354 DESCEIPTIVE GEOLOGY. 



for its singular beauty, and will be found well represented in Volume I. 

 The scenery of the interior of the mass is of a truly alpine character, espe- 

 cially in the spring and early summer, when the upper portions of the 

 canons are still deeply buried beneath the winter's accumulation of snow. 



While glacier-action has doubtless played an important part in the 

 formation of most of tlie canons and gorges, the traces of this action now 

 remaining vary with the character of the enclosing rock, and the relations 

 of their direction to the structure-lines. Where the rock is hard and homo- 

 geneous, as in Little Cottonwood Canon, the evidences of glacier-action are 

 apparent even to the uneducated eye. This cailon is a long, almost straight 

 gorge, Avhose cross-section would represent a U-shaped depression, its bot- 

 tom, especially toward the mouth, filled with huge rounded boulders of the 

 granite out of which it has been carved, while its walls present smoothed 

 and rounded surfaces. Big Cottonwood Canon, on the other hand, while 

 still showing some traces of glacier-action, and even large moraines, in its 

 upper portion, is toward the mouth a narrow V-shaped ravine, whose course 

 forms a zigzag line, running to and fro between the strata of quartzite, to 

 find a more yielding point at which to break tlu'ough them. The little trib- 

 utary ravines on the south side of either of these canons, which occupy a 

 much higher level, show traces of wearing by ice at a very rec^t period, 

 having rounded amphitheatre-like heads, and frequently little shallow glacier- 

 lakes. The most remarkable of these is the Three-Lake fork of Big Cotton- 

 wood, just east of Twin Peaks, where, over an extent of many acres, glaciers 

 have grooved and polished the hard surface of a bed of dark argillaceous 

 quartzite, and covered it with a thin weathered coating of a "brick-red color. 

 The three little lakes occupy three different levels in this glacier-basin, and 

 are connected by pretty cascades, of which the lower, being triple, is exceed- 

 ingly picturesque. 



The main system of glaciers, as is shown by the topography as well 

 as by moraines and the shapes of the canons, radiated out from the high 

 mass around Clayton's Peak. Most of these glaciers did not extend to a 

 very low level. That of Little Cottonwood, however, as shown by the reg- 

 ular shape of the canon and the rounded boulders at the mouth, must have 

 extended at least as low as the shore of the ancient lake which once filled 

 the Utah Basin ; that it actually protruded into the Jordan Valley is ren- 



