604 THE STE. GENEVIEVE COUNTY COPPER MINES. 



The property is situated io the county of Ste. Genevieve, State of Mis- 

 souri, in and about ten miles west of the town of Ste. Genevieve, which is 

 on the Mississippi river, sixty miles below St. Louis. 



Topography. — The county is undulating, with hills from 150 to 200 feet 

 in height, with here and there valleys sufficiently wide for agricultural 

 purposes. The limestone constituting the substructure of the hills is cov- 

 ered with a deep soil ; but here and there the soil has been carried away by 

 erosion, laying bare the rock, and in many places leaving a seam of copper 

 ore exposed. 



Geology — The geology of the copper ore district belongs to the Upper 

 Silurian formation which extends far to the West and reaches within a few 

 miles of the river on the Bast, at which point the "Carboniferous system" 

 occupies the intervening district to the river. The copper ore occurs in 

 three, possibly four, distinct beds. 



The Harris Mine. — The copper ore at this point occurs in three beds ; 

 the lower bed is situated far down the hillside, and as yet is not developed ; 

 the middle bed which is by far the most important, occurs on or about the 

 75 feet contour line of the hill ; this belt lies horizontal, and between the 

 layers of limestone. Immediately below the ore bed is a stratum of quartz or 

 iiint of several inches in thickness ; then the hard, dense limestone. Imme- 

 diately overlying the ore bed is another thin stratum of flint, and then the 

 Silurian limestone, which extends to the top of the hill. Near the summit 

 of the hill the third ore bed occurs, which, like the first, is undeveloped ; 

 but both the first and third promise upon further development to equal in 

 quantity and quality the middle deposit of ore. 



As the three deposits are so similar in their character, both mineralog- 

 ically and geographically, a description of one will answer for the others: 

 The ore bed proper is a horizontal stratum between the limestone beds, un- 

 dulating with them and partaking of their folds, and though the folds are 

 continually changing, they remain almost at a uniform level. The ore bed 

 changes in thickness from six or eight inches to several feet; and on meas- 

 uring the beds at a number of points, I consider a foot in thickness a low 

 average. Near the surface in the clay and on the exposed rocks the ore has 

 to a great extent been transformed into green and blue carbonates ; but as 

 the hill is penetrated the sulphuret occurs, mixed with carbonates and red 

 oxides; and at a distance ot 100 feet the carbonate gradually diminished 

 being replaced by red oxide with considerable sulphuret. The exj)erience at 

 every point has been that the ore increases in richness and quantity as the 

 hill is penetrated, not unfrequently being several feet in thickness of almost 

 pure red oxide and sulphuret. 



The mines are invariably free of water, no trouble being experienced 

 except immediately after heav}^ rains ; and this trouble can soon be obvi- 

 ated as the mines admit of a fine system of drainage, as tunnels can be run 

 into the hillsides, draining off the waters into the valleys below. 



The percentage of the ore varies ver}^ widely, according to the character 



