480 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



also found. We have the famous "Washoe silver mines in Utah. 

 In Illinois and Kentucky is the subcarboniferous limestone, pro- 

 ducing some silver and lead ; and it makes its appearance again 

 in the Organ mountains of New Mexico, where Ave come imme- 

 diately into silver and lead bearing ores again, the silver having 

 become richer as we go westward. Probably this is the same 

 with the great silver formation of Chihuahua in Mexico, extend- 

 ing into Central America and into South America. By the 

 upheaval of the Rocky mountains, both the Carboniferous lime- 

 stone and the Cretaceous series were broken in two, and they 

 appear again upon the eastern slope of the Sierra Nevada. But 

 the rocks of California belong to an entirely different age, so 

 that geologically it is in vain to look for silver, west of the 

 Sierra Nevada, in the same richness and profusion which it dis- 

 plays in the Washoe mines. Now, to come to the Pike's Peak 

 region ; Avherever the primitive formation have been upheaved 

 and brought to the surface, they have brought gold with them ; 

 and I have no doubt that, gold will be found along this entire 

 range of mountains. But it is not found in placer deposits, as 

 in California, and consequently it will not pay the miner as well. 

 It is usually found in this region in the primitive quartz. The 

 gold of North Carolina, extending from Virginia into Georgia, 

 that in Vermont, that upon the Chaudiere river in Canada, and 

 that in Nova Scotia, are all of the same formation. 



At Lake Superior we begin with the copper, which is found in 

 connection with calcareous spar, and is sometimes found in 

 immense masses. A new theory has arisen within a few years, 

 viz.: That all minerals were at one time pretty uniformly distri- 

 buted through the mass of the rock, while it was in a soft pulpy 

 condition; and that the metal was gathered from the entire mass, 

 probably by electrogalvanic action, and brought into a vien. 

 Lime was also in solution in the same mass, and by the same 

 agencies was brought into the same vein. This would explain, 

 why we find the copper distributed as it is between these crystals 

 of calcareous spar which show no efiect of heat upon them. The 

 celebrated Mr. Crosse filled a box with clay, silex, and lime, uni- 

 formly mixed. He then formed an artificial vein, and subjected 

 the whole to the action of electricity. After some months the 

 silex had collected in this artificial vein, forming a true quartz 

 vein. I have explained, on a former evening, that upon the 

 Welsh coast copper is even now in the process of formation. In 



