422 STEPHEN R. CAPPS 
ice covered. The region north and west of Mount McKinley has 
been visited by but one surveying party, whose route, however, lay 
close to the mountains, well within the glaciated area. Brooks™ 
states that ‘‘the position of the northern front of the ice in the 
Kuskokwim basin has not been determined but there is reason to 
believe that it extended as far as Lake Minchumina, or about 30 
miles beyond the mountain front.” The area between Nenana and 
Delta rivers was studied by the writer in 1910,’ and it is believed 
that the northern limit of glaciation as shown on the map for that 
region is not greatly in error. The country east of Delta River 
is still unsurveyed and the ice limit as shown is believed to be only 
an approximation. It is probable that the same factors which are 
responsible for the difference in area of glacial ice on opposite sides 
of the range today and which have already been discussed were 
operative at the time of the great ice advance, and explain the 
lesser development of the northward-moving glaciers at that time. 
EXISTING GLACIERS 
It is not the purpose of this paper to give a detailed description of 
the multitude of glaciers of the Alaska Range, and such a task 
would be impossible in the present state of our knowledge of 
them. Brief descriptions of a few of the more important glaciers 
which have been observed will, however, be given, especially those 
which have been visited by the writer in person, and such facts as 
have a bearing on the recent history of the glaciers, whether they 
seem to be advancing or retreating, will be recorded. 
SUSITNA BASIN 
SKWENTNA DRAINAGE 
Skwentna River has a number of glaciers at the heads of its 
various tributaries, but many of them le in unmapped territory 
and most of them are not of large size. They are sufficiently numer- 
ous and active, however, to keep the river in a turbid state during 
tA. H. Brooks, ‘‘The Mt. McKinley Region, Alaska,’ Prof. Paper U.S. Geol, 
Survey No. 70, 1git, p. 126. 
2S. R. Capps, “‘The Bonnifield Region, Alaska,” Bull. U.S. Geol. Survey No. 501, 
LOn2: 
