314 
Glaciation in Northwestern Alaska: PHI S. 
SMITH. 
In northwestern Alaska there are small existing 
glaciers and evidence of much greater alpine gla- 
ciers in the geologic past. The present communi- 
cation aims to set forth some of the observations 
made by parties from the U. S. Geological Survey 
during the field season of 1910 and 1911 in the 
Kobuk and Noatak regions of northwestern 
Alaska, which bear on the glacial phenomena. 
Pre-Wisconsin Glacial Drift in the Region of 
Glacier Park, Montana: Wm. .C. ALDEN. 
Along the east front of the Rocky Mountains 
from Two Medicine Lake northward to the Inter- 
national Boundary, valleys of most of the streams 
issuing from the mountains are bordered on either 
side by high, flat-topped ridges, whose crests stand 
800 to 1,600 feet above the adjacent valley bot- 
toms with maximum elevations ranging from 5,800 
to 6,400 feet above sea level. These high flat- 
topped ridges taken together have the appearance 
of being remnants of a continuous high-level plain 
bordering the base of the bold mountain front and 
they have been so interpreted by Salisbury, Cal- 
houn, Willis and Finley. Examination of nine of 
these ridges, those adjacent to Two Medicine, Cut 
Bank, Boulder, Swift Current and Kennedy 
creeks, and St. Marys and Belly rivers, and of high 
benches at corresponding levels on the west side 
of Belly River, shows the massive ridges to be 
composed of Cretaceous shales and sandstones with 
a capping of glacial drift ranging in thickness 
from 100 to several hundred feet. Fresh scarps 
resulting from recent slumping afford excellent 
exposures of the typical glacial till containing 
abundant striated boulders. In several places 
much of the till is cemented to a hard tillite con- 
glomerate. In some places, as in the type exposure 
of Willis’s ‘‘Kennedy gravels,’’ the material is 
coarse, sub-angular to rounded cobble-stone gravel 
composed principally of quartzite, but even here 
eareful search yielded numerous striated pebbles. 
Striated pebbles and boulders were found on the 
extensive flat top of Milk River Ridge eight miles 
from the mountain front. The component material 
in all cases is derived from the mountains. During 
the last great epoch of glaciation, the glaciers ex- 
tended down nearly all the intervening valleys, in 
some cases nearly filling them. Cut Bank Glacier 
spilled through sags in the crest of Milk River 
Ridge, and St. Marys Glacier laid its lateral 
moraine along the upper slope and lower part of 
SCIENCE 
[N.S. Vou. XXXV. No. 895 
the crest of St. Marys Ridge, but in some places 
the high level drift rises above that of these 
valley glaciers and is quite distinct therefrom, 
though of similar lithological composition. The 
topographic relations, cementation and consider- 
able amount of modification due to weathering 
indicate that the high level drift is much older 
than that in the valleys, and represents a distinct 
and earlier stage of glaciation separated from the 
Wisconsin by a long interval during which much 
erosion was accomplished. Although the relations 
have not yet been carefully studied, it appears 
that this older drift includes some at least of the 
‘‘quartzite gravels’’ described by the authors cited 
above, and regarded as pre-Glacial and possibly, 
but not certainly, some of those described by 
Dawson and McConnell in southern Alberta and 
denominated ‘‘Albertian Drift.’’ 
The paper was discussed by W. W. Atwood and 
A. P. Coleman. 
Some Glacial Deposits Last of Cody, Wyoming, 
and their Relation to the Pleistocene Erosional 
History of the Rocky Mountain Region: WM. J. 
SINCLAIR. 
Twelve miles east of Cody, Wyoming, in the 
Hocene badlands in the vicinity of McCulloch Peak, 
angular blocks of Paleozoic limestone occur at 
elevations of 6,000 feet above sea, either on the 
crests of narrow ridges separating deep valleys cut 
in the badland clays or on terraces several hun- 
dred feet above the Shoshone River. No other 
rocks than limestone have been seen in these high 
level deposits, but at lower levels abundant pebbles 
and boulders of andesite may be found, all of 
which are water worn, while the high level ma- 
terial is highly angular, the only sign of abrasion 
being the pitted surface produced by the solvent 
action of rain water. Corals and bryozoa fre- 
quently appear in relief on the rain-eteched sur- 
faces. Individual fragments vary in size from a 
few inches or less to blocks 6 X 8 X 4 or 5 feet. 
The source of the limestone is, undoubtedly, the 
Paleozoic formations of the mountains to the west 
of Cody. Glacial ice is the only known agent 
capable of transporting blocks of the size indi- 
cated. If they have been transported by ice, 1,200 
feet or more of canyon cutting has intervened 
since their deposition, for they are stranded on 
narrow divides and comb ridges at least that high 
above the Shoshone River. If they are to be cor- 
related with the first glacial advance in the Rocky 
Mountain region, much of the deep dissection of 
such intermontane troughs as the Bighorn Basin 
