Studies in the Sierra 



199 



resented by the large arrows, which descended from the flanks 

 of Mounts Dana, Gibbs, Ord, and others to the south. For thirty 

 miles farther, we find everywhere displayed the same delicate 

 yielding to glacial law, showing that, throughout the whole pe- 

 riod of its formation, the huge granite valley was lithe as a ser- 

 pent, and winced tenderly to the touch of every tributary. So 

 simple and sublime is the dynamics of the ancient glaciers. 



Every valley in the region gives understandable evidence of 

 having been equally obedient and sensitive to glacial force, and 

 to no other. The erosive energy of ice is almost universally 

 underrated, because we know so little about it. Water is our 

 constant companion, but we cannot dwell with ice. Water is 

 far more human than ice, and also far more outspoken. If gla- 

 ciers, like roaring torrents, were endowed with voices commen- 

 surate with their strength, we would be slow to question any 

 ascription of power that has yet been bestowed upon them. 

 With reference to size, we have seen that the greater the ice- 

 fountains the greater the resulting valleys ; but no such direct 

 and simple proportion exists between areas drained by water 

 streams and the valleys in which they flow. Thus, the basin of 

 Tenaya is not one-fourth the size of the South Lyell, although 

 its canon is much larger. Indeed, many canons have no streams 

 at all, whose topographical circumstances are also such as dem- 

 onstrate the impossibility of their ever having had any. This 

 state of things could not exist if the water streams which suc- 

 ceeded the glaciers could follow in their tracks, but the mode 

 and extent of the compliance which glaciers yield to the topog- 

 raphy of a mountainside, is very diiferent from that yielded by 

 water streams; both follow the lines of greatest declivity, but 

 the former in a far more general way. Thus, the greater por- 

 tion of the ice-current which eroded Tenaya Canon flowed over 

 the divide from the Tuolumne region, making an ascent of over 

 500 feet. Water streams, of course, could not follow; hence 

 the dry channels, and the disparity, to which we have called at- 

 tention, between Tenaya Canon and its basin. 



Anyone who has attentively observed the habits and gestures 

 of the upper Sierra streams, could not fail to perceive that they 

 are young, and but little acquainted with the mountains ; rush- 

 ing wildly down steep inclines, whirling in pools, sleeping in 



