182 
ALASKA GLACIERS 
that the ice-sheet of the island was not an overflow from 
the mainland, for mainland ice could not have crossed 
the island without burying deeply the whole northwest 
coast. And the same interpretation may be given to the 
narrow-crested ridge observed between glacial troughs at 
the west, for a strong overriding current would have flat¬ 
tened the crest. The relation of land to sea in Pleistocene 
time is not shown, but remnants of a low base-level plain 
indicate a pre-Pleistocene period of stability, during which 
the attitude of the land was slightly different from the 
present, the eastern side of the island being somewhat 
lower than now. 
The reasoning tending to show that Pleistocene glacia¬ 
tion was associated with a low sea-level applies to the south 
coast of Kadiak with even more force than to the district 
of Prince William Sound, for the island, standing forward 
beyond the general line of the Alaska coast, is specially 
exposed to the influence of the great ocean current. 
REGION OF THE GULF COAST 
Fragmentary as were our observations in the districts 
we have already described, they were still more fragmen¬ 
tary in those touched farther west and north, and the pres¬ 
ent is therefore a convenient point for retrospect and 
summary. The district of the Alexander Archipelago, 
the district of high mountains, the district of Prince Wil¬ 
liam Sound, Kenai Peninsula, and Kadiak Island, circle 
about the Gulf of Alaska. A curved line passing through 
them is more than 1,000 miles in length, and its extremities 
are 900 miles apart. 
In the high mountain region the Pleistocene glacial 
system seems to have included alpine glaciers similar to 
those of the present time but larger; and these united in a 
system of piedmont glaciers, or possibly in a confluent 
piedmont glacier, which everywhere reached the sea. In 
