98 ALASKA GLACIERS 



distance the plain is bounded at the sides by rock walls, 

 continuous with those containing the glacier, but these 

 end at the general line of coast, and the plain flares beyond 

 them as a low, broad cape. It is in fact a delta of glacial 

 detritus, filling the lower part of the glacier trough and 

 encroaching on the bay. The building of the plain is 

 rapid. Its upper part was almost barren, as we saw it, 

 only supporting enough scattered young spruces to show 

 that their spread was not absolutely prohibited by soil or 

 climate. Lower down were plantations of vigorous young 

 cottonwoods, but no mature groves were seen. Border- 

 ing lands of earlier origin are covered by spruce forest, 

 and in places the growing gravel deposit was evidently 

 invading the forest, overwhelming the undergrowth and 

 burying the roots of large trees so that they languished 

 and died. I was impressed with the fact that the quantity 

 of rock waste discharged by the glacier was much greater 

 than would normally be discharged by a stream of water 

 draining a similar area. 



The glacier bore no large moraines, and its generous 

 output of rock waste must have been supplied chiefly by 

 the englacial drift. The visible belt of this drift was 

 broad at one or two points, but in general so narrow as to 

 give the impression that the base of the ice lay consider- 

 ably below the level of the gravel plain. The ice front 

 was steep, probably ranging from 20 to 30, and im- 

 pressed Dall as much steeper than in 1895. It was de- 

 cidedly steeper than the front of Hidden Glacier and the 

 north front of the Hugh Miller, observed a month earlier, 

 but less steep than non-tidal portions of the Columbia. 

 If the correlation of high and low frontal slopes with ad- 

 vance and retreat is well founded, the Columbia and 

 Grewingk glaciers were advancing in 1899 and the Hid- 

 den and Hugh Miller were retreating. If the slopes are 

 related to the direction of the sun, those toward the south 



