9 8 
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 Dali 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 
