

Fine sand (salt water)__________________________________ 460-484

Soft lignite.-------------------_-___--__--_----------_-. 484-487

Stiff blue clay___-_-_-_-___________-_--------__-___ 487-520

Gray sandy shale--_------------_-----_---_-----_-------- 520-540

Brittle gray sandstone__________________________________ 540-541

Gray shale____________________________________________ 541-544

Brittle gray sandstone__________________________._________ 544-545

Medium-grained sand.________________________-___----__ 545-547

Brittle gray sandstone______-_--__-_-___-___-_-___-_-_-_-_ 547-548

Sand and shale__-_____________.___._-__--_-_-_-___ 548-559

Hard rock__-------_______._._________________ 559-560

Sandy shale_________-_________________________ 560-562

Hard rock__.____________________________ 562-563

Shale-___--------------------------------------------_ 563-571

Sand. ___ _ .- __ _-_ 571-600

Blue clay_______________________-----_____- 600-605
194 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 18 (Na-50)

Recent alluvium: Depth (feet) 

Redsandy clay_____________________________ ___________ 0-29

Blueclay__.________________ . _ ___._ 29-33

Sand...____________ _____ 33-38

Blue clay___________________...__________._____ 38-63

Sand and gravel____________--_----________________________.- 63-85

Eocene series:

Claiborne group:

Sparta (?) sand:

Blue shale______________________________ 85-125

Cane River formation:

Fossiliferous and glauconitic marly clay ______________ 125-144

Green sandy shale-.---------. _____________________ 144-190

Sandy shale and lignite________________________ .____ 190-219

Sandy shale________________-___-___-_.__--____ 219-230

Stiff clay__________._______________.__ 230-238

Wilcox formation:

Coarse sand (salt water)___--__-_-_-_-_-_._-_-_-_-_-_.__ 238-282 

Shale._______________-._-________.___-______ 282-303

Rock_____________ _-_.___-_-___-_______-_--__.____ 303-304

Shale.-_________-_____--___-__-_-___________-_____-___- 304-309

Rock.____________________.____________ 309-310

Stiff clay________-___.___-_--______-_____._-_-_-_____. 310-315

Rock__________________.______________________________ 315-317

Brittle pyrite sands.__________________._-_-___.______ 317-334

Shale______.__________________________ 334-342

Very fine sand___________._____________________ 342-350

Shale..._____._____.__ .____________________ 350-352

Fine sand___________________________-_-_______. 352-357

Shale.______-.______-_-_---________--_______-___.__ 357-374

Finesand..________________________________..___.__ 374-377

Lignitic sandy shale____________________________ 377-393

Sandy shale__________________________-__ 393-460

Rock._______________.____________...___ 460-461

Sandy shale________________________________ 461-495

Very fine sand_____________________________ 495-506

Stiff clay_____________________________________________ 506-509

Well 19 (Na-61)

Recent alluvium: Depth (feet) 

Red clay____.__--_______________________________ 0-29

Very fine red sand_____________________.__________ 29-67

Coarse red sand_ ____________--__--___-________-__.__-._.___-__ 67-80

Eocene series:

Wilcox formation:

Very fine gray sand___-____-_____-___--__-_-______-_---__ 80-93
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 195 

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 20 (Na-53)

Recent alluvium: Depth (feet) 

Sandy loam_________________________________________________ 0-3

Red sandy clay____________________________________________ 3-14

Dark blue clay______________________________________________ 14-16

Red clay.__-_------_-______.__-___---___-_-__-__--__._-__ 16-30

Coarse yellow sand__________________________________________ 30-46

^Eocene series:

Claiborne group: 

Sparta sand:

Fine gray sand and shale-______-____-___-____________ 46-50

Lignitic shale_________-___-____-_____________.______ 50-52

Coarse gray sand with lignite and shells ________________ 52-66

Hard gray shale________-__-____-_..___-______________ 66-84

Blue and green clay_______--__-_---_-_______-______ 84-106

 Cane River formation:

Rock____________--------_--_-_--------__-_.---_-___ 106-107

Sandy shale____----_----_-------------_----__-----_- 107-132

Shale------_---_---------------------_-----_------_ 132-156

Shale and hard rock layers_____-___-_-_____-_____-____ 156-166

Glauconitic fossiliferous marL________________________ 166-174

Soft shale_-_-_----------_------------------__------- 174-204

Sandy shale .__ _.- _ ..._ _ _--._- 204-212 

Wilcox formation:

Medium-grained to coarse-grained sand with mica, lignite, and 

shells.-------_--------_-----------------_-----------_ 212-240

Sandy shale__._________.--_____-_--__-_______-_.._____ 240-244

Green shale__._-_-_-_----------------------------------- 244-250

Sand with mica, lignite, and shells-________________________ 250-254

Hard shale_______-_-_________.___._.___.__..___._._- 254-255

Fine micaceous sand_____________________________________ 255-258

Shale-_..-_-_-____---_--_.-_---____--_-__--_-__-___ 258-262

Fine-grained to medium-grained sand______________________ 262-274

Stiff clay____-_-_-_--_----_---_-_--__---_-_-__--_---_-_- 274-276

Fine sand____.________-_-_----_-_-___---_.--__--.-_-__ 276-280

Sandy shale-___---_-__------_-_-_-------_-_-__-_______ 280-282

Fine sand and sandy shale__--_-_-----_-----_---_-------_- 282-288

Stiff clay_____---_----_---_---_---_--------_-----_--____ 288-303

Rock___-____________-_-__--___----___--__-__-_-_-____ 303-304

Stiff clay.___..___-_.__--__--------_----------__---.__--- 304-307

Sand______.-----._-____-__----_------_-__.---_--___-___ 307-308

Sandy clay.____________________________________________ 308-315

Medium-grained sand with lignite and shells___-____________ 315-318

Soft shale_______________-.--_-_-_-_.--_---___-_____.__ 318-322

Sand_____._-__----____________--.___---_-___-__-____-_- 322-327

Rock____..__-___-_-_-_-.-_-_-_---_---_---_-_-_..___-_._- 327-328

Sandy shale__.-__---__-_-----_--------_----------_-----_ 328-339
196 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 21 (Na-54)

Recent alluvium: Depth (feet) 

Red sandy loam_____________________________________________ 0-2

Red clay..________.___._._..____.__!___________________ 2-14

Red sandy clay_______________________.______________________ 14-43

Blue clay_______--_-_-____--_-___-_-________,__-__-_--______ 43-46

Soft shale____-___-_-_----__----_____________________ 46-67

Coarse yellow sand __________________________________________ 67-104

Eocene series:

Clariborne group: 

Sparta sand:

Sandy shale__--_-__--_____________________. 104-134

Fine sand with shale partings,________________________ 134-144

Shale_______._________________________ 144-146

Fine sand_____________________..._____ 146-153

Sandy shale_--_-__-______________________. 153-158

Medium-grained sand with shale partings ______________ 158-172

Stiff clay-.___._______________________ 172-218

Hard sand___________________________________ 218-219

Sand___________________-.____________ 219-224

Cane River formation:

Sandy shale___________________..._______ 224-245

Stiff clay_________-____________________________ 245-271

Glauconitic sand____________________________________ 271-273

Hard shale_____________________.________ 273-296

Hard fossiliferous marl_________________________ 296-301

Green shale with sand streaks_________________________ 301-310

Soft shale___________________________ 310-315

Hard shale__ L _________________________ 315-318

Hard brown shale___________________________ 318-325

Soft shale with shells and glauconite___________________ 325-336

Sandy shale______________________________ 336-349

Wilcox formation:

Fine sands, shale, and lignite____________________________ 349-366

Medium-grained sand____________________________________ 366-380

Rock______________________________________________ 380-381

Sandy shale and lignite______-_____________-___-__________ 381-38g

Sand____________-_.--_______________-_-_-_._-__ 388-39g

Sandy shale__________________________-------_-__ 398-40$

Fine sand______________________________________________ 406-415

Sandy shale, lignite, and shells____________________________ 415-42j

Coarse sand with shells_________--_________-_____--____-__ 421-430

Sandy shale_______________________._____-____ 430-432

Stiff clay.._______________________________ 432-43

4

Well 22 (Na-56)

Recent alluvium: Depth (feet) 

Waxy red clay______________________________________________ 0-20

Blue-gray clay______________________________________________ 20-25

Yellow-gray j clay with concretions.____________________________ 25-35

Fine red sand-_-_-______--__----__---_--__-___-_------_---_- 35-43

Stiff blue clay________________________________ 43-58
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 197 

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 22 Na-56 Continued

Recent alluvium Continued Depth (feet) 

Medium-grained yellow sand_-_---_-_-_-________-__-_---_-_-__ 58-70

Coarse yellow sand and gravel._______________________________ 70-101

Eocene series:

Claiborne group:

Cook Mountain formation:

Shale, shells, lignite_____-______-_--_-_____-___----_ 101-104

Green clay______________________________________ 104-108

Yellow-gray shale_._._______._________________ 108-115

Gray clay__________________________________ 115-132

Sandy shale______._--._--_---__._-__________ 132-150

Shale._____--__----_-----_------------_-_---------_ 150-155

Sparta sand:

Gray sandy shale_____________-_-_-__-_-__----__-_--_ 155-176

Fine Band-.--.... . - . - . 176-188

Sand and shale______.._____._-_-.-_____.__ 188-232

Fine sand____-____________-__.______.__ 232-234

Sand and shale ._ _.. 234-262

Fine sand._-_ ------- 262-279

Gray shale-.. -- - -.. 279-286

Fine sand--.- 286-300

Sandy shale... _-____-_._-____ 300-314

Fine sand__ 314-328

Stiff gray clay______--___--___-_._-____-----_- 328-345

Gray shale 345-375

Stiff gray clay____________---___-_._._____.___--_ 375-390

Fine sand 390-400

Sandy shale 400-402

Fine-grained to medium-grained sand-_________________ 402-415

Cane River formation:

Sandy shale__ _ _ _ __ 415-426-

Rock__.______.__.________________________ 426-427"

Sandy shale_______________________________________ 427-468

Stiff clay_._________________________________ 468-480

Glauconitic sandy shale______________________________ 480-494

Shale._________-_._._____.___._______._ 494-500

Hard marly clay___________________________________ 500-504

Sandy shale__-__--__--__-__-_________-____________ 504-508

Stiff clay._____________..---___-_-____-___________._ 508-527

Glauconitic sandy shale__ ____________________________ 527-550

Wilcox formation:

Medium-coarse san d with shells and lignite _________________ 550-596

Fine sand and shale____________________________________ 596-637

Sandy shale_________________________________________ 637-644

Medium-grained sand.-_-____,--__-____-.________________ 644-684

Sandy shale__-__-____-__----__--____-_____-___________ 684-691

Fine sand_____________________________________________ 691-694

Rock___________..__-_--___..____.____.__.______ ..... 694-695
198 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

WeM 23 (Na-57)

Recent alluvium: Depth, (feet) 

Red soil-__-__._____.__________ .._._.__..__.__...__.._..____ 0-1

Red sandy clay____________________________________________ 1-21

Pine red sand___________-______________.._______..____.___ 21-32

Red sandy clay____________________________________________ 32-34

Fine red sand__ __ __ ____ ______________ _______ _________ 34-47

Medium-grained red sand___________________________________ 47-71

Decayed wood-_____________________________________________ 71-73

Coarse red sand__ _______-____ ____ _ _ __________ ________ 73-93

Eocene series:

Claiborne group:

Cook Mountain formation:

Soft red clay _________ _ _ _ _ ______________ _ _____ 93-106

Soft red clay with rock layers-..-----..__.-.__________ 106-119

Soft red clay..______-_._-_..___._.._._......_.__ 119-130

Soft red clay with rock layers.-_______________________ 130-149

Soft red clay___..._._....._......____._._.__ 149-164

Rock layers with shells.-.--..--...-._____..__..______ 164-170

Stiff yellow clay__..__________________._.._._._ 170-188

Gray shale with rock, lignite, and shells___._-_._.______ 188-198

Hard shale with lignite and shells___-__-__-----_--___ 198-220

Stiff gray clay___.__________________........_.. 220-230

Hard gray shale......._._.._..._.__.__!_.._._...._._ 230-246

Sandy shale with shells_._-._____.._._____.___.___ 246-270

Stiff clay._.__-._._.._._...__..______..__.._._ 270-282 

Sandy shale__--.-----_-___-____...._..___.________ 282-317

Sparta sand:

Very fine sand.__-._._._.._..._._.._____..._________ 317-332

Shale.__..........__.._._..._..._._._._....__...._. 332-347

Medium-grained sand._______________________________ 347-368

Fine sand and shale________________________________ 368-399

Stiff clay....____.._________________________________ 399-409

Fine sand_-_____-___________________________________ 409-426

Sandy shale and lignite................_._--..__-_____ 426-442

Sand_______________________________________________ 442-460

Shale.___----..-_---.-------------_----.-.-.-....-- 460-472

Fine-grained to medium-grained sand____-___-___._-___ 472-509

Fine sand with shale partings.________________________ 509-538

Fine-grained to medium-grained sand__________________ 538-595

Cane River formation:

Shale__________ ____________________________________ 595-602

Sandy shale_____ _-___ _-_-_-_ _- _-- -_ -_. 602-626

Hard shale, shells, and lignite...___._.__._-_-_._..-___ 626-674 

Glauconitic marly clay._____--_________-_-_-__-______ 674-682

Stiff clay..------...-_--.------.-----------------.-- 682-706

Sandy shale___ ______ --_-_ _-___-_. - 706-715

Rock...--.---.---..-.----------------------------- 715-716

Shale--.--.---------------------------------.--.-- 716-720

Hard lime rock. __________________________________ 720-722

Sandy shale __________________ _._______________ 722-727
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 199 

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 23 (Na-57) Continued

Eocene series Continued

Wilcox formation: ^eptft (feet) 

Fine lignitic sand (soft water)._._.__..___.._______________ 727-766

Sandy shale______. .__-____---___ .._.__.__._ 766-778

Sandy shale with rock__________________________________ 778-785

Sandy shale_______________________________________ 785-820

Fine silty sand (salt water)___________________._____ 820-848

Sandy shale___.____...._____.-.__......._.... 848-852

Fine sand and shale__________________________________ 852-860

Sandy shale_____________--_-_______.-_-_-_---_-.__ 860-862

Fine sand_____________________-_-____-_-_-_-_-_____ 862-865

Sandy shale__-_____--___-_---_____-_-___---___--______ 865-875

Fine sand____..__.___. _-.._.-..__...__.._...._..___.. 875-877

Brown sandy shale______--__-____-__-__-___-____-_____ 877-888-

Fine sand______-___-___-_--___________._____-_-_.___ 888-898

Hard rock______._._.___________________________ 898-900

Sandy shale__,__.________________________.__.____... 900-914

Stiff clay_-________ .-_-_.__. .___-_____ .___.. 914-920

Fine sand (saltwater)__________________________________ 920-934

Shale._________________________________________________ P34-941

Sandy Bhale.__.-__-_.___-_----_____-___.______________.. 941-948

Shale.___-_._-__--__-------.________--_-____-__.___ 948-952

Fine sand (salt water and gas)____________________________ 952-991

Well 24 (Na-55)

Eocene series:

Claiborne group:

Cook Mountain formation: Depth (feet) 

Red clay with ironstone gravel___._-__________________ 0-4

White bentonitic clay._______________________________ 4-24

Red ferruginous sand________________________________ 24-28

Mottled shale with shells and selenite crystals__ _______ 28-48

Hard green shale.___________________________________ 48-53

Yellow and brown shale with shells-___________________ 53-59

Rock with lignite____________________________________ 59-61

Sandy shale and lignite______________________.________ 61-70

Soft mottled shale_---___-_-_-__-_-__________________ 70-80

Gray shale with rock layers.________________!_________ 80-84

Soft shale_________________________________________ 84-88

Fine sand.________________________________________ 88-92

Stiff gray clay___-_----___--____--_________________ 92-105

Hard gray shale_._--_-__.___________________________ 105-122

Gray sandy shale.___________________________________ 122-158

Mottled sandy shale with selenite crystals-_____________ 158-173

Sparta sand:

Hard fine sand and lignite.-_--___---___-_____________ 173-200

Sandy shale________________________________________ 200-213

Fine sand_______________________________________ 213-222

Shale.--___-_-___----____________________________ 222-225

Fine gray sand and lignite_--____-____________________ 225-248

f
 200 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 24 (Na-55) Continued

Eocene series Continued

Claiborne group Continued

Sparta sand Continued (Depth feet) 

Medium-grained sand with lignite-____________________ 248-266

Lignitic sandy shale_________________________________ 266-294

Fine-grained to medium-grained sand___-____-..-_____. 294-386

Stiff clay._._..___.__________..._.______.__..___ 386-400

Sandy shale-__-____- _______________________________ 400-430

Medium-grained to coarse-grained sand.---____________ 430-448

Cane River formation:

Stiff clay_._ ___.__________________________________ 448-464

Hard shale_____i______________________________._._ 464-475

Stiff clay_-__-________._______________ _____________ 475-488

Shale. ___----_-_-___.__..__-_.__-__._________ 488-500

Stiff clay_-----_--_-__,-_-_____----_--_-________._ ._ 500-522

Glauconitic marl rock_________________-._____________ 522-526

Glauconitic sandy shale with shells____-__--_-_-_______ 526-548

Stiff clay_--------_--_----__--_------_------._-.__ 548-578

Wilcox formation:

Coarse sand with lignite and shells____________---_-_-__-___ 578-609

Sandy shale_.___________________________________________ 609-639

Coarse sand_______.__.__-__-____----___________.______ 639-684

Shale.______.-----------_-------__-------_--------._-_- 684-699

Sandy shale___________________________________________ 699-703

Rock____--.-_------------------------------------------ 703-704

Well 25 (Na-68)

Recent alluvium: -D«P*A (/««*) 

Red sandy loam___-_--_____---_-_--___-__----_---__-__-___-- 0-1

Black sandy clay_______-___--__-_-__-_-_-. __-..--_--_-__-__-_ 1-3

Red sandy clay____ .__-____.__-____-__-___-_-__---_--_____- 3-10

Fine red sand.______________________________________________ 10-12

Red sandy clay__________---____-____--____--_----__----._- 12-26

Stiff gray clay__________-------_-___-__-___.. 26-52

Red clay _________. ------_____________________...___- 52-59

Coarse red sand with shell fragments_________________ .__ .____ 59-71

Eocene series:

Claiborne group:

Cook Mountain formation:

Gray shale and silt. _______-____ __------___--_-___- 71-84

Sparta sand:

Sandy shale____________________________________ 84-104

Fine sand _.-----_-_-----_--_------------------....- 104-110

Sandy shale and lignite_____________--_----______-__ 110-128

Fine sand .,-------------------------------------- 128-147

Sandy shale and lignite______._----_-___.--__.____ 147-180

Stiff gray day________________ _-- - --.-------- 180-195

Sand and shale. -.--_-.--------------------------- 195-212
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 201 

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 25 (Na-58)-Continued

Eocene series Continued

Claiborne group Continued

Sparta sand Continued (Depth feet) 

Sandy shale_______________________________________ 212-226

Sand__--___-_-__-------_. _-_-_____-_-____-_-___-___ 226-236

Sandy shale and lignite_____________________________ 236-258

Coarse sand and lignite__. __________________________ 258-269

Stiff clay _ . __ 269-300

Shale and lignite____________________________________ 300-308

Stiff clay _ .- __ __ -_ 308-336 

Sandy shale_______________________________________ 336-348

Fine sarid_________________________________ 348-356

Cane River formation:

Hard shale with streaks of sand and lignite _____________ 356-365

Hard shale with shells and pyrite and lime concretions.-.. 365-427 

Stiff clay_____________________________________ 427-436

Hard marly clay with hard layers_-_--_--_-__--__-_--__ 436-442 

Stiff clay_ _____________________________ 442-466

Shale'and shells__---_-----_______.__________________ 466-470

Hardshale_____ .____________________________ 470-476

Sand shale_________________________________ 476-490

Wilcox formation:

Medium-grained sand__ _______________________________ 490-538

Sandy shale______... __________________. 538-549

Finesand____....______.______._--______-____.___ 549-558

Sandy shale__ _ ,_ _____ ____ __----- 558-567

Hard rock_________-_-___-_-____________________________ 567-570

Hard sandy shale____________________________________ 570-588

Fine sand___________________________________________ 588-590

Hard rock______.___________________________________ 590-591

Red shale___________________________________________ 591-596

Fine sand__.______-____________.-_-____-._________ 596-602

Shale____-_-_-----_----_-_____.._._._______._______ 602-614

Hardrock___________ ________________________ 614-618

Shale______--_____--_________________________________ 618-626

Sandy shale with hard layers__________________________ _ 626-638

Stiff clay__________________________________________ 638-645

Sandy shale_________________________________________ 645-655

Medium-grained sand____________________________________ 655-673

Sandy shale, shells, and lignite____________________________ 673-688

Sand_____________________--__ .---_------_._________ 688-699

Shale, shells, and lignite___________________________..___.__ 699-708

Sand__._____-__-___-_ T __-____._________________________ 708-722

Shale and lignite._____________________________________ 722-730

Fine sand, lignite, and shells___-__________________________ 730-782

Shale_________________-__--________________________ _ 782-790

Fine sand and shells.______________ ______________________ 790-807

Hard shale with pyrite_.___-_-____________________.______ 807-813
202 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 26 (Na-59)

Eocene series:

Wilcox formation: Depth (feet) 

Sandy loam.___ .________________-_______________________ 0-3

Red sandy clay______-____________-_-_______-_____-______ 3-10

Red clay.-___-_------_________..____._.._..._ 10-18

White clay___._-.-__-____.__-_________________ 18-24

Fine white sand (brackish water)_____________________.____ 24-30

White clay_________________________-_.__--_--___-_. 30-31

Lignitic sandy silt______-___________________-____________ 31-45

Light-gray shale_________________________________________ 45-49

Fine-grained to medium-grained gray sand (brackish water) _ 49-67 

Gray sandy shale and lignite_-____________________________ 67-95

Lignite--__---_-__---------___-_____-_-__-__-_._____ 95-97

Fine lignitic sand (brackish water)_________________________ 97-108

Red shale-_______-_...__-----_____-_______ 108-122

Fine red sand (brackish water)____________-____-__----____ 122-136

Ironstone__-___-____--_-_-__-__.______________________ 136-138

Fine blue sand___.________________________._-__.____ 138-144

Soft brown shale__---__-______-______--_______________ 144-155

Dark-gray shale.___--__-_-_____-_--____-____--_______-__ 155-170

Sandy shale______...______________________. 170-194

Fine blue sand._____________________________________ 194-206

Soft gray sandy shale-____-__--___--__--_--_-_-_-________ 206-248

Fine gray sand. _______________________ j_,j. _______________ 248-254

Soft gray shale_-___-----_-___-____-___________________ 254-275

Fine sand___________________________________________ 275-290

Soft gray shale with shells...____________________________ 290-294

Fine dark sand______________________________________ 294-315

Gray sandy shale___________________________________. 315-326

Hard rock._________________________________________ 326-330

Gray shale___-___--__--_--___-__--_--_--_-____________ 330-350

Fine sand________________________________________ 350-374

..Soft gray shale..__-_---________-_--_-_-_____-__-______ 374-391

, Soft brown shale and lignite-_--_-___--_--______----_--___ 391-430

. (Hard rock-__.________________________._____ 430-431

Soft shale and lignite_____________._-_--_---___.____ 431-486

. . 'Hard shale______.._..._____________.._____ 486-488

Soft sandy shale____-_-___._.___-__.___-___-_-.______ 488-510

Fine sand__________________________________________ 510-514

Sandy shale_____________________________________ 514-520

Hard clay_____-__-_--_.___________-_____._________...__ 520-534

Hard rock____________________.._-__._________ 534-537

Stiff clay___________.._____________._______ 537-556

Well 27 (Na-60)

Recent alluvium: Depth (feet) 

Red sandy loam_____________________________________________ 0-3

Red sandy clay____________________________________________ 3-10

Fine red sand_______________________________________________ 10-14

Red clay____._______._____._______..___.____ 14-35

Fine red sand_______________________________________________ 35-40
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 203

TABLE 4. Logs of wells in the NatcMtoches area, Louisiana Continued

Well 27 (Na-60) Continued

Recent alluvium Continued Depth (feet) 

Brown clay._..-__________--__-_--____-----_-____----_--____ 40-65

Soft blue sand shale_______--___---____-_----_-------._.._ 65-70

Coarse red sand and gravel with shell fragments---__.___..___.__ 70-95 

Eocene series:

Claiborne group:

Cane River formation:

Soft gray shale___.._._.--__..._.._._______-_.. 95-128

Gray shale with shell fragments--_-___-_-__-_,________ 128-143

Soft gray fossiliferous marl and glauconite______________ 143-149

Soft gray lignitic shale__----_----_,___.-_-__--__-____ 149-195

Wilcox formation:

Fine gray sand_______________.__-_---_---_---_-__--.__ 195-20&

Brown shale and lignite-_____---_---_--__--_____-____--__ 208-214

Fine gray sand________-_____---_-_-_.___-__.-_-_---_._ 214-232

Alternating sand and shale sand___________________________ 232-242

Soft green sandy shale__---__---------_-----_---------___ 242-270

Alternating sand and shale__--_____--___-_-__-__--_-____ 270-295

Hard clay___.__________________________________... 295-299

Soft gray sandy shale___--_-_--________________________ 299-331

Hard sandstone-______-_--__---------------_-_-------___ 331-334

Green sandy shale.__________--_-__-_--__--__--__________ 334-341

Fine sand_____________________________________________ 341-346

Soft gray shale.__-__-__-____-------------------_------ 346-350

Fine sand_____________________________________________ 350-366

Soft gray shale-___---__-____--------------------- ------ 366-369

Fine sand____________________________________________ 369-381

Sandy shale___________________________________________ 381-398

Rock with pyrite..-------------------------------------- 398-402

Fine sand______._.__________________________________ 402-410

Sandy shale___________________________________________ 410-42&

Fine sand_____________________________________________ 428-436

Sandy shale with hard layers.____-_-----__---_-_-____-____ 436-446

Medium-grained sand____________________________________ 446-460

Hard rock______________________-_---___-___-_---_______ 460-461

Well 28 (Na-61)

Eocene series:

Claiborne group:

Cook Mountain formation: Depth (feet) 

Black soil_________________________________________ 0-1

Yellow clay with selenite crystals.______________________ 1-16

Gray shale____________________________________ 16-39

Gray sandy shale with shells____-___-_-_______________ 39-48

Hard shell layer__._______-__-_---__,-_____________ 48-50

Stiff clay..____________..__.___.._____ 50-76

Sandy shale________-__--------____----_____.______ 76-96

Sparta sand:

Soft shale.______________________-----__________ 96-118

Fine sand___..._______________________________ 118-138

827625 49 4
204 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 28 (Na-61) Continued

Eocene series Continued

Claiborne group Continued

Sparta sand Continued Depth (feet) 

Stiff clay.---------------------------_------_--___-_ 138-150

Soft sandy shale___________________________________ 150-208

Coarse sand__ _____________________ .___..____ _______ 208-223

Fine sand________ ._____-_..__---_-____--___________ 223-225

Medium-coarse sand_-___ _--_-_--________..___._____ 225-252

Fine sand__________________________________________ 252-262

Sandy shale with lignite and shells__ ______ _____________ 262-278

Sandy shale_______________________________________ 278-309

Fine sand __________________________________________ 309-339

Shale.___---------------------------------------__. 339-347

Fine sand__________________________________________ 347-372

Cane River formation:

Hard shale_________________.__-_____.-_.-__.______ 372-438

Sandy shale-_--__--_--------_---_- _________________ 438-446

Hard marly clay____________________________________ 446-454

Stiff clay______-----------_-----------------_-_.-___ 454-465

Hard brown shale___________________________________ 465-472

Soft green shale____-__________________________ 472-501

Wilcox formation:

Fine to medium-coarse sand with shells ____________________ 501-550

Sandy shale_____________________________________ 550-556

Fine sand_ ______________________________________________ 556-562

Sandy shale___-._____________________________________ 562-564

Fine sand____-__-----___-_-_-_---_--------------_.-.__ 564-572

Hard shale._______ .______-__--_-_----_-__-___-_-_.__ 572-575

Hard rock___.__________________________________________ 575-577

Soft shale and fine sand________________________..____.____ 577-588

Hard rock._____________-_--_-___-_-_-_,_---__--___-_-__ 588-589

Sandy shale___-____-_______-----__-______-__-_-__-____ 589-594

Hardshell bed______..__-___ -__..-______ ___--________ 594-595

Shale_____--__--__ ------- - -__----- - 595-598

Sandy shale___________-_--___--_--_-_-____-_-____-.._ 598-604

Rock (gas)___--_-.._--_---__-_-_----._____._____._ 604-607

Hard shale__ _________-___-___-_-_-__-_-------_.______ 607-620

Sandy shale___..____-___-_-_-___-____--_-_-___-_-__-_ ._ 620-636

Stiff clay_______________________________________ 636-646

Shale._ _______--__-___--_-----_--__-_-_-__-------___-. 646-654

Pyrite nodules. ______----___-----__._____________.._ 654-658

Sandy shale______._____-__-_----___-----_--_-_--_-_-.- 658-660

Stiff clay___ _--- -- -------- ----_-...- .. ___- 660-672

Sand and shale.__.___..__ ___________________________ 672-682

Hard shale.________________________________________ 682-692

Hard g!imbo____.-___-_ ._____._ .__.-__-__-____--____ 692-706

Fine sand (brackish water) _______________________________ 706-716

Shale.__________________-------------_----_----_-__ 716-724

Sandy shale_____.________________.-____-_---_-_-______ 724-740

Stiff day_________ _ ________________________ _ _________ 740-750
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 205 

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 29 (Na-27)

Recent alluvium: Depth (feet) 

Clay__----.. 0-20

Sand and gravel------ _.__ _-_ - _ 20-100(7)

Eocene series:

Glaiborne group: 

Sparta sand:

Sand .-. 100(?)-294

Shale_._ 294-350

Cane River formation:

Stiff clay--._._.._._._..._.._.__._.._. .__.___._. 350(?)-500 

Wile ox formation:

Coarse sand_____-_ _ ____ _._ __ __ _ 500-550

Well 38 (from old records)

Recent alluvium: Depth (feet) 

Surface clay____ __- _ _ - _ _ . _ -_ ___ 0-45

Blue clay-_--_----_.---------------------------------------- 45-47

Sand --------------------------------------------------- 47-60

Eocene series:

Claiborne group:

Cane River formation:

Sandy clay, shells, lignitic material-____________________ 60-85

Clayl-- 85-100

Grayish sand__.___. ___ -___ _____ - _ 100-125

Soft shell rock_.__ _.._._...____.__.___....___.__ 125-135

Hard clay._ _ 135-145

Greenish hard rock__ _ ..._ __ _ _ 145-146 

Wilcox formation:

Black shale with lignite.__-._----___-_-_-__-______----___ 146-175

Coarse sand (salt water)________________________________ 175-195

Black, shale....._.___ __.._-_._____-._._._._-.-._ 195-204

Hard and soft rock____... _________.__.__ ._..___ 204-230

Shale - . - 230-270

Tough clay--------------------------------------------- 270-280

Red sand-.-.--___ .. 280-318

Gray sand- ..... ___..___ 318-325

Shale and clay 325-338

Hard rock with pyrite__ 338-340

Sand (salt water). ._ 340-350

Shale and clay._____.. ___._...__.._...__._.____.._._ 350-390

Sand...._. __. -------------------------------------- 390-410

Clay 410-420

Shale, clay, and lignite..-._ _ _ _ - __ 420-450

Shale... . 450-470

Hardrock __ _ _ . ._._ . 470-472 

Shale... . . - 472-500

Fine gray sand 500-530

Sand__._______._. ..._.________.___._____ 530-560

Stiff clay-.. . _ _ 560-563

Brown rock, gas show_-_-____--___--_________.__-___-_--_ 563-575

Fine sand_____.____.-...._.-__-_..--..___.__...__-_._. 575-580
206 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

Well 38 (from old records) Continued

Eocene series Continued

Wilcox formation Continued Depth (feet) 

Clay and lignite____-___.______________._-----_._____ 580-600

Shale.__________________________---_--__--._ 600-615

Lignite and shale_____________-__ ______---___-_-___ 615-630

Black and gray shale__-__--_-________._._._._____ 630-725

Stiff clay_____ ____ _____-- _ _______-__ --____ 725-735

Soft shale_._-_._-_-_ -_-----_-_---_-__.__..___-__--___ 735-745

Stiff clay____________._._________________..._ 745-750

Shale and boulders______ _ _ _ _ _______--_---__ 750-785

Stiff clay___ __ __ _--______.__-_._ 785-810

Fine gray sand, gas show__ _ _ __ ______ _ _________ 810-825

Blue sandy shale_________ _--- _-_-_ 825-838

Shale.________________________----__-_---__ 838-841

Fine sand_______________ _ _______________________ 841-845

Shale-____________________________________ 845-853

Stiff clay_.________________.___________.___ 853-856

Shale._._________________.______-_-___.__-_ 856-860

Hard black shale. . __-_______ ________ ______ 860-875

Fine blue sand with shells.. -___-__---_-_--___.-_-_-_-____ 875-890

Hard clay_______.______________________________________ 890-895

Clay__._.____________ __ __ ___-__--____.____ 895-940

Hard shale......________________________________________ 940-960

Black shale _____________ __ _______________ _ _____ 960-973

Sand____._.____________________________________________ 973-995

Rock.._._ _ _____________ _ __-___--___ 995-997

Blue clay__________________________________ 997-1000

Benedum-Trees Oil Co., Caryer No. 1

Eocene series:

Claiborne group:

Sparta sand: Depth (feet) 

Sand__. _ __-__ -_-_ -___-_-____- __ 0-217

Cane River (?) formation:

Shale and sand____._____________________________ 217-300

Rock___.____...____________-_.-_._-__ 300-304

Shale__________________-__---_---_-_--_-_-_--___ _ 304-325

Wilcox formation:

Sand__________ _ _ _________ _ ____________ _ ________ 325-355

Sand and shale ____________________________________ 355-407

Shale, sand, and boulders___.___-_._____-_._._____ 407-800

Sand and shale____________________--___,________-_^_ 800-1060

Total depth of well, 5,339 feet.

A. F. Carter, Cnlpepper No. 1

Eocene series:

Claiborne group:

Cockfield formation: Depth (feet) 

Clay----_____-_-_------------_--------- 0-10

Sand_-__ ____ _ - -_-_ --_ ____________ 10-70

Shale. ____________-___________-_-_____- __-_-_-___ 70-88
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 207

TABLE 4. Logs of wells in the NatcMtoches area, Louisiana Cortinued 

A. F. Carter, Culpepper No. 1 Continued

Eocene series Continued

Claiborne group Continued

Cockfield formation Continued Depth (fed) 

Sandy shale______.___._________________ 88-94

Sand___________________________.___.__ 94-118

Sandy shale________________________________ 118-127

Coarse sand_______________________________________ 127-165

Cook Mountain formation:

Shale.___________________________________________ 165-214

Sand_________________________________ 214-224

Shale._________________________________ 224-228

Sand____.__________________________________________ 228-236

Shale.________________________________________ 236-249

Sand_____________________________________ 249-255

Shale._____________________________________ 255-285

Sand___________________________________ 285-294

Sandy shale_______________________________________ 294-310

Sand_.___________________________________ 310-319

Sandy shale_____________________________________ 319-350

Fine sand___________________________________ 350-369

Shale._____________________________________ 369-375

Marl rock____._______________________________ 375-385

Shale________________________________ 385-390

Sand_____________________________________ 390-398

Shale._____________________________________ 398-409

Sparta sand:

Sand___________________________________ 409-462

Shale.___________________________________________ 462-470

Sand_______________________________________ 470-509

Shale._________________________________________ 509-513

Fine sand__________________________________ 513-527

Shale. __________________________________ 527-542

Coarse sand____________________________ 542-608

Shale.__________________________________ 608-611

Sand_____________________________________________ 611-621

Shale._____________________________________________ 621-623

Coarse sand_________________________.-_-.___ 623-686

Shale______________________________________________ 686-692

Cane River formation:

Shale.________________________________ 692-709

Sandy shale___________________________ 709-737

Shale._____________________________________________ 737-776

Marl rock______________._________________________ 776-786

Shale.___________________________________________ 786-822

Wilcox formation:

Fine sand and shale_______.__-_________________ 822-833

Sand______________________________________ 833-852

Shale._______________________________________ 852-857

Sand________________________________________ 857-894

Shale._________________________________________________ 894-900
208 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 4. Logs of wells in the Natchitoches area, Louisiana Continued

A. F. Carter, Culpepper No. 1 Continued

Eocene series Continued

Wilcox formation Continued

Sand__________._-__.___-__.__-___._-_.-.....____ 900-934

Shale____-__._-_-----_---___----__----_--_.- --_---- 934-945

Sand__._..___..._-_-__.__-_-___--_-_-_--_-._-----_.-_-- 945-972

Shale-.-_____________.__.___.__.__.-. 972-985

Sand____________-------______-_---_-_---_---__-__ 985-990

Shale.__________-__--_------_--_----_-._-____-_-_ 990-993

Sand..._.-.-__._--__-_-_----------------------_____-._ 993-1000

Total depth of well, 3,329 feet.

TABLE 5. Mechanical analyses of sand samples from wells in the Natchitoches area,

Louisiana

Well No.

11 (Na-62). .......

13 (Na-62)........

17 (Na-49). _._..-.

19 (Na-nSl). .......

20 (Na-53). .......

21 (Na-64). .......

22 (Na-56). .......

Depth of 

sample 

(feet)

24-29 

29-10 

40-51 

51-61 

221-254

66-70 

98-116 

150-187

29-51 

196-208

67-69 

80-93

30-40 

40-48 

52-59 

59-65 

212-221 

221-231 

231-239

67-77 

77-84 

84.104 

146-152 

161-167 

167-172 

218-224 

359-370 

370-380 

380-391 

391-400 

400-410 

410-416 

420-429

58-69 

69-75 

75-90 

90-100 

100-101 

178-185 

314-323 

390-400 

400-415

Mechanical analysis of sand fraction 

(percent by weight)

8-4 

mm.

.22

4-2 

mm.

0.21

.04

.10

.07

9.23 

.50 

1.39 

1.18 

.91 

1.11 

.65 

.58

.35

3.73

.14

2-1 

mm.

0.16 

.94 

.49 

.31

.44 

1.62

.10 

.40

.05 

.09 

.08

.19 

8.38 

2.06 

.91 

16.44 

8.96 

30.89 

4.58 

8.94 

7.84 

10.51 

6.00 

6.45 

10.53

.01 

.07 

.28 

7.95 

91.14 

.60 

3.36 

.11 

.07

1-H 

mm.

4.70 

1.47 

.70 

.53 

.35

.97 

.24 

.16

2.97 

2.15

4.84 

1.50

2.82 

3.00 

.34 

.64 

3.53 

5.31 

16.88

33.78 

50.94 

29.17 

8.17 

31.74 

42.62 

29.02 

10.51 

30.75 

21.03 

31.28 

31.43 

26.85 

18.90

2.02 

.13 

26.21 

47.52 

7.00 

9.30 

5.05 

.70 

.35

H-W

mm.

11.26 

1.96 

5.74 

2.82 

1.74

8.71 

3.35 

4.42

52.88 

7.36

58.10 

3.67

45.37 

53.78 

51.04 

77.68 

15.84 

36.13 

40.49

63.76 

39.01 

62.23 

57.97 

39.69 

37.92 

22.67 

19.45 

38.17 

37.68 

38.49 

45.66 

40.60 

66.62

26.00 

36.56 

58.54 

40.20 

1.51 

26.55 

15.57 

6.76 

5.65

H-li 

mm.

78.89 

92.63 

90.93 

90.08 

48.48

58.80 

68.21 

89.00

42.18 

73.20

36.18 

48.30

48.00 

39.28 

39.61 

21.48 

74.88 

54.86 

39.48

2.17 

1.63 

6.54 

17.82 

5.58 

6.54 

4.21 

62.42 

19.89 

30.65 

18.28 

15.19 

24.88 

3.17

34.37 

49.18 

14.75 

3.03

42.15 

59.11 

74.73 

66.35

J6-Me 

mm.

4.99 

3.00 

1.93 

6.26 

49.43

31.52 

28.20 

6.42

1.49 

15.67

.72 

46.13

3.81 

3.94 

9.01 

.21 

5.70 

3.61 

3.07

.04

15.13 

6.48 

3.96 

3.98 

2.54 

.86 

1.62 

.53 

.61 

.57 

.20

37.60 

14.06

1.30

21.40 

13.18 

17.70 

27.44

Geologic 

formation

Wilcox. 

Do. 

Do. 

Do. 

Do.

Do. 

Do. 

Do.

Do. 

Do.

Recent. 

Wilcox.

Recent. 

Do. 

Sparta. 

Do. 

Wilcox. 

Do. 

Do.

Recent. 

Do. 

Do. 

Sparta. 

Do. 

Do. 

Do. 

Wilcox. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do.

Recent. 

Do. 

Do. 

Do. 

Do. 

Sparta. 

Do. 

Do. 

Do.
GROUND-WATER EXPLORATION, NATCHITOCHES AREA, LA. 209

TABLE 5. Mechanical analyses of sand samples from wells in the Natchitoches area,

Louisiana Continued

Well No.

22 (Na-56) Con.

OQ /Ma ^7^

24 (Na-55). .......

5C(Na-58). .......

Depth of 

sample 

(feet)

550-570 

570-577 

577-587 

587-599 

599-610 

644-662 

662-673 

673-684

38-48 

48-00 

60-70 

73-80 

. 80-90 

90-93 

317-331 

347-355 

355-365 

365-376 

376-387 

387-399 

409-418 

418-426 

442-450 

450-460 

472-481 

481-492 

492-503 

503-509 

526-536 

536-545 

545-556 

556-567 

567-577 

577-588 

588-593 

593-595

217-259 

259-266 

294-302 

323-344 

344-365 

365-376 

376-386 

430-438 

438-446 

579-589 

589-599 

599-607 

639-641 

641-652 

652-662 

662-673 

673-682

63-71 

104-105 

128-135 

135-145 

226-236 

260-269 

348-356 

490-495 

495-506 

506-516 

516-527 

527-538 

550-558 

664-673

Mechanical analysis of sand fraction 

(percent by weight)

8-4 

mm.

4-2 

mm.

.06 

.02

.06

.08

.05

.03

.28

.41

.07

.01 

.05 

1.71

.09

.14

.51 

.37 

.05

.06 

.11

2-1 

mm.

.50 

1.03 

.30 

2.02 

.09 

.08

.04

.10

.18 

.08 

.11 

.32 

.34 

.26 

.10 

.13 

.12 

.10 

.06 

.15 

.10 

.31 

.22 

.24 

.12 

.17 

.07 

.05 

.03

.09

.16 

.05 

.57 

.34

.31 

.04 

.15 

.01 

.16 

.17 

.50 

1.00 

2.25 

.06

.06 

.04

.03 

.12 

.22 

.01 

.69

1.18 

1.38 

.66 

.10 

.34 

1.49 

.15 

.30

l-H 

mm.

10.11 

24.12 

8.90 

25.71 

3.65 

.21 

.10 

.28

.11 

.21 

.08 

.57 

.48 

8.62 

.35 

.66 

5.40 

2.74 

2.47 

1.09 

.77 

.63 

.64 

.96 

3.27 

2.74 

.37 

1.45 

1.93 

1.45 

1.38 

.30 

.46 

.16 

.21 

1.64

.37 

.28 

.83 

.45 

.20 

.44 

.99 

1.62 

' .67 

.74 

9 20 

9.36 

12.04 

3.31 

4.03 

5.09 

4.56 

18.15

5.56 

5.84 

.24 

.03 

1.35 

.06 

1.76 

6.15 

4.07 

6.33 

14.44 

25.60 

4.52 

1.14

tt-H 

mm.

54.48 

63.36 

65.14 

60.34 

31.16 

8.19 

7.58 

10.02

.16 

4.11 

77.27 

52.78 

94.71 

86.18 

2.04 

3.96 

6.44 

6.57 

8.28 

10.35 

23.33 

7.99 

13.24 

11.63 

25.57 

20.33 

28.08 

22.93 

10.86 

14.21 

20.95 

12. 8u 

24 43 

31.52 

44.02 

50.64

12.57 

4.71 

10.12 

2.63 

15.76 

14.11 

31.20 

37.38 

50. S6 

50.54 

81. 36 

48.93 

72.56 

9.57 

68.98 

83. 71 

67.34 

73.74

52.90 

4.90 

2.00 

2.36 

16.50 

52.78 

14.23 

42.04 

40.47 

58.04 

74.22 

63.21 

27.93 

56.12

M-W 

mm.

28.26 

10.71 

23.83 

7.85 

49.20 

83.73 

83.78 

81.33

23.66 

48.89 

22.40 

38.48 

4.10 

4.70 

47.65 

67.67 

54.30 

63.30 

65.23 

58.21 

53.90 

46.83 

75.31 

51.79 

50.51 

56.86 

65. 71 

62.92 

62.25 

64.99 

73.72 

82.31 

72.54 

64.46 

44. 83 

36.48

65.48 

57. 67 

73.97 

49.84 

67.70 

66.32 

55.88 

53.70 

44.48 

43.80 

9. 14 

39.60 

14.13 

70.72 

26.11 

10.81 

27.64 

7.51

38.46 

48.89 

63. 39 

89.76 

52.12 

45.55 

56.84 

44.49 

52.64 

25.79 

10.01 

8.84 

51.06 

40.10

M-M« 

mm.

6.59 

.76 

1.83 

4.02 

15.90 

7.79 

8.54 

8.33

76.07 

46.69 

.25 

8.17 

.71 

.32 

49.88 

27.60 

33.46 

27.05 

23.76 

30.25 

21.82 

44.43 

10.71 

35.53 

20.50 

19.97 

5.53 

12.48 

24.72 

19.23 

3.78 

4.52 

2.52 

3.83 

10.94 

11.15

21.42 

37.29 

14.20 

46.74 

16.34 

18.41 

11.89 

7.15 

3.98 

4.69 

.13 

1.60 

.22 

12.44 

.82 

.39 

.40 

.56

3.05 

40.16 

34.15 

7.84 

29.20 

1.61 

25.48 

5.57 

2.11 

9.74 

.93 

.75 

16.34 

2.34

Geologic 

formation

Wilcox. 

Do. 

Do. 

Do. 

Do. . Do. 

Do. 

Do.

Recent. 

Do. 

Do. 

Do. 

Do. 

Do. 

Sparta. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do.

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Wilcox. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do.

Recent. 

Sparta. 

Do. 

Do. 

Do. 

Do. 

Do. 

Wilcox. 

Do. 

Do. 

Do. 

Do. 

Do. 

Do.
210 CONTRIBUTIONS TO HYDROLOGY, 1944

TABLE 5. Mechanical analyses of sand samples from wells in the Natchitoches area

Louisiana Continued

Well No.

25~(Na-58) Con. 

28 (Na-61) ........

Depth of 

sample 

(feet)

688-699 

708-712 

712-722 

732-749 

749-770 

770-782

208-217 

217-229 

229-239 

239-250 

250-260 

309-323 

501-511 

535-545 

545-550 

706-716

Mechanical analysis of sand fraction 

(percent by weight)

8-4 

mm.

4-2 

mm.

.13 

.19

.08 

.36

.11

.20 

.39 

.44

2-1

mm.

.34 

.94 

1.71 

1.07 

1.18 

1.37

.19 

.07 

.82 

.03 

.15 

.01 

.14 

1.04 

1,46 

1.70

1-1 H

mm.

2.36 

4.30 

6.38 

3.49 

3.55 

4.05

.39 

.86 

5.09 

3.75 

33.87 

3.84 

.63 

8.65 

11.85 

4.88

H-W 

mm.

14.42 

13.64 

18.01 

10.07 

24.27 

21.88

22.01 

65.08 

53.56 

91.16 

30.78 

31.85 

17.67 

60.52 

63.46 

32.33

H-M 

mm.

69.73 

54.39 

54.01 

46.20 

55.56 

53.49

58. 55 

33.19 

34.06 

4.99 

30.58 

42.39 

37.32 

26.83 

21. 15 

45.56

*i-Me 

mir.

13.15 

26.60 

19.70 

39.17 

15.36 

18.85

18.86 

.80 

6.36 

.07 

4.62 

21.91 

44.24 

2.76 

1.69 

15.09

Geologic 

formation

Wilcox. 

Do. 

Do. 

Do. 

Do. 

Do.

Sparta. 

Do. 

Do. 

Do. 

Do. 

Do. 

Wilcox. 

Do. 

Do. 

Do.
INDEX

Page 

Acknowledgments for aid ............ 160

Artesian water, occurrence ............... 168,176

Bentley formation, occurrence---....-....._ 181

Cane River formation, character and waterbearing properties.--..__.__ 177

Claiborne group, character and water-bearing

properties....-- 168,173-174,177-181,182

Cockfield formation, character and waterbearing properties.......... 168,181,182

Cook Mountain formation, character......... 179

fossils in............... .............. 179-180

Dickey, P. A., quoted........................ 164

Drillers' logs, value........................... 162

Drill-stem tests, method of making,. _.. __ 166

Electric logs, interpretation of. _.__._ 165-166 

method of making.-.-....----..-.--__ 163-165 

value______ ______---._____-____.. 162

Electrical resistivity, measurement of__--- 164-165

Eocene formations, character and waterbearing properties..._ 167-169,174-181

Exploratory program, benefits of....... ___ 167

purpose and scope...........-.-......., 159-160

Faults, effect of, on chemical character of

water.. --.. - 173,176-177

occurrence. __ ___ _._____..._ 169-172,176

Foraminifera, list of....-..--.-._...__..... 180

Fossils, list of.-.._--.--...-...---..----....-- 180

Foster, analyses by._..........._......__ 190

Gas, occurrence._....._.....__..._ 171,176

Geologic formations, water-bearing properties. 168,

175,176,177,178,181,182-184

Geology of the area..........____ 167-173, pi. 3

Hastings, W. W., analyses by............._ 190

Howe, H, V., fossils identified by__...._ 180

quoted......___......_.__........ 169

Location of the area..............._..._ 167,169

Page

Milams member of Cook Mountain formation, fossils in........ ..... 179-180

Miller, L. W., analyses by...._...__.._ 190

Montgomery formation, occurrence__.--..- 181

Oil, occurrence...______________.. 169 

Ostracoda, list of...__________.___ 180

Pleistocene deposits, character_._......... 181

Prairie formation, occurrence..____...__ 181 

Purpose and scope of the investigation__.. 159-160

Recent alluvium, character and watBr-bearing 

properties.----.----.---.-.-.---.__. 174,181-182

Red River Valley, features of. -------------- 167,168

Reeside, J. B., Jr., quoted.............__... 180

Rowley, J. H., analyses by.....______.. 190

Salt water, occurrence..._ 169,171,172,173,176,182 

Sampling, methods.__..__...______. 162 

Sand, mechanical analyses of.._...___. 208-210 

Self-potential, measurement of-------------- 163-164

Sibley Lake, origin_.....__________. 172

Sparta sand, character and distribut'on...__ 177-178 

water in... . 168,173-174,178-179,182

Spooner, W. C., quoted--- ._ 177-178 

Stratigraphy of the area..------- _.. 168,185

Structure of the area.-.-.-..._.......__ 169-173

Tertiary rocks, character and occurrence_.. 167 

Test holes, method of drilling...__.___ 160,162

Water, analyses of....--_..-_....---.-_-.- 190

quality of.... - 173-174,176-177,179,181,182,183

Wells, location..-------.-----------.__.... 161

logs of _ 191-208

recommendations regarding- .._ 182-184 

records of---- .- ._. ... _ 186-189

sand from, analyses of..._____.._ 208-210

water from, analyses of-.________ 190

Whale, fossil...--.--.....-. .. -..... 179,180

Wilcox formation, character and distribution... _ 174-176

water in.. 168,173-174 175,176-177,182 

Williana formation, occurrence......__... 181

211