U. S. GEOLOGICAL SURVEY 



BULLETIN 612 PLATE XLVII 



A. DONNER LAKE. 



Glaciated ledge of granite in the foreground. Photograph furnished by Southern Pacific Co 



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B, DESOLATION VALLEY, NEAR LAKE TAHOE. 



Characteristic view of the higher Sierra even in midsurr^mer. 

 rock ledges testify to the scouring action of the ice that 

 Southern Pacific Co. 



The bare and more or less rounded surfaces of the 

 has moved over them. Photograph furnished by 



