Studies in the Sierra 



191 



the features, and, indeed, the very existence, of overflowed moun- 

 tains are in great part due neither to ice, water, nor any eroding 

 agent whatsoever, but to building forces — crystalline, perhaps — 

 which put them together and bestowed all that is more special in 

 their architectural physiognomy, while they yet lay buried in the 

 common fountain mass of the range. 



The same silent and invisible mountain-builders performed a 

 considerable amount of work upon the down-flowed mountains of 

 the summit, but these were so weakly put together that the heavy 

 hand of the glacier shaped and molded, without yielding much com- 

 pliance to their undeveloped forms. Had the unsculptured mass of 

 the range been everyway homogeneous, glacial denudation would 

 still have produced summit mountains, differing not essentially from 

 those we now find, but the rich profusion of flank mountains and 

 mountainets, so marvelously individualized, would have had no ex- 

 istence, as the whole surface would evidently have been planed down 

 into barren uniformity. 



Thus the want of individuality which we have been observing 

 among the summit mountains is obviously due to the comparatively 

 uniform structure and erodibility of the rocks out of which they have 

 been developed ; their forms in consequence being greatly dependent 

 upon the developing glaciers; whereas the strongly structured and 

 specialized flank mountains, while accepting the ice-currents as de- 

 velopers, still defended themselves from their destructive and form- 

 bestowing effects. 



The wonderful adaptability of ice to the development of buried 

 mountains, possessing so wide a range of form and magnitude, seems 

 as perfect as if the result of direct plan and forethought. Granite 

 crystallizes into landscapes; snow crystallizes above them to bring 

 their beauty to the light. The grain of no mountain oak is more 

 gnarled and interfolded than that of Sierra granite, and the ice-sheet 

 of the glacial period is the only universal mountain eroder that 

 works with reference to the grain. Here it smooths a pavement by 

 slipping flatly over it, removing inequalities like a carpenter's plane; 

 again it makes inequalities, gliding moldingly over and around 

 knotty dome-clusters, groping out every weak spot, sparing the 

 strong, crushing the feeble, and following lines of predestined beau- 

 ty obediently as the wind. 



Rocks are brought into horizontal relief on the sides of valleys 



