ANCIENT KOBUK GLACIER OF ALASKA 87 
depressions were produced by the melting of large residual masses of 
glacial ice buried under the silt. I saw a similar bluff in looking 
over the country back of Cape Blossom. 
There is nothing in the topography of the peninsula to suggest the 
direction of ice movement except that the ridges are prevailingly 
elongated easterly and westerly. These ridges, in so far as they are 
above sea-level, consist chiefly of silt, but, as we have seen, cores of 
boulder clay usually appear where they are bisected by the sea-cliff in 
a manner to indicate that the present topography is in large part con- 
trolled by the surface of the glacial deposit. The topography is not 
that typical of a terminal or lateral moraine but of a fluted ground 
moraine. All the till exposures examined corroborate the idea that it 
is ground moraine. Therefore, I incline to the opinion that these 
ridges are approximately parallel to the direction of ice movement 
like the major axis of a drumlin. Indeed, many of the shorter ridges 
approximate to the drumlin form, and if the silt covering were removed 
this form might be even more pronounced. Probably the ice that 
glaciated this country was a great glacier that came out of the broad 
valley of the Kobuk River on the east and extended into the Arctic 
Ocean. Mendenhall says: 
All of the peninsula which separates Hotham Inlet and Selawik Lake from 
Kotzebue Sound and its waters, with the exception of the extreme southwestern 
point (where members of the schistose series outcrop in Choris Peninsula), 
is made up of Pleistocene silts, clays, and embedded ice. Its outline and topog- 
raphy suggest that shoals which have formed off the mouths of the Noatak, 
the Kowak, the Selawik, and the Buckland have been raised into islands by 
slight local elevations, and that these islands have afterwards been tied into one 
long peninsula by the action of winds, waves, and currents.? 
On the contrary, my investigation of that broad portion of the 
peninsula lying north of the latitude of Cape Blossom has led 
to the conclusion that it is a remnant of an undulating silt-covered 
drift plain into which the sea has cut on the western, northern, 
and eastern sides, producing a cliff from 30 to roo feet high. The 
generally undissected character of the upland and the fresh appearance 
of the till suggest a late stage of glaciation presumably Wisconsin. 
This opinion is expressed with the fact in mind that erosion and 
weathering standards of the Temperate Zone are not applicable here 
t U.S. Geological Survey Professional Paper No. 10, p. 45. 
