E.' L. Berthoud—McCMlaii Mountain, Colorado. 109 



are workinginto the vein horizontally by excavating a drift. The 

 ores found in these mines are galena rich in silver, decomposed 

 quartz and honey-combed quartz, with sulphurets of silver, and 

 some decomposed iron pyrites and a little carbonate of lead, with 

 occasional small patches of sphalenite. 



I have been thus particidar in the description of these mines, 

 merely to give a good general idea of their value and location. 

 In a personal and critical examination of them, during a recent 

 visit to the region, a peculiar feature was observed which excited 

 much surprise. 



The discovery-drift of the Centennial Lode runs into Mc- 

 Clellan Mountain at an altitude above 18,100 feet, on a course 

 southwest, at about 80 feet from the entrance of the tunnel. 

 Intercalated in the vein, I found three or four well defined 

 veins of solid ice, parallel with thebeddingof the rock, and filling 

 all its thinner side cracks and fissures ; in fact, after further exam- 

 ination I found that the frozen stratum, and the congealed, hard 

 earth, rock and gravel, began only a few feet below the accumu- 

 lated rock and debris of the mountain slope, and continued as 

 far as the excavation reached, some forty feet in depth. 



From the Centennial Lode I went westward about 300 feet, 

 and examined the drift that has been excavated into the moun- 

 tain some 500 feet, upon the vein of the International Lode. 

 Here there is repeated the same frozen substratum and the same 

 rift or veins of ice in the country rock and in the vein. I 

 went into the tunnel about 100 feet and found this glacial con- 

 dition still existed ; and the owner of the mine assured me that 

 the ice and frozen rock continued all the way to the end of 

 the tunnel and caused a i:ood deal of extra expense in mining 



The course of the " International Lode" is southwest, and its 

 drift is about 50 feet in vertical elevation above the drift of the 

 Centennial Lode. 



The next '' Lode" examined was the Belmont Lode, west and 

 nearly parallel to the International. This mine is exploited by 

 a system of horizontal galleries one above the other to the sum- 

 mit of the mountain, at 13,400 feet elevation. In the lower gal- 

 leries the same frozen icy condition prevails as at the first two 

 veins. But the summit drift, which was at the date of ray visit 

 about 60 feet long, does not show veins of ice in the wall-rock 

 of the veins ; this is probably due not only to the greater narrow- 

 ness of the summit, here scarcely 200 feet where pierced by the 

 tunnel, but also to the influence of wind and sun upon its 

 western seamed and riven surface, and to its more perfect 

 drainage and exposure. 



This is certainly a singular phenomenon, when we consider 

 that across the narrow valley north of McClellan Mt, not over 



