Geol.— Vol. I.] TURNER— ORIGIN OF YOSEMITE VALLEY. 273 



moraines carried out by the ice have been completely 

 worked over into other physiographic forms, so as to be no 

 longer recognizable as moraines. 



We have here, however, enormous alluvial fans clearly 

 the result of water action ; and these fans contain approxi- 

 mately sufficient material to fill up the canyons from the 

 degredation of which they were formed, and are in them- 

 selves sufficient proof, as it seems to me, that the canyons 

 of the east slope of the Sierra were cut out by water action. 



The amount of morainal material in these canyons is insig- 

 nificant as compared with the amount of material in the allu- 

 vial fans which proceed from them. The same may be said 

 of the much larger canyons of the western slope, the detrital 

 materials of which are plainly spread by water action in the 

 Great Valley. 



GlaciaLion of the Inyo Mountains and of the Sotithern 

 Sierra Nevada. — The precipitation at the present time in 

 the Inyo Mountains is extremely low, probably not over 

 five inches in the southern part of the range and not exceed- 

 ing fifteen inches on White Mountain, near the northern 

 end. These extremes are merely estimated, no exact rec- 

 ords having been kept in the range itself. However, at 

 Independence, in Owen's Valley, a record has been kept, 

 partly by the surgeons of the U. S. Army and partly by the 

 Weather Bureau.^ The extremes of the rainfall from 1865 

 to the present time, so far as the records indicate, are 21.63 

 inches for 1867 and 1.12 inches for 1869, the average for 

 twelve years being 6.1 inches. The estimated small precip- 

 itation in the Inyo Mountains, when taken in connection 

 with the great elevation of the range, White Mountain being 

 about 14,200 feet high, is remarkable. The adjacent por- 

 tions of the Sierra which reach this altitude have a precipi- 

 tation several times as great. So far as known there has 

 not been observed up to the present time any evidence of 

 the former existence of glaciers in the Inyo Mountains. 



1 I am indebted to Prof Willis L. Moore, Chief of the Weather Bureau, for a table of 

 the precipitation at Independence. 



