Studies in the Sierra 



183 



separate pinnacles about 700 feet in height, set upon the main axis 

 of the range. Glaciers are still grinding their eastern bases, illus- 

 trating in the plainest manner the blocking out of these imposing 

 features from the solid. The formation of small peaklets that 

 roughen the flanks of large peaks may in like manner be shown to 

 depend, not upon any up-thrusting or down-thrusting forces, but 

 upon the orderly erosion and transportation of the material that 

 occupied the intervening notches and gorges. 



The same arguments we have been applying to peaklets and pin- 

 nacles are found to be entirely applicable to the main mountain 

 peaks ; for careful detailed studies demonstrate that as pinnacles are 

 separated by eroded chasms, and peaklets by notches and gorges, so 

 the main peaks are separated by larger chasms, notches, gorges, val- 

 leys, and wide ice-womb amphitheaters. When across hollows we 

 examine contiguous sides of mountains, we perceive that the same 

 mechanical structure is continued across intervening spaces of every 

 kind, showing that there has been a removal of the material that 



once filled them — the occur- 



rence of large veins oftentimes 

 rendering this portion of the ar- 



gument exceedingly conclusive, 

 as in two peaks of the Lyell 

 group (Fig. 3), where the wide 

 veins, N N, are continued 

 across the valley from peak to 

 peak. We frequently find rows 



of pinnacles set upon a base, 



the cleavage of which does not admit of pinnacle formation, and in 

 an analogous way we find immense slate mountains, like Dana and 

 Gibbs, resting upon a plain granite pavement, as if they had been 

 formed elsewhere, transported and set down in their present posi- 

 tions, like huge erratic boulders. It appears, therefore, that the lof- 

 tiest mountains as well as peaklets and pinnacles of the summit re- 

 gion are residual masses of the once solid wave of the whole range, 

 and that all that would be required to unbuild and obliterate these 

 imposing structures would simply be the filling up of the labyrinth 

 of intervening chasms, gorges, canons, etc., which divide them, by 

 the restoration of rocks that have disappeared. Here the important 

 question comes up. What has become of the missing material, not the 



