9 6 
ALASKA GLACIERS 
part of the Harriman from the northwest (pi. xv). No 
measurements were made, but it is evident from an inspec¬ 
tion of photographs that the heights of such features in 
this neighborhood are approximately the same as in the 
vicinity of Serpentine and Surprise glaciers, and it is 
possible that a number of minor glaciers observed on both 
sides of the fiord constitute with these a general system. 
Roaring Glacier, between the Cataract and the Harriman, 
owes the peculiarity suggesting its name to an abrupt 
change of grade. From a comparatively gentle slope it 
passes to one so steep that loose masses find no lodgment, 
and as its movement steadily projects its end beyond the 
point of inflection, fragments of ice break away and tumble 
down the steep incline, to gather in a heap far below, where 
they lie until melted. 
The condition of extreme glaciation to which these phe¬ 
nomena point does not belong to the series of modern 
changes, and will be referred to again in the chapter on 
the Pleistocene history. Were it of comparatively recent 
date the fiord would now be destitute of trees, but such is 
not the fact. It is true that the slopes are bare in the 
immediate vicinity of the glaciers, and that the valley 
walls enclosing the greater glaciers — the Barry, Serpen¬ 
tine, Surprise and Harriman—support no trees, but the 
lower parts of the fiord walls are elsewhere covered by a 
hemlock forest. 
As to the proper interpretation of the peculiarities of 
forest distribution the case is not altogether clear. In 
other localities there has seemed good reason to ascribe 
absence of forest to recent occupation by ice, but here 
there is a sort of transition from forest to barren which 
suggests climatic limitation. In the zone of transition the 
trees are not young and vigorous, as when invading newly- 
acquired territory, but scrawny and ill-favored, as though 
struggling desperately against the attack of hostile condi- 
