13 ° 
ALASKA GLACIERS 
water do not in general rise very nearly to the plateau 
plane, and we were frequently able to see that those 
farther back are higher. Even where the channels 
between islands are most sharply incised it is probable 
that they are excavated in the bottoms of broader hollows. 
My general conception of the configuration at the date 
of the lower peneplain — a conception necessarily vague, 
as well as provisional — is that it included all phases of 
the topographic cycle, being infantile to adolescent where 
the rocks are most resistant, adolescent to mature in the 
greater part of the Alexander Archipelago, and senile 
where the rocks are weakest. In the granites were nar¬ 
row gorges, set far apart, and reduced to low grade only 
where draining large tracts. Between them were tabular 
uplands with mild relief, except for occasional unreduced 
peaks, or monadnocks. In the stronger metamorphics a 
system of graded waterways divided the upland into 
mountain ridges, with scattered remnants of the summit 
plain. The master streams were largely consequent to 
the seaward slope of the old plain, but were in part 
diverted to lines of strike; and minor streams were ad¬ 
justed to rock structure. 
Low Peneplains .—Along the passages and channels 
we traversed, bold coasts are the rule and forelands of 
any character the rare exception, but at two localities we 
saw unmistakable traces of a peneplain between mountain 
base and the descent to deep water, and in the light of 
their evidence it seemed proper to give a similar interpre¬ 
tation to various features of obscurer character. 
Annette and Gravina islands lie next to the mainland 
in the southern part of the Alexander Archipelago. Out¬ 
side them on the west is the great Prince of Wales Island, 
from which they are separated by a broad channel, 1,500 
to 1,700 feet deep. Each island contains a mountain mass 
bordered on the west by a low foreland, the foreland being 
