U. R. GEOLOGICAL SURVEY 



BULLETIN' 707 PLATE LXX 



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SPIRES OF VOLCANIC ROCK NEAR SAPINERO. 



Much of this country was once covered with volcanic tuff consisting of frajrmenls of 

 lava of all sizes, which is bedded like shale or clay. It is soft and is readily cut by 

 rain and streams into beautiful and fantastic forms. Photograph by Willis T. Lee. 



B. INTRICATE EROSION OF VOLCANIC ROCK. 



This mass of volcanic tuff is so dissected by rain erosion that it consists only of numberless 

 spires and pinnacles. It makes picturesque cliffs that are hard to climb. Similar sheets 

 of tuff cover the hills on both sides of Gunnison Valley. Photograpli by Willis T. Lee. 



C. SHKKP I^ THE GU.NMSO_\ COLNTRY. 



Many sheep are pastured in the Gunnison country. In midsummer they reach the 

 higher slopes of the mountains, as shown in this view. Photograph by J. F. Hunter. 



