go OS CAK (Ek EGE RS EE, 
consist chiefly of silt, but farther east the ridges seem to be generally 
of coarser material, either modified drift (water-deposited sand and 
gravel) or of till. I did not often land at exposures of the latter, but 
the appearance of bluff faces at many places suggests it. I have no 
doubt that a careful study of this valley would bring to ight moraines 
both terminal and lateral, but the rolling ground moraine seems 
to be the predominant feature of this drift. 
The first decisive evidence of glaciation seen in ascending the 
Kobuk River is ina 150-foot bluff on the north side of the river below 
Squirrel River. As seen from a boat, the bluff appears to consist 
largely of a blue-gray stony clay, at one place resting on bed-rock. I 
landed at the Eskimo village at the mouth of Squirrel River and found 
blue-gray till exposed in the bluff. It abounds in striated stones, in- 
cluding a beautifully glaciated 6-foot boulder. The bank also con- 
tains much sand, probably modified drift. The north bank of the 
river, at a point at which I landed probably about midway between the 
Hunt and Ambler rivers, consists of a very stony till abounding in 
scratched pebbles. The country back of it has a morainic topography. 
In the “Sketch Map of Alaska Showing Glacial Geology” in 
“The Geography and Geology of Alaska,” etc., by Brooks,* published 
in 1906, the glaciated territory of the Endicott Mountain area is 
represented as terminating westward at about the mouth of the Ambler 
River, 173 miles above the mouth of the Kobuk River, and about 130 
miles in a direct line from the drift near the mission on the peninsula. 
This is obviously an error. I traveled in the mountains near the 
Shungnak River, well within the reputed limit of glaciation, and while 
I recognized evidences of glaciation there, these evidences were not as 
pronounced in character as much that I saw in the lower Kobuk and 
Hotham Inlet regions. Similarly, on Seward Peninsula, I found in 
1906 evidences of a more extensive glaciation than had been mapped 
by the U. S. Geological Survey in its preliminary work. I do not 
think that there was a general glaciation of northwestern Alaska, but 
that many of the valleys were occupied by glaciers that ran farther 
than has been indicated on the map mentioned above. 
The Kobuk glacier probably occupied the entire Kobuk Valley. 
It may have been 230 miles long and 15 to 30 miles wide. It was 
tU. S. Geological Survey Publications, Professional Paper, Nv. 45, Pl. XXII. 
