IOWA ACADEMY OF SCIENCES. 
37 
The mine was discovered in January 1891, by Capt. Turner, 
who had reached the conclusion that lead was to be found in 
the Oneota, and had done considerable prospecting at various 
points along the Mississippi. This location is on a hillside 
that slopes to the north and east. While the general direc- 
tion of the crevices is nearly north and south (S. 10^ E. N. 10^ W.), 
its course is not straight, but zig-zags back and forth within 
certain limits, so that a shaft sunk on the general line of the 
fissure may be several feet out of the way. 
This sheet of mineral has been followed 1,000 feet, and its 
limits have not been reached, either to the north or south. At 
the north end of the present workings the fissure is interrupted 
by a ravine, and the sheet thus outcrops. There is good reason 
for supposing that this will be found again on the other side. 
The main body of the sheet has a vertical extent of from 25 to 
30 feet, and a width of from 3 to 4 inches. A shaft was sunk 
113 feet to the Saint Croix or Potsdam sandstone, and Galena 
was found in small quantities downward to within 4 or 5 feet of 
the latter. The bulk of the ore, however, is about 50 feet above 
the sandstone. 
The sheet of lead is either imbedded in the crevice clay, or 
fills the entire space between the rock walls. Where it extends 
into the hill to the south, and ’ has been little exposed to weath- 
ering agencies, the sides of the fissure have not undergone 
decomposition, and the sheet is in contact with the rock. In 
other places where examined an inch or two of clay was found 
between it and the limestone; the crevice in this case being 
from 6 to 8 inches wide. Again, the fissure may open out until 
it has a width of 3 or 4 feet, and is filled with clay and the 
sheet of ore. The latter lies up against the wall, and almost 
invariably against the east wall, or toward the lower side of the 
hill. The sheet does not extend vertically to the surface, but 
in the upper 8 or 10 feet, curves over toward the east, or down 
the slope. Evidently there has been a slipping of the hillside 
which has carried with it the top of the sheet, this bending 
being a result. 
The mine has been worked by means of three or four shafts, 
from 30 to 60 feet deep. From these, drifts are run in each 
direction at various levels, and thus the ore is removed. At 
the north end of the present workings a tunnel has also been 
cut alongside of the mineral. 
Most of the ore is taken out in pieces of considerable size. 
The Galena does not occur well crystalized, but in the form of 
