DBPAETMENT OF THE INTEBIOK

BULLETIN

OF THK

UNITED STATES

GEOLOGICAL SUEVEY

2SCo. 133

WASHINGTON

GOVERNMENT PRINTING OFFICE

1896

UNITED STATES GEOLOGICAL SUEYEY

CHARLES D. WALCOTT, DIRECTOR

THE

DISSEMINATED LEAD OKES

AETHUE WINSLOW

WASHINGTON

G-OVERNMENT PRINTING OFFICE 

1896

CONTENTS.

Pas;e.

Letter of transmittal......................................................... 7

Location and area............................................................ 9

History of mining........................................................... 9

Topography ................................................................ 10

Stratigraplly and litliology.................................................. 11

Archean .......... ..... r.... ............................................ 11

Iron Mountain conglomerate............................................. 12

La Motte sandstone..................................................... 12

St. Joseph limestone.................................................... 14

Potosi limestone........................................................ 17

Structure................................................................... 18

The mines.................................................................. 20

Bonne Terre mines.................................I.................... 20

Flat River mines.....:........................................ .......... 21

Doe Run mine...... .................................. .................. 24

Mine La Motte.......................................................... 24

Avon mines....................... . ..................................... 25

General distribution of the ore.......'....................................... 25

The ore bodies.............................................................. 28

Index...... ................................................................ 31
ILLUSTRATIONS.

PLATE I. Geological map of the disseminated lead ore subdistrict of southeastern Missouri............................................... 8

II. Cross-sections to accompany the geological map.................. 10

III. Map and cross-sections of the Bonne Terre mines................. 20

IV. Map and cross-sections of the Flat Kiver mines................... 22

V. Map and cross-section of the Doe Run mine. ..................... 24

VI. Map and cross-sections of the Mine La Motte .................... 26

FIG. 1. Diagram illustrating conditions of sedimentation .................... 18

2. Diagram illustrating conditions of sedimentation.................... 19

3. Cross-section through drill holes at Doe Hun shaft................... 22

6
LETTER OF TRANSMITTAL.

ST. Louis, Mo., May 27,1895.

SIR : I have the honor to transmit herewith my report on the disseminated lead ores of southeastern Missouri.

The results contained in this report are the product of investigations 

conducted during the past three months. These investigations were in 

extension of the work on which was based my report, as State geologist of Missouri, on the lead and zinc deposits of the whole State. The 

principal contributions which the present report makes to our knowledge of the district relate to the structure and the general areal geology. 

The outlines of the formations as represented on the map have never 

before been denned, and the structure as recorded in the drill-hole 

results and expressed in the cross-sections has never before been presented. In addition, the most recent progress in mining is recorded, 

and the general distribution of the ore as revealed by drilling is outlined.

In order, however, that the report may stand by itself as a short 

treatise on this important lead district, I have not restricted myself to 

the mere presentation of that which is new, but have rounded this out 

with brief descriptions abstracted from my recently published report 

above referred to. Much local detail there included, however, is here 

omitted, and for such supplementary matter the reader is referred to 

that report.

In conclusion, I desire to express my indebtedness for assistance in the 

prosecution of the work, and for information contributed, to Mr. Arthur 

Thacher, superintendent of the Central mine; Mr. O. M. Bilharz, assistant superintendent of the Doe Bun mines; Mr. Frank Schulte, of Fredericktown; Mr. George J. Cole, secretary of the Derby Lead Company; 

Mr. D. Bauman, of Farmington; and ex-Governor H. C. Brockmeyer, of 

St. Louis. *

Very respectfully, your obedient servant,

ARTHUR WINSLOW. 

Hon. CHARLES D. WALCOTT,

Director United States Geological Survey.

1

U.S.GEOLOGICAL SURVEY. BULLETIN NO. 132 PL.I.

GEOLOGICAL MAP

OF THE

SOUTHEASTERN MISSOURI 

DISSEMINATED LEAD ORE SUB-DISTRICT

BY 

ARTHUR WINS LOW

1895.

/V.37 !.

N.36 I

35/V.

LOWER SILURIAN.^

LEGEND C

PO 1 POTOSI LIMESTONE .

S [ STJOSEPH LIMESTONE

I M LA MOTTE SANDSTONE.

~e [GRANITE.

P | PORPHYRY.

 SHAFT.

o DRILLHOLE.

 PIT

n BUILDING. '

O 0. DEPTH OFORILLHOLE.

O A. ALTITUDE OF SURFACE.

OSS. ALTITUDE OF SANDSTONE.

O G. ALTITUDE OF GRANITE. '

O P. ALTITUDE OF PORPHYRY.

33/V.

Scale.

Lith.A.Hoen iCo.Baltimore.
riun ADflO AU LMU Ditto Or

BY ARTHUR WINSLOW.

LOCATION AND AREA.

The disseminated lead ores of Missouri are encountered within 60 

miles south of St. Louis and within 25 miles west of the Mississippi 

Kiver. They belong to the southeastern lead and zinc district of the 

State. The area in which these ores have been developed is about 35 

miles long in a northerly-southerly direction and about 25 miles broad 

from east to west; it lies principally in St. Frangois County, but the 

northern portion of Madison County and a little of eastern St. Genevieve County are included. Only 13 mines have been opened in these 

ores; the mines are somewhat widely separated, and may be grouped 

into four camps, as follows:

At Bonne Terre: The St. Joseph Lead Company's mine, five separate openings.

In the Flat River camp: The mine of the Desloge Consolidated Lead Company, 

 including two openings; the Taylor mine of the Flat River Lead Company; the mines 

of the Doe Run Lead Company, including two openings; the mine of the Central 

Lead Company; the Crawley shaft of the St.Joseph Lead Company; the Donnelly Lead Company's mine; the Leadington Lead Company's mine; and the Derby 

Lead Company's shaft, which is now being sunk.

At Doe Run: The Doe Run Lead Company's mine. 

. At Mine La Motte: The mine of the Mine La Motte estate, four separate openings.

In addition, the diggings at Avon may be included.

Other ore bodies have been exploited by drilling, and numerous occurrences of sparsely disseminated ores have been revealed, but there are 

also great areas which are practically barren.

HISTORY OF MINING.

Lead mining in southeastern Missouri has been in progress nearly 

two hundred years, beginning about 1720. But the mining of disseminated ores on the scale now seen is of recent date, beginning scarcely 

thirty years ago. It is true that before the middle of the eighteenth 

century disseminated lead ores were dug at Mine La Motte, but they 

were difficult to work and smelt, and preference was given to the 

massive galena found in surface clays and in crevices in the rock. 

Featherstonhaugh T describes the quarrying here of disseminated ore

1 Geological Keport of the Examination made in 1834 of the Elevated Country between the Missouri 

and Bed Elvers, Washington, 1835.

9
10 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

in 1836. Up to 1878, however, the mining of this deposit was crude 

and interrupted, the excavations consisting of pits in the loose surface 

materials or of shallow shafts sunk to- strike the ore in the rock immediately beneath the surface.

Austin, in 1804, refers to a find of galena in small particles in a soft 

gray limestone on Big Eiver. At the Avon mines work was begun 

about 1848, and was sustained for a few years. After a long in.termission operations were resumed in 1874, but the mine was soon after finally 

abandoned. The whole output is reported to have amounted to about 

1,200 tons of ore. Shortly before the war, at the site of Bonne Terre, 

Francis LaGrave found, with a churn drill, disseminated lead ore at a 

depth of 80 feet.

But the beginning of the present mining era was essentially postbellum. In 1864 the St. Joseph Lead Company acquired possession of 

its Bonne Terre lands and began preparations for systematic mining. 

During the first few years there were many obstacles to overcome, and 

the production up to 1870 did not amount to much over 1,200 tons of 

lead. The diamond drill was introduced here in 1869 and did much to 

advance operations. By 1874 the annual output had reached 1,300 tons 

of lead, and many improvements had been made. Now the annual production of this company is nearly 15,000 tons of lead ; a large concentrating plant with a capacity of 1,000 tons of rock per twenty-four 

hours is in operation, together with smelting works at Herculaneum, a 

supplementary railway 50 miles loug, and other incidental establishments.

At Mine La Motte systematic work was begun after 1878; deep shafts 

were sunk, and since then a concentrating mill and furnaces have been 

erected. About one-third of the total output has been mined since that 

date.

The Doe Eun deposit was the next in order of development; but 

the first prospect shaft was not sunk there until 1885. Within two 

or three years after that date the mine was opened and the mill and 

furnaces were erected.

The Flat Eiver mines were the last opened in disseminated ores. 

Most of the diamond drilling has been done since 1888, and there was 

no deep shaft operating these ores before 1890, though a large number 

had been sunk for crevice mineral, and on the present Desloge property 

the old Bogy shaft, sunk in the early seventies, reached a depth of 

about 220 feet. Practically all of the developments of this camp have, 

therefore, been made during the last five years.

TOPOGRAPHY.

The topography of the country in which the disseminated lead ores 

are found is hilly, but not mountainous. The writer has described it as 

intermediate between the highland type of the Archean area which 

flanks it on the southwest and the plateau type which prevails in south-
U.S.GEOLOGICAL SURVEY. BULLETIN NO. 132 PL.

AX

BOO'- 

600-

LEGKND.

PORPHYRY

CROSS SECTIONS

TO ACCOMPANY

GEOLOGICAL MAP OF SOUTHEASTERN MISSOURI

ARTHUR WINSLOW

Scale.

Lith.A.Hoen S-CaBallimore
WINSLOW.] STRATIGRAPHY AND LITHOLOGY. 11

western Missouri, where there are deep valleys between flat uplands 

or long, level-crested ridges. Occurring in a country of nearly horizontal 

strata, the forms and distribution of the features of relief have no 

marked relation to geologic structure; they are of irregular distribution 

and of widely varying shapes and dimensions. The extremes of altitude, excluding the Archean hills, are 1,200 and 600 feet above tide, 

while locally the tops of the hills are generally not more than 200 feet 

above the valleys.

The hills are mostly covered with timber, principally oaks, of medium 

or small size and of little value except for local uses.

The larger streams have narrow flood-plains which are cultivated, 

but the farming lands are generally over the minor hills and slopes 

lying between the streams and the summits.

STRATIGRAPHY AND LITHOLOGY.

The rocks of this portion of southeastern Missouri belong to the following formations:

f

Potosi limestone. 

St. Joseph limestone. 

La Motte sandstone. 

Iron Mountain conglomerate. 

Archean.......... Granites and porphyries.

The distribution of these formations is shown on the accompanying 

geological map (PI. I). The clastic rocks are placed in the Lower Silurian for reasons given in detail in the writer's recent report on the lead 

and zinc deposits of Missouri. 1 The possibility still remains that there 

may be a faunal break which will admit of some of the lower strata 

being classed as Cambrian, though there is nothing in the stratigraphy 

to suggest it. This must, therefore, be left to the paleontologists, and 

owing to the great dearth of fossils the problem is not an easy one for 

them to solve.

ARCHEAN.

The Archean rocks undoubtedly underlie the whole country, but 

they crop out within the mining area only in the vicinity of Mine La 

Mo'tte. Southwest of that mine is the border of the main Archean 

area of the State, as shown on the map. Outliers are found on the 

eastern margin of the area mapped, in St. Genevieve County, but these 

are really beyond the limits of the disseminated ores as here defined. 

We have, hence, little to do with these rocks; their connection with 

the ore deposits is of but a general nature. The only localities where 

they are in close association are at Mine La Motte and at Doe Eun.

The porphyries are generally red or brown, and are composed principally of quartz and feldspar, with small grains of iron oxide scattered 

through the ground-mass. The texture is fine-grained and homogeneous, 

and, under the microscope, is holocrystalline; larger porphyritic crystals 

of quartz or feldspar occur scattered through the base. The wavy lines

1 Missouri Geological Survey, Vol. VI, 1894, Lead and Zinc Deposits, Chap. IX.
12 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

known as " flowage structure" are also present. The rock is frequently 

brecciated, the fragments themselves being composed of porphyry.

The granites are mostly of a pink color. The constituent minerals 

are principally quartz and feldspar. Black mica occurs in a few places, 

but it is not evenly disseminated. Hornblende is very rarely found. 

In texture the granites,, frequently approach the porphyritic, the feldspar occurring as a ground-mass in which the quartz crystals are embedded. In other cases the constituent crystals of quartz and feldspar 

are clearly separable, and occur in nearly equal proportions.

Eegarding the relations of the granites and porphyries, the conclusion 

has been reached by Mr. Haworth that they were " formed from the 

same or similar molten magmas, and that their differences in texture 

are probably due to their solidifying under different physical conditions, 

and, secondarily, to a slight lack of homogeneity in the magmas."

IRON MOUNTAIN CONGLOMERATE.

This formation, which derives its name from its development at Iron 

Mountain, in association with the iron ores, is of very irregular distribution, consisting of bowlders and large pebbles of Archean rocks occupying depressions and hollows in the old land surface. It is encountered 

underground in the workings at Doe Run; but it is often absent, the 

La Motte sandstone then resting directly on the crystallines. Outcrops 

have nowhere been observed within the area under consideration, and 

hence the formation is not shown on the map. Its thickness is very 

variable, attaining perhaps 50 or 100 feet in places, and from that 

dwindling down to nothing. In all probability the deposit never 

extended far from the shore-line. At Doe Eun the bowlders and pebbles consist of granite and diabase, while the matrix is principally 

limestone, which often is very chloritic and contains disseminated 

galena. The rock lies in depressions of the granite floor or massed 

against steep walls.

LA MOTTE SANDSTONE.

This rock underlies nearly the entire area represented on the map, 

but is exposed only around the Archean outcrops where it extends up 

the old hillslopes and over the eastern portion, in St. Genevieve 

County, where the Farmington anticline brings it to the surface. In 

St. Genevieve County it was described by Shumard as the Second Sandstone, and, strange to say, was placed over the St. Joseph limestone to 

the west, which was classed as Third Magnesian.1 Preconceived ideas 

probably prejudiced observation, and further, as the field work was in 

St. Genevieve County and proceeded from east to west, the sections 

bes't displaying the relations of these formations were probably not 

examined. Had the geology of St. Framjois County been carefully 

studied the mistake could not have been made.

>Keport Missouri Geologial Survey, 1855-1871, p. 299.
STKATIGRAPHY AND LITHOLOGY. 13

The thickness of this formation within the mining area is very variable; it tapers out up the slopes of the old Archeaii hills, while in closely 

adjoining depressions it may be 200 feet thick. Thus, at Mine La 

Motte it has been drilled into to a depth of 250 feet and the bottom not 

reached. Near the southeastern end of Sirnins Mountain a shaft was 

sunk in it to a depth of 100 feet. These are both in proximity to Archean 

outcrops. The thickness away from such, in the larger basins, has not 

.been determined. It probably amounts to as much as 400 feet, if not 

more.

The distribution of this sandstone was, apparently, largely determined 

by two conditions, i. e., the proximity of granite and the slope of the 

Archean floor. Porphyries have very little free quartz, and consequently sandstones are not readily derived from them. Granites abound 

in free quartz, and must be regarded as the principal sources of supply.

Heuce we find the La Motte sandstone in greatest abundance about the

granite areas. Where the slopes from the old shore-line were steep 

sandstone sediments could not gather, but sank to the basins, and in 

such cases were completely covered by the later-formed limestones.

ThivS sandstone generally occurs in thick, massive beds, though it is 

sometimes thinly bedded or flaggy near the top. Jt is usually composed 

of grains of quartz in a matrix of smaller quartz grains. Sometimes the 

matrix is limy, and at the top of the formation the rock grades into a 

sandy limestone, and beds of limestone alternate with beds of sandstone. 

Near the base it is often of coarse texture, containing layers of grit and 

small quartz pebbles; also decomposed porphyry and granite, and pebbles of those rocks when near Archean areas. It sometimes contains 

chlorite, but is never micaceous. It is usually soft and friable, and often 

false bedded. The color is generally yellow or reddish, sometimes white. 

The quartz grains are often enlarged secondarily, but not always.

The following are illustrative sections of this formation:

Record of drill hole No. 211, Mine La Motte.

Feet.

1. Surface clay................................................................ 13

2. Limestone, white, sandy...................... .............................. 2

3. Sandstone, black, yellow, and white........................................ 10

4. Sandstone, white........................................................... 12

5. Sandstone, yellow................. ............................_....._...... 28

6. Sandstone, white and yellow beds .......................................... 178

7. Sandstone, pink............................................................ 21

8. Sandstone, almost red....................................................... 9

Total..................................................................... 273

Record of drill hole No. 51C, Bonne Terre.

Feet.

1. Limestone, no core, drilled with a solid bit.................................. 277

2. Limestone, magnesian, coarse-textured, crystalline, with galena disseminated at intervals and also lining small cavities; a good deal of chlorite; 

no chert.................................................................. 60

3. Limestone, like above, more dense, highly chloritic, somewhat shaly; some 

galena................................................................... 5
14 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

Feet.

4. Shale, dark and drab colored; a little galena near the base.................. 4

5. Limestone, magnesian ...................................................... 5

6. Limestone, sandy, very granular, pitted, highly chloritic; little galena, with

pyrite disseminated in small grains....................................... 9

7. Sandstone, like the last, less chloritic, more sandy, containing not much more

than enough lime to cement the grains together.......................... 8

8. Limestone and sandstone, consisting of alternations of sandy magnesian limestone and of limy sandstone; white and drab; in part coarse and granular, 

elsewhere dense and shaly, but always sandy; little chlorite; some pyrite 

at 411 feet; no galena; limestone less porous than higher up.............. 86

9. Sandstone, brown to red, soft, friable; grains rounded and not enlarged secondarily; containing little or no lime, but with a matrix of very fine sand. 20

Total..................................... .............................. 474

Record of shaft at foot of Simms Mountain, middle of N W. J sec. 36, T. 36 N., R. 4 E.

	Feet.

1. Soil and clay.............................................................. 5

2. Sandstone, yellow......................................................... 2

3. Sandstone, blue......................... .................................. 8

4. Sandstone, yellow......................................................... 12

5. Sandstone, gray, with porphyry pebbles................................... 3

6. Sandstone, blue................. .......................................... 5

7. Sandstone, gray, with hard granite pebbles................................ 10

8. Sandstone, white.......................................................... 20

9. Sandstone and conglomerate, with sandstone pebbles ....................... 7

10. Sandstone, white .......................................................... 22

11. Conglomerate, with granite or porphyry .................................... 1

12. Granite, red, with upper 9 feet soft, lower 3 feet hard....................... 12

Total................................................................... 107

Record of drill hole No. 9, Series II, Doe Run.

Feet.

1. Surface clay ............................................................... 49

2. Limestone, gray............................................................ 89

3. Sandstone ................................................................. 56

4. Limestone, gray.... .......±.................... ............................ 8

5. Sandstone .................................................................. 5

6. Decomposed granite and limestone ......................................... 4

7. Granite,hard .............................................................. 5

Total................................................................... 216

ST. JOSEPH LIMESTONE.

This formation also underlies the larger part of the area, and is the 

prevailing surface rock. Like the Mine La Motte sandstone, it also 

wedges out up the old hillslopes, and in shallow basins it is of much 

diminished thickness. Thus, just north of Knob Lick the Potosi limestone is almost, if not immediately, in contact with the La Motte sandstone, because of the nearness of the granite floor to the surface. At 

Mine La Motte the thickness from the sandstone to the overlying 

Potosi limestone is estimated to be about 200 feet, while around Flat
WINSLOW.] STRATIGRAPHY AND LITHOLOGY. 15

Eiver and Bonne Terre it is somewhere near- 600 feet, which is probably about the maximum.

This limestone occurs normally in massive beds, but it is sometimes 

thinly bedded and flaggy, especially near the base as exposed along the 

eastern edge of St. Frangois County, and also in the upper part as 

exposed along Flat Eiver. Shale beds are also included; such are 

encountered near the base of the section at Mine La Motte, near the 

base and top at Bonne Terre, and in the upper part along Flat Eiver 

and southward to the St. Frangois Eiver. They seem at places to be 

quite widespread, and elsewhere very. limited. They are of blue and 

greenish colors.

The texture of the St. Joseph limestone is normally granular, the 

rock consisting of closely compacted crystals of dolomite, sometimes 

mixed with calcite. It is often minutely vesicular, with dolomite crystals lining the cavities. Sometimes it is fine-grained, The color is

light or dark gray, the latter particularly in the ore-bearing portions; 

on weathering, the rock often acquires a yellow color.

In composition it is a limestone with a large percentage of magnesia, 

though generally less than in a theoretical dolomite. It contains more 

or less silica, especially near the base, where grains of sand are visible 

and the rock grades into a sandstone. It also often contains much 

chlorite, in places sufficient to give the rock a decidedly green color. This 

mineral is especially abundant in the exposed lower beds of eastern 

St. Frangois and of western St. Genevieve counties, and the drill cores 

show it to be prevalent in the basal beds along Flat Eiver. No chert or 

drusy quartz is found in this formation.

Typical sections of this formation are as follows:

Record of drill hole No. 93, Mine La Motte. Feet.

1. Clay......................................................................... 8

2. Limestone, yellow.......................................................... 5

3. Limestone, gray............................................................. 106

4. Limestone, gray, pink, white, and black alternating........................ 64

5. Limestone, black........................................................i... 96

6. Slate and sand, dark ....................................... ..^............. 5

7. Limestone, gray.................................. .......................... ' 3

8. Sandstone, white .......................................................... 3

Total.........................-.-........-.................;............ 290

Record of drill hole No. 530, Mine La Motte.

Feet.

1. Clay....................................................................... 8

2. Limestone, lower part slaty ................................................ 14

3. Limestone, black........................................................... 44

4. Limestone, gray and white ................................................. 8

5. Limestone, " Black," with galena .......................................... 38

6. Limestone, gray and black ................................................. 5

7. Limestone, " White," with galena.......................................... 45

8. Sandstone.................................................................. 8

Total................................................................... 170
16 LEAD OJSES OF SOUTHEASTERN MISSOURI. [BULL. 132.

Record of drill hole No. 46, Bonne Terre.

i Feet.

1. Soil and clay.............................................................. 9

2. Limestone, brown......................................................... 51

3. Limestone, black.......................................................... 13

4. Limestone, with specks of. galena.................... ...................... 9

5. Limestone, yellow..."...................................................... 14

6. Limestone, dark and light colored layers alternating ...................... .51

7. Limestone, black.........................................................:. 10

8. Limestone, with a little galena............................................ 11

9. Limestone, with a seam of calcite ......................................... 14

10. Limestone, with a little galena............................................ 10

11. Limestone, showing a seam of galena...................................... 9

12. Limestone, rich in galena................................................. 5

13. Limestone, with little galena.............................................. 9

14. Limestone, dense, hard.................................................... .42

15. Shale..................................................................... 15

16. Limestone, hard, white.................................................... 10

17. Limestone, dark-colored and softer........................................ 36

18. Limestone, porous, much chlorite........................................... 1

19. Limestone, with disseminated galena...................................... 3

20. Limestone, a little galena and chlorite...................................... 30

21. Galena, rich............................................................... 1

22. Limestone, little galena................................................... 18

23. Limestone, no galena, very green.......................................... 32

24. Soft clay and brown rock.................................................. 2

25. Limestone, very green, with white spots like marble........................ 14

26. Sandstone ................................................................ 19

Total................................................................... 441

Record of Italian drill hole No. 2, Bonne Terre.

Feet.

1. Limestone, shaly........................................................... 17

2. Limestone, buff-colored..................................................... 143

3. Limestone, grayish, some shale.................................. ........ .... 140

4. Limestone, gray, shaly near bottom........................................ 93

5. Limestone, considerable chlorite............................................ 11

Total................................................................... 404

Record of drill hole No. 2, Central Lead Company.

Feet.

1. Surface clay............................................................... 4

2. Limestone, yellow and variegated......................................... 106

3. Limestone, gray...... .................°................................... 55

4. Limestone, gray, with some specks of galena and 2 inches of richly disseminated ore at base........................................................ 15

5. Limestone, gray, with small specks of galena.............................. 40

6. Limestone, gray, with galena in seams..................................... 126

7. Limestone, gray, with seams of shale and disseminated galena............. 8

8. Limestone, gray, Avith seams of shale, and rich in galena................... 2

9. Limestone, dark, coarse texture, rich in galena ....................;........^ 14

10. Limestone, light color, coarse texture, some galena........................ 4

11. Limestone, sandy, white, no galena. ................^.............. ........ 4

Total................................................................... 378
WINSLOW.] STRATIGRAPHY AND LITHOLOGY. 17

Record of drill hole No. 1, on the Mitchell land: S W, corner of SE:$ sec. 29, T. 36 N.,B,5 E.

Feet.

1. Limestone, cherty .......................................................... 105

2. Shale or "slate"........................................................... 247

3. Limestone, no chert........................................................ 120

Total (hole abandoned at this depth).................................... 472

Record of drill hole No. 2, on the Hunt land: NE. \ of NE. J sec. 82, T. 36 N,, E. 5 E.

Feet.' 

.- Rhale and limestone, no chert............................................... 200

2. Limestone ................................................................. 280

3. Limestone, with galena..................................................... 135

4. Sandstone.

Total ................................................................... 615

In the holes sunk on the Derby Lead.Company's land and vicinity, 

Mr. George J. Cole reports that shale or slate, interspersed with layers 

of limestone, from 144 to 160 feet thick in all, was encountered.

POTOSI LIMESTONE.

The rocks of this formation are found principally west and north of 

the area here treated of, and they occur within it only over the hills. 

The upper limits of the formation are, therefore, not reached, and it is 

probable that no sharp line°of separation between it and the underlying St. Joseph limestone exists; hence the full thickness can not be 

given. At Mine La Motte Mr. Mills has placed the thickness of his 

11 cherty " limestone which is essentially the same as the Potosi at 270 

feet, and this is probably as great a thickness as it attains anywhere 

within the limits of the area shown on the accompanying map.1

These limestones are essentially the same as those of the St. Joseph 

formation, the difference between the two formations being in the prevalence of chert and drusy quartz in the Potosi. These are found principally in a residuary form, scattered through the clays and other materials 

which cover the surface; but they are also found in the rock, though 

not so abundantly as the profusion over the surface might lead one to 

expect.

Two principal forms of chert are distinguishable, the one dense, 

intensely hard, nearly white, with a conchoidal fracture, in appearance 

not unlike some varieties of porphyry, sometimes found in blocks 6 

feet and more in diameter; the other, the drusy quartz known as "mineral blossom." The latter is found in great abundance over the surface 

in gnarled, irregularly shaped masses, both large and small; it consists 

of layers of amorphous chalcedonic silica covered with quartz crystals 

on the free surfaces. In the solid rock it is found lining cavities, in the 

forms of pipes and sheets; it is intimately mixed with the limestone, 

and was probably formed by a segregating action at an early stage in

* Geological Report on tihe Mine La Motte Estate, by James E. Mills, New York, 1877.

Bull. 132 2
18 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

the history of the latter. There is no direct connection between this 

rock and the occurrence of ore; their association is simply a coincidence, 

but it was seized upon by the early settlers as a possible suggestion, 

which has been handed down.

The way in which these residuary cherts are found over the surface 

leads to the conclusion that they are not uniformly distributed through 

the formation, but are segregated in patches of greater or less extent, 

and that they have a quite variable vertical as well as horizontal distribution. Moreover, these remains are so imperishable that they may 

cover the surface in great profusion long after all of the limestone in 

which they were contained has been disintegrated and removed. It is 

impossible in many instances to determine whether this is the case or 

not. Hence, in mapping the formation the best that can be done is to 

outline those areas over which the profusion of chert remains is so 

great, and the topographic conditions are such, as to warrant the belief 

that they are in place and not transported.

STRUCTURE.

The structure of the area is so simple, and is so clearly expressed in 

the geological maps and cross-sections, that little need be said here.

FlG. 1. Diagram illustrating conditions of sedimentation.

One controlling condition to be borne constantly in mind is that the 

sedimentary rocks have been laid down upon a very uneven floor, and 

in large part in quite shallow basins in which numerous islands of 

Archean crystallines occurred. This is especially the case over the 

southern portion, about Mine La Motte. Local inclinations of the rocks 

have thereby been produced which resemble dips caused by flexing, 

whereas they are in fact merely the results of sedimentation upon a 

, sloping floor. Another outcome of these preexisting conditions is a 

great variability in the character, and especially in the thickness, of 

the strata, and some anomalies in distribution arise. Thus the basal 

La Motte sandstone, clinging to the Archean floor, may extend much 

farther up a submerged hillslope than does the overlying St. Joseph 

limestone, and may hence be topographically much above the latter in 

closely adjoining localities, as is illustrated in fig. 1. Or, again, over a 

shallow marginal platform covered with the sandstone of shore origin 

the St. Joseph limestone may never have spread itself, but may have
W1NSLOW.] STRUCTURE. 19

been confined to the depths of the basin beyond, while the later-formed 

and higher Potosi limestone may extend over the platform and thus be 

directly in contact with the sandstone without any erosion period having intervened. This is illustrated in fig. 2. Other combinations will 

suggest themselves without further elaboration, and the observer must 

be constantly on guard lest they mislead him.

The general structure of the area is seen to be that of a great basin 

between the main Archean area to the southwest and the granite outliers of St. Genevieve County to the east. This depression may be in 

part a product of flexing, but it is to be considered in the main a basin 

of erosion dating from Algonkian or Cambrian time. The shape of this 

basin we have been able to define with some degree of accuracy from 

the results of deep drillings in search of ore. The distribution of these 

drill holes is shown on the geological map (PI. I), and in each case the 

altitude of the surface and of the underlying sandstone is noted. A 

study of these notes and of the colored cross-sections (PI. II) accompanying the map will reveal the fact that the trough, of the basin follows 

approximately a line running from the Derby shaft on Flat Eiver southFIG. 2. Diagram illustrating conditions of sedimentation.

ward to Delassus, and thence toward Knob Lick, where it is interrupted by the granite archipelago near that place, and apparently 

transferred northward so as traverse the northern part of the Mine La 

Motte estate. The bottom of this trough, or, more exactly, the surface 

of the sandstone along its axis, is about 250 feet above tide on Flat 

Kiver and south of there to the St. Francois Eiver. The deepest point 

known is in the northeast corner of the Mine La Motte estate, where 

the sandstone floor is only 90 feet above tide. Thence it probably 

deepens southeastward.

The only faults of magnitude which have been recognized traverse 

the Mine La Motte estate. Two have been located there, running parallel to each other in a northwesterly-southeasterly direction. Of these, 

the minor one, known as the Main fault, traverses the mines. It consists of a series of short throws, or step faults, aggregating within the 

limits of the map from 25 to 150 feet, increasing southeastward. It is
20 LEAD OKES OF SOUTHEASTERN MISSOURI. [BULL. 132.

described in detail in the report of the Missouri Geological Survey,1 and 

the description will not be repeated here. The other is much more extensive; the throw where it crosses Big Rock Creek is about 300 feet, and 2 

miles southeast of that point it is nearly 700 feet. Both of these faults 

are represented in the maps and cross-sections of the La Motte mine. 

It is probable that other faults will be located in the future, very likely 

continuations of those described; but even these the writer is inclined 

to ascribe more to the nature of the original floor and to the conditions 

of deposition than to movements of rupture. The Main fault is parallel 

to the axis of a local basin of which the granite walls are probably very 

steep; the consolidation of the sediments by pressure of overlying 

deposits would naturally cause a breaking and slipping of the beds 

along a line parallel to the unyielding walls. The other fault, north of 

the Main fault, is apparently parallel to and just beyond the edge of a 

platform of Archean rocks from which there is probably a steep slope 

of the old surface. This, together with the consolidation of the sediments, may have produced a fracture or series of fractures along this 

line. That the slopes of the Algonkian land surface were often very 

steep is evident in many places. The depth of the sandstone, as shown 

by the drill-hole notes, within a mile east of Simms Mountain is proof 

of this; .and, again, north of Flat Eiver, at the northern extremity of 

the mountain, a hole 550 feet deep did not reach the sandstone, though 

that rock crops out within 600 feet south, whence the slope must be 

at least 45°.

THE MINES.

A list of the mines in disseminated ores is given on page 9 of this 

report. On the accompanying mine maps (Pis. Ill to VI) an attempt 

is made to show their, exact locations and the extent of developments 

to date.

BONNE TEKRE MINES.

The St. Joseph Lead Company's mines are situated at Bonne Terre. 

Five separate openings may be distinguished. The first, worked by the 

main shaft and by a number of other shafts, is by far the most extensive. 

It is nearly three-fourths of a mile long and over half a mile wide. Five 

different levels are distinguished at depths of 80,118,158,205, and 230 

feet. Ore is found, thus, practically from the surface down to 250 feet; 

in fact, in the early'days of mining the disseminated ore was taken out 

here in an open cut. Shaft No. 4 is 280 feet deep and the workings are 

quite small, as is shown on the.map. Shaft No. 5 is 250 feet deep and 

only a small area has been mined out at the bottom. Shaft No. 6 is 218 

feet deep. The drift is at the bottom, and the excavation, though larger 

than that of Nos. 4 or 5, is still quite small as compared with the main 

mine. Shaft No. 7 is 330 feet deep. It is a new opening. Ore was 

found at a depth of 170 feet and was excavated for a distance of about

1 Vol..VIII, 1894, Lead and Zinc Deposits, p. 657.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 132 PL. in

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D = DEPTH 

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SHAFT 

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|'/£MILES
WINSLOW.] FLAT EIVER MINES. 21

50 feet on all sides of the shaft. Between this depth and the bottom, 

where drifts are now being started, more or less galena was found almost 

continuously. A drill hole sunk here to a depth of 407 feet did not reach 

the La Motte sandstone, but shale and chlorite were encountered at that 

depth, which indicate that the sandstone is not far distant. The sections given on pp. 13-14 illustrate the character of the rocks encountered 

here. In general, the upper hundred feet or so contain more or less shale, 

and the magnesian limestone is, in part, thinly bedded and flaggy; under 

this are some 200 feet of thicker-bedded, massive limestone, in which 

the ore occurs; below this, again, there is argillaceous shale for about 

30 'feet, followed by 100 feet or more of magnesian limestone, which is 

sandy to a greater or less extent and contains also some thin layers of 

shale; this is followed by the basal sandstone. As is shown on the 

cross-sections of the mine map (PI. Ill), the La Motte sandstone is at a 

depth of 400 or 440 feet beneath the surface, and appears to dip slightly 

southward. The production of the St. Joseph Lead Company during 

1894 amounted to 15,826 tons of lead; the total output from this camp 

up to the end of that year aggregated,^ round numbers, as much as 

215,000 tons of lead.

PLAT RIVER MINES.

The mines of this camp are all very recent openings, and the developments are consequently quite small. They bid fair, however, to attain 

the dimensions of the Bonne Terre mines before very long.

The Desloge Consolidated Lead Company's mine consists at present 

of three shafts, which are -located on the map. Of these shafts, No. 2 

is the only one worked as yet. Two runs of ore have been drifted on 

here. The bottom of the lower run is at a depth of about 320 feet, and 

the face of the drift is in places as much as 60 feet high. The upper 

run is between the depths of 190 and 270 feet. The sandstone is at 

about 380 feet, and some little galena is found between it and the lower 

level. Shaft No. 1 is the old Bogy shaft, and connects with No. 2 by a 

tunnel. Shaft No. 3 has just been sunk to a depth of nearly 300'feet, 

and will soon be operated. The rock passed through in these shafts is 

almost entirely limestone, little shale being noted. Much chlorite was 

found, especially in shaft No. 3. The sandstone floor is nearly horizontal. The mine is equipped with a large concentrating mill having 

a present capacity of 350 tons per day and an anticipated capacity of 

about double that amount. Four furnaces are in operation, and all the 

preparations are for a large output.

The Flat River Lead Company's mine, or the Taylor shaft, is yet in 

embryo. The shaft is 308 feet deep, and an incline extending thence 

200 feet northward reaches 23 feet deeper. The first ore was encountered at a depth of about 160 feet, and from there to the bottom disseminated galena was passed through at frequent intervals, in yellow, 

white, and gray limestone. No shale is recorded in the section of the
22 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

shaft. " Sandstone is reached in drill holes at a depth of about 425 feet. 

It is thus over 70 feet lower than at the Desloge shaft, and it must consequently rise in that direction. On the other hand, as will be seen 

later, the sandstone is here also about 50 feet lower than at the Crawley shaft to the east. Consequently, the Taylor shaft must be somewhere near the center of a basin. Much water has been encountered 

here, which has obstructed mining, and undoubtedly its central location 

in this trough is the reason for this, as the water comes from below.

FIG. 3. Cross-section through drill holes at Doe Run shaft.

The production of this mine in 1894 was 237 tons of lead, and its total 

production to date is 525 tons of lead.

The Doe Run Lead Company's mines, on Flat River, consist of two 

openings, numbered 1 and 2. No. 1 is now abandoned. The shaft 

was 380 feet deep, passing through gray magnesian limestone and frequent beds of shale. Only one run of ore was worked, and this was 

near the bottom of the'shaft. The flooding of the mine with water 

from a channel which runs near the southern edge of the workings 

caused the abandonment of this mine. Shaft No. 2 has been opened
U. S. GEOLOGICAL SURVEY BULLETIN NO. 132 PL. IV

LEAOIN<£TON LEAD Co

. 'jP*ffiK&m 

"QpNNELLY LEAD Co *Hs?i£g 5H"rT

THE FLAT RIVER MINES
WILLOW.] . PLAT RIVER MINES. 23

within the last two years. The depth to the bottom of the sump is 

nearly 460 feet, and no genuine sandstone was reached, though the 

green chloritic beds, which are close to thafrroek, were penetrated. 

Two runs of ore are distinguished one at a depth of 430 feet, the other 

at 403 feet. The lower run, so far as developed, varies in thickness 

from 1£ to 8 feet. The upper run is not quite so thick at the shaft, but 

drillings show an increase to the south. These conditions are, however, 

very variable, as is illustrated in the accompanying cross-section of 

drill holes here, kindly contributed by Mr. 0. M. Bilharz, the assistant 

superintendent. The ore, as taken out, contains about 170 pounds of 

galena to a mine car of rock weighing about a ton or less. The lower 

drift runs in a general northeasterly-southwesterly direction. Parallel 

to the workings on the south side is a crevice, or channel, from 5 to 40 

feet from the drift, with a course about east-northeast. The flow of 

water from this crevice was very heavy when it was first struck, but by 

tapping with drill holes and cautious cutting the water was drawn off 

without difficulty. Where cut at one point the crevice is about a foot 

wide, and a fault with an upthrow of about 15 feet on the south side is 

reported; beyond the crevice, however, drill holes show the ore body 

to be at the normal level, so that the effects of the faulting are not very 

persistent. Yellow clay and discolored, oxidized rock fragments were 

found in this crevice, indicating that it connects directly with the 

surface. The ore from this mine is shipped for treatment directly to 

the works of the company at Doe Bun. The shaft is well equipped for 

a large production.

The Central Lead Company's mine consists of one shaft 380 feet deep. 

The principal ore body is at the bottom, near the sandstone floor; it 

varies in thickness from a few feet to as much as 20 feet. Another run 

of ore was encountered at a depth of 240 feet, but it is of minor importance, and very little work has been done there. The sandstone is at 

a depth of about 390 feet, or at an altitude of 420 feet above tide; 

this is 100 feet above the bottom of the Doe Eun shaft No. 2, and 

consequently the slope of the sandstone must be quite steep between 

the two; possibly there is some faulting over and above that exhibited 

along the channel in the Doe Eun shaft, but there is no direct evidence 

of this. This mine is equipped with a good hoisting plant, shops, and 

a concentrating mill. It is producing now about 100 tons of concentrates per week, and the mill is being enlarged so that it will have double 

its present capacity. The production during 1894 was 1,719 tons of 

concentrates, averaging about 65 per cent of lead. The total production of the present company to the end of that year is 1,819 tons of 

concentrates. Crevices traverse the workings on the south side with 

nearly due east-and-west courses. They are not open, like the one 

encountered at the Doe Eun No. 2 mine, but are tight, knife edge-like 

seams, which are traced by the drip of the water along the roof and by 

occasional offsets in the rock of a few inches.
24 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

The Derby Lead Company's shaft is now being sunk, and is about 

120 feet 'deep. The intention is to sink it to a depth of 490 feet, which 

will be about 40 feet into the ore body. The sandstone is here at a 

depth of about 540 feet. Most of the lead ore encountered in the drill 

holes was through the lower 100 feet.

The Crawley shaft of the St. Joseph Lead Company is 365 feet deep, 

at which depth the sandstone was entered. An upper run of ore was 

encountered at 283 feet, and a drift about 100 feet long and 40 feet high 

has been driven in a northeasterly direction. A lower run of ore is at 

360 feet, and is about 20 feet thick; the drift at this level is only about 

30 feet long. A bed of pyritiferous limestone nearly 10 feet thick was 

passed through at a depth of about 173 feet. Very little pyrite is associated with the galena, however. A crevice,' or "channel," runs along 

the west side of the upper ore body parallel to the course of the upper 

drift. The output of the shaft is shipped directly to Bonne Terre for 

treatment, and is included in the productions of that mine.

The Donnelly Lead Company's shaft is 310 feet deep, and the sandstone is struck at about 320 feet. The run of ore, which is at the bottom 

of the shaft, is about 10 feet thick. A drift follows this in a northeasterly direction for about 260 feet ; a good deal of the cobalt-nickel sulphide, linnaeite, was found in this drift. The ground is traversed by a 

number of crevices running a little north of east across the drift. At 

a depth of 125 feet an upper and smaller run of ore was passed through, 

in which a good deal of pyrite was found. The mine is equipped with 

a small concentrating mill, and the product has been hauled in wagons 

to Flat Eiver. Only a small amount has been produced, however not 

more than 50 tons of concentrates.

The Leadiiigton Lead Company's shaft is 350 feet deep, and extends 

20 feet into the sandstone. About 250 feet of drift has been driven at 

the bottom. The ore body varies from 8 to 25 feet in thickness. The 

mine is not now operated. It is equipped with a concentrating mill, 

from which there were hauled in 1894 about 350 tons of concentrates,, 

and this is the total to date.

DOE RUN MINE.

The Doe Run Lead Company's mine at Doe Run is now almost idle. 

It was operated by two shafts, 47 and 110 feet deep, respectively. The 

ore was found principally between the depths of 50 and 90 feet. It 

lies very near the contact of the St. Joseph limestone with the Archean 

granite, and surfaces of the latter are exposed in the mine workings. 

The production of the Doe Run Company in 1894 amounted to 4,203 

tons of concentrates, which yield about 65 per cent of lead. Only about 

one-fourth of this was from the mine at Doe Run, the remaining threefourths coming from the company's shafts on Flat River. The total 

production of the company to the end of 1894 amounted to 21,300 tons 

of lead, of which nearly 5,000 tons came from the Flat River shafts.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 132 PL. V

A'ALTITUDE OF SURFACE

THE DOE RUN MINE

SS-ALTITUDE OF SANDSTONE G-ALTITUDE OF GRANITE = SHAFT

SCALE

O */4 >/z ^4. IMILE

DRJLL HOLE
WINSLOW.] GENERAL DISTRIBUTION OF THE ORE. 25

MINE LA MOTTE.

These deposits have been worked in many different ways. The earlier diggings consisted largely of open cuts. The principal underground developments of recent years have been at shafts Nos. 1 and 

2, which are about 110 feet deep; at shafts Nos. 3 and 4, about 125 

feet deep; at shaft No. 5, about 140 feet deep; and quite recently at 

shaft No. 6. These are located on the mine map (PI. VI) and have been 

fully described in the writer's report of the Missouri Geological Survey. 

Two ore horizons are recognized, belonging to an upper "Black rock" 

and to a lower "White rock." Their aggregate thickness varies from 

70 to 144 feet; they are sometimes separated by about 6 feet of gray 

limestone. The White rock is close upon the basal sandstone. The 

deposit occurs in a somewhat shallow basin between outcrops of granite, the axis of which pitches eastward.. A fault, or a series of slips 

accompanied by crevices, traverses or is contiguous to the workings of 

the shafts, excepting No. 6; it runs in a northeasterly-southwesterly 

direction. The mine is equipped with a good-sized concentrating mill 

and with furnaces for the reduction of the ore. The production for 1894 

was 2,626 tons of lead. The total yield of the Mine La Motte deposits 

to the end of that year was approximately 100,000 tons of lead.

AVON MINES.

The Avon mines deposit consists of galena in thin sheets and also 

disseminated in coarse sandstone, of which latter ore a bed about 2 

feet thick was seen by the writer in 1895. The deposit is represented , 

on the map as in the La Motte sandstone, but it belongs to the upperpart of that formation, where beds of magnesian limestone alternate 

with beds of sandstone. The top of the uppermost sandstone stratum 

is here taken as the dividing line.

GENERAL DISTRIBUTION OF THE ORE.

The ore bodies thus far developed are outlined by the various mine 

maps, but, beyond their immediate limits, further extensions have been 

proved in almost all cases by careful drilling. These holes are shown 

on the larger-scale mine sheets (Pis. Ill to VI), and toward them the 

workings are now being extended. In addition, much drilling for purposes of prospecting has been done away from the immediate vicinity 

of the mines. The distribution of the holes is indicated on the colored 

map (PI. I). People are naturally often reticent about divulging the 

results of such work, for manifest business reasons, and when results 

are given they must be accepted with a full ounce of precaution. The 

following brief notes are believed to be substantially correct so far as 

they go. They relate to different holes approximately located on the 

map:

West of the town of Bonne Terre, about 2 miles away, a number of 

drill holes have been put down by the St. Joseph Lead Company. Prom-
26 LEAD OEES OF SOUTHEASTERN MISSOURI. [BULL. 132.

isiug amounts of ore were found in these within the depths reached. 

About 1£ miles southwest of these is another drill hole, 320 feet deep, in 

which pyrite and a trace of galena were encountered at a depth of about 

100 feet.

South of Bonne Terre, between shaft No. 1 and Big Eiver, drilling has 

been done, and ore is reported to have been struck, but the results have 

not been obtained.

West of French Village, in one of the holes shown, about 3 miles away 

from that place, a little galena is reported to have been found, while the 

other holes were all barren. The holes were shallow, however, the deepest only about 265 feet deep, and none reached sandstone.

West of Flat Eiver, and within a mile south of Big Eiver, a number 

of holes have been put down. These are in the SE. ^ sec. 5 and the 

SW. J sec. 4, and in the SE. £ sec. 4, the south part of sections 3 and 2, 

and over adjacent grounds. Galena is reported to have been found in 

paying quantities in holes put down by the St. Joseph Lead Company, 

by H. C. Brockmeyer, and others. The maximum depth was about 510 

feet and reached chloritic limestone, but not sandstone. Most of the 

ore was encountered between 375 feet and the bottom, but some was 

found all the way down. In the NE. \ sec. 3 recent drilling is reported 

to have developed a good body of lead ore at a depth of about 380 feet.

]£ast of Flat Eiver, on the Theodora tract, galena has been found in 

most of the holes put down. The ore is generally within 20 feet of the 

sandstone; but in one hole, situated in the midstof the others, some lead 

was struck at a depth of only 100 feet, and some more at about 200 feet.

North and east of the Leadington and Donnelly mines drill holes 

have been put down, between them and the corner of St. Geuevieve 

County, some 4 miles distant. Some little ore has been found, but not 

in many holes, and according to report it disappears eastward as the 

sandstone outcrop is approached. About a mile southeast of these 

mines some drilling done a year or so ago failed to discover any considerable amount of ore, but recently a quite rich find was reported from 

the same tract of land.

North of Simms Mountain and north of Flat Eiver, in sections 21 and 

22, several holes have been put down. One of these went to a depth of 

558 feet, and neither encountered any lead nor reached sandstone. In 

another a little ore was struck at 470 feet, and in still another galena 

was scattered between the depths of 460 and 554 feet. '

On the Derby Lead Company's land, in the S. £ of the SE. ^ sec. 13, 

in the NW. 4 of the NW. J sec. 19, and in the NE. J of the NE. I sec. 24, 

numerous deep drill holes have been put down. Ore was found in all 

below the depth of 450 feet. A workable body from 20 to 40 feet in 

thickness is reported, and galena is scattered through the rock for a 

depth of 80 feet or more. In the NE. corner of the NW. ^ sec. 24 a moderate quantity of ore is reported between the depths of 461 and 537 feet. 

In the SE. corner of the SW. ^ of the same section galena was found
U.S.GEOLOGICAL SURVEY. BULLETIN NO. 132. PL.VI.

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^JBRflNiTE. | "[SANDSTONE. |jg^v*?JoLDSURFACE DIGGINGS, p JUNDERGROUND MINES. | ]UIMESTONE 

A. ALTITUDE OF SURFACE. S,S. ALTITUDE CF SANDSTONE. D.DEPTH. i SHAFT. oDRiLLHoLE.

THE MINE LA MOTTE MINES.

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Ilth.A.Hoen &Co.Baltimore.

SCALE.
WJNSLOW.] GENERAL DISTRIBUTION OF THE ORE. 27

scattered through the rock between the depths of 445 and 490 feet. 

Nearly a mile east of the last, on the creek in the SW. corner of section 

19, a good showing of ore is reported between the depths of 539 and 548 

feet, and the loss of the bit prevented further drilling, though the hole 

was still in ore.

North of the railway junction west of Delassus a hole was put down 

in section 29, near the middle of the south line. No ore was found down 

to the depth of 472 feet, where the hole was abandone'd, but Mr. George 

Cole, who sunk the hole, believes that lead would have been found at 

625 feet. In the NE. £ sec. 32, just south, ore was passed through 

between depths of 480 and 615 feet, and in the NW. corner of section 4 

and the NE. corner of section 5, a mile south of the last, similar results 

were obtained.

About Farmington, and in the holes immediately northeast and northwest of that place, no lead ore has been found.

About Delassus a number of drill holes were put down five or more 

years ago a dozen or more within a mile or so south of the town; they 

were quite shallow, however, none being over 200 feet deep, and thus 

stopped well above the sandstone. A little galena was found between 

the depths of 75 and 100 feet, but nothing amounting to an ore body.

East of Doe Run between 4 and 5 miles several holes have been sunk, 

as indicated on the map. Of these, one sunk in the SE. corner of section 24 showed lead ore between depths of 460 and 472 feet, where drilling was stopped because of the breaking of the rod.

North of Knob Lick about 4 miles a drill hole in the NE. £ sec. 21 

revealed no ore.

North of Mine La Motte, in the northern part of the estate, drill holes 

have, so far, not encountered any ore, at least not in paying quantities.

About Fredericktown a good deal of drilling has been done within the 

past four or five years, and ore has been found at several places, though 

none has so far been developed. In a hole about 3 miles southeast of 

the town a few specks of lead were encountered at a depth of 115 feet. 

On the eastern edge of the town lead was found in a number of holes, 

in the lower 30 feet above the sandstone. North of the town about 

twelve holes were put down, close to the county road, between Village 

Creek and Mine La Motte; they varied in depth from 35 to 71 feet to 

the sandstone; no lead was found in any. About a mile southeast of 

these, on the south side of Village Creek, more holes were sunk, reaching a deptfi of 180 feet; some little galena was found in these. About 

4 miles northwest of the town, near the southwest corner of the Mine 

La Motte estate, is a bunch of drill holes of which the reports are quite 

promising; they range in depth up to 120 feet. The records of these 

holes show that the ore occurs in the lower part, perhaps 10 feet from 

the sandstone, and consists of a bed of limestone 10 to 15 feet thick, 

with the galena disseminated in it in coarse grains; some cores are 

quite rich.
28 LEAD ORES OF SOUTHEASTERN MISSOURI. [BULL. 132.

About 5 miles southeast of Fredericktown, on the St. Francois River, 

in section 15, west of Slater Creek and about a fourth of a mile east of 

the river, drill holes reached depths of 180 feet; no lead ore was found 

in any; the deeper holes reached sandstone, while those farther north 

went through limestone to granite without encountering any sandstone.

THE ORE BODIES.

The typical ore is the disseminated, consisting of grains of galena 

intimately mixed with grains of dolomite or calcite, the galena having 

been introduced by the process of metasomatic interchange. Sheet 

galena is sometimes found in vertical crevices at higher levels, associated with disseminated ore, but it disappears or is rare at depths. The 

galena of the disseminated ores is sometimes distributed uniformly 

throughout the face of rock exposed; elsewhere the mineral is concentrated about certain centers; and, again, the grains of galena are frequently strung out along the stratification planes, sometimes so close 

together as to form sheets, which vary in thickness from one-tenth of 

an inch to several inches.

The associated minerals are few and not conspicuous. Calcite is 

probably the most abundant; it is found in large crystals embedded in 

clay, in small crystals lining cavities, and in masses embedded in the 

limestone. Other minerals are iron pyrite, marcasite, chalcopyrite, 

pyrrtiotite, and the rare nickel-cobalt sulphide linnaeite. These generally occur in small quantities, but occasional bunches are found, as the 

experience at Mine La Motte, Bonne Terre, and the Donnelly mine 

shows. Chlorite, an abundant mineral in the limestone, is also often 

mixed with the galena.

The shapes of the ore bodies are very irregular and variable; at one 

point the galena may occupy a bed of limestone only a foot or two in 

thickness, while within a short distance the impregnation may expand 

to 10 or 20 feet, and faces of magnificent ore nearly 100 feet thick have 

been opened. As a rule, no well-defined planes limit these ore bodies 

in any direction, but the galena contents usually fade or "lean out" 

into the surrounding barren rock. In some instances, however, stratification planes or crevices mark the limits of the ore.

The horizon of the ore deposits is quite variable, but on the whole 

they are perhaps more prevalent in the lower part of the St. Joseph 

limestone, just above or a short distance away from the La Motte sandstone. The ore bodies at Bonne Terre are a notable exception to this, 

the lowest being 200 feet above the sandstone, and they extend thence 

to the surface. The nearness of the ore bodies to the sandstone is more 

pronounced in the Flat Eiver mines; but upper runs of ore are found 

also, as is illustrated in nearly all of the mines there. At Doe Run the 

deposit is near the bottom, and at Mine La Motte it also clings to the 

sandstone, but the basins are shallow in both places. About Fredericktown the ore is also found near the sandstone.
WINSLOW.] THE ORE BODIES. 29

The presence of crevices, commonly called " channels," traversing all 

of these mines, is a significant fact. In the deep workings they are not; 

as a rule, open fissures, but are quite tight, and are often traceable only 

by the drip of the water, with sometimes lenticular expansions. They 

often connect with the surface, where they are generally open, filled 

with clay, and contain galena in sheets. Such crevices at Bonne Terre 

are described in great detail in the report of the Missouri Survey. Many 

are encountered in the main workings there. The prevailing courses 

are between east-west and northeast-southwest. Many are nonpersistent, while some are continuous so far as the workings extend. No 

master crevice or series of crevices is definable: no faulting or displacement was observed. At the Desloge mine joint crevices were seen 

running from east to west, and the Bogy shaft followed a crevice from 

top to bottom. In all of the mines of the Flat Eiver camp such crevices 

traverse or are contiguous to the ore bodies, as already referred to, and 

all have courses nearly east and west. They are abundant at Doe Kun 

and at Mine La Motte. They undoubtedly favor the accumulation of 

ore in furnishing passages for the flow of the solutions, but they can 

not be regarded as of the nature of profound fissures through which 

solutions have risen from depths. For the same reasons faults are conducive to the formation of ore, but there is only one instance of close 

association, i. e., at Mine La Motte.

The texture and composition of the rock has doubtless some bearing 

upon the ore contents. Thus, the deposits are most prevalent in the 

coarse, open-textured rock, and they also characterize the darker-colored 

varieties, which doubtless contain some organic matter. Shaly, dense 

beds have their influence in directing the flow of the waters which 

traverse them, and hence they indirectly affect the distribution of ore 

bodies.

The fact that the deposits of Mine La Motte.and on Flat Eiver are 

along or near the axes of basins suggests that there may be something 

in this structure favoring the accumulation of ore, and the results of 

drilling south of Flat Eiver also indicate that ore occupies the center of 

the trough. It seems natural that this should be the case, as the waters 

or solutions which traverse the rocks from the surface would gravitate 

toward the center of a basin, and, other conditions being favorable, 

it would thus be also a center of accumulation. The force of this suggestion is weakened, however, by the location of the Bonne Terre, Donnelly and Leadington, and Doe Eun deposits, which are well up on the 

sides. The absence of ore over the margin of the formation, in the 

lower beds which crop out just west of the St. Genevieve County sandstone area, is worthy of note.

A glance at the map shows that all of the deposits so far developed 

are beyond the areas of the Potosi limestone, and drill men are of the 

opinion that the ore does not occur in disseminated form beneath that 

cherty rock. This may be the case, but the fact is hardly demonstrated
30 LEAD ORES OP SOUTHEASTERN MISSOURI. [BULL. 132.

yet, as inherent difficulties in drilling have prevented holes from being 

sunk through these rocks. If, however, it prove true that these great 

ore bodies as a whole are restricted to the country whence these upper 

rocks have been removed, or, in other words, where denudation and 

subaerial decay have been greatest, then this is a significant fact. It 

is in entire harmony with the writer's hypothesis of the origin of the 

ores. This hypothesis has been so fully presented in the Missouri Survey report that it will be only very briefly outlined here. It derives the 

deposits from the metals diffused through the country rocks, by means 

of the surface decomposition of the latter. Minute quantities of the 

metals being present in not only the limestones but the Archeau rocks 

also, as has been demonstrated by analysis^, the metals would naturally 

pass into solution on the decay of these rocks and be transferred in percolating waters through crevices and other openings to the underlying 

strata, where they would gather by segregation into deposits of various 

forms and kinds. In the case of the disseminated ores, the waters 

flowing from the underlying sandstone doubtless carry metals in solution in minute quantities, largely derived directly from the remains of 

decaying Archean rocks. These, on entering the limestones, find conditions (which were not afforded in the sandstone) suitable for the 

replacement of the country rock by galena and for the formation of ore 

bodies. The metal-containing waters can have found access in other 

ways also.

In conclusion, the maps and sections accompanying this report show 

very clearly the limits of the different formations, including the orebearing St. Joseph limestone, beyond which it is not advisable to search 

for disseminated ores. They also define the basins or troughs; and, 

though it can not be maintained that the ore^ deposits are confined to 

these, the writer recommends that these basins be given special attention in the search for ore. Moreover, it is a fact that the developed ore 

bodies are generally, though not invariably, under areas over which 

shallow surface deposits have been worked in the past; therefore, other 

things being equal, such localities should be given the preference. 

Ground which is known to be traversed by crevices or faults is also to 

be regarded favorably. It is of great importance to the future of this 

district that some systematic effort be made to collect and preserve 

more carefully the results of the drilling which has been done and is 

being constantly extended by individuals and companies. Only the 

most general results have been introduced here; could they be more 

thoroughly studied and compared, mapped and leveled, much of value 

could be determined which is here only suggested.
INDEX.

Archean rocks, character and distribution

of.................................. 11-12

Austin, early discovery of galena mentioned by....................... 10

Avon, mines and mining at.............. 9,10,25

Bauman, D., acknowledgments to .......... 7

Bilharz, O. M., acknowledgments to........ 7

Bonne Terre, record of boring at........ 13-14,16

mines and mining at........... 9,10, 20-21,26

Brockmeyer, H. C., acknowledgments to ... 7

Central Lead Company, record of boring of. 16

mining Avorks of ....................... 23

Cole, George J., acknowledgments to....... 7

Crawley shaft of St. Joseph Lead Company's mine, description of......... 24,

Crevices or channels in mines, significance

of.................................. 28-29

Delassus, mining near...................... 27

Derby Lead Company, record of boring on

land of............................. 17

mining works of....................... 23,26

Deslogo Consolidated Lead Company, mining works of....................... 10,21

Doe Kun, mines and mining at........... 9,10,24

record of boring at...................... 14

mining near ........................... 27

Doe Kun Lead Company, mining works of 22-23, 24 

Donnelly Lead Company's shaft, description of.............................. 24

Faults of the region ....................... 19-20

Featherstonhaugh, cited on early lead-ore

digging at Mine La Motte .......... 9

Plat River, mines near ..................... 26

Plat Eiver Camp, mines and mining at.... 9,10,

21-24, 26

Plat Eiver Lead Company, mining works of 21-22 

Fredericktown, mining near ............... 26

French Village, mining near............... 26

Haworth, cited on relations of granites and

porphyries......................... 12

Iron Mountain conglomerate, character and

distribution of..................... 12

PageKnob Lick, mines near..................... 27

La Grave, Francis, lead ore at Bonne Terre

found by ........................... 10

La Motte sandstone, character and distribution of........................... 12-14

Leadingtou Lead Company's shaft, description of ............................. 24

Mills, James E., cited on thickness of limestone at Mine La Motte............ 17

Mine La Motte, mines and mining at.. 9,10, 24-25 

early lead-Ore digging at............... 9-10

record of borings at.................... 13,15

thickness of cherty limestone at....... 17

faults at................................ 19-20

Mines of the region enumerated and described ........................... 9,20-25

Ore bodies, of the district, locations and

character of........................ 28-30

shape of................................ 28

horizon of.............................. 28

Ore of the district, character of.1.......... 28

associated minerals of.................. 28

origin of................................ 30

Potosi limestone, distribution and character of..................... .......... 17-18

St. Francois Eiver, mining on............. 27

St. Joseph Lead Company, short history of

operations of....................... 10

mines of....................... 20-21,24,25,26

St. Joseph limestone, character and distribution of........................... 14-15

Schulte, Frank, acknowledgments to...... 7

Shumard, B. P., cited on geologic place of

La Motte sandstone.............!.. 12

'Simms Mountain, record of shaft at....... 14

mines near............................. 26

Stratigraphy and lithology of the rocks of

the region.......................... 11-18

Structure of the rocks of the region....... 18-20

Thacher, Arthur, acknowledgments to..... 7

Topography of the region.................. 10-11