GLACIAL WORK IN WESTERN MOUNTAINS 73 I 



gathered for a number of localities where detailed work in the 

 near future seems desirable. In addition to preliminary studies 

 of this sort, glaciation was found to have occurred in some 

 localities from which it has not heretofore been reported. For 

 example, it was found that glaciers affected the north slope of 

 both the Spanish Peaks of Colorado. These mountains, 12,708 

 and 13,623 feet high respectively, appear to have represented 

 about the limiting conditions for glaciation, for the glaciers of 

 both mountains were small, and confined to their northern 

 slopes. One of the limiting conditions here was doubtless the 

 small area which could serve as a catchment basin on either 

 peak. Had the areas of these mountains been larger, more 

 considerable glaciation would doubtless have been developed at 

 this altitude. 



It was found, among other things, that the detailed study of 

 glacial problems will locally have an important economic bear- 

 ing. An extensive placer mining plant is being established at 

 Breckenridge, Col., to wash the glacial moraine matter of the 

 Blue River valley, and the gravels of the valley train below. 



RoLLiN D. Salisbury. 



