702 GEOLOGY AND TOPOGRAPHY OF THE LEAD REGION. 



continued to add pumps, engines, and pumping machinery at intervals. At the time 

 the mine was visited (June, 1874), there were in operation two steam pumps, and two 

 large lift, pumps, together with three boilers and two engines, one of them about thirty 

 horse power. The company then contemplated adding a larger engine and machinery. 

 It was estimated that about a thousand gallons of water per minute were being pumped 

 from the mme, and when the lower opening is reached, which is thought to be about 

 fifteen feet deeper, it will become necessary to pump about fifteen hundred gallons per 

 minute. 



The mine is in the upper beds of the Galena limestone, which is here present in its 

 full thickness, and indeed the first few feet of the shafts are sunk through the lowest bed of 

 the Cincinnati group, as may be seen from the yellow clay with the characteristic shells 

 in any of the shallow, prospecting holes in the vicinity. The following section of the 

 strata, penetrated in sinking the pump-shaft, will give a correct idea of the formations 

 here represented: 



Cincinnati Group. 



Ft. In,, 



Soil and clay bed 20 



Pipe clay 10 



Bed of black clay 4 



Shaly layers 10 



Galena Limestone. 



Galena limestone in thin layers 4 



Galena limestone cap in layers 4 feet thick, gradually increasing in 



thickness to the bottom 30 



Opening containing ore 30 



Total depth of shaft 86 00 



The course of the vein is nearly east and west, and five shafts have been sunk upon 

 it, the deepest of which has reached a point 105 feet below the surface. The opening 

 now presents the appearance of a series of large rooms or caves, from 15 to 20 feet wide 

 and about 15 feet high, for a distance of 600 feet. 



The vein was crossed in several places by bars of hard rock, one of which was sixty- 

 five feet in thickness. The bars always caused a decrease in the size of the opening, 

 and sometimes nearly cut off the vein. In other places the opening contracted in width, 

 in, wMch case the ore usually occurred in a solid sheet, sometimes as much as seven feet 

 tluck by seven and a half high. In the caves or larger parts of the opening the ore was 

 found in large masses, weighing sometimes several thousand pounds. Two large mas- 

 ses were found which weighed respectively fifty thousand and twenty-seven thousand 

 pounds. With the ore large masses of rock were found mixed with loose dirt and a fine 

 dark clay. The sides of the opening were much washed and worn by water, showing 

 a very regular stratification with no appearance whatever of faults or dislocations. Each 

 of the caves in the opening had a chimney going down, apparently to a second open- 

 ing, which has never yet been proved or worked. The upper part of the opening was 

 sometimes filled with a large key-rock, having a crevice on each side of it. Some- 

 times, however, the key-rock was replaced by a flat-cap-rock containing crevices. 



The appearance of these caverns as we passed through them was a sight not soon to 

 be forgotten. On the floor lay great masses of rock which had fallen from a bove, with 

 clay continually moistened from the dripping walls and arching roof, and here and there 

 the feeble light revealed rich masses of glittering ore. 



