THE ANCIENT KOBUK GLACIER OF ALASKA 
OSCAR H. HERSHEY 
Berkeley, Cal. 
Between Hotham Inlet and Kotzebue Sound, on the Arctic coast 
of Alaska, there is a long narrow strip of rolling upland which is 
probably (in part at least) a glacial moraine. The portion I saw in 
the summer of 1906 (from Cape Blossom north) consists of broad, 
smooth ridges, probably rising 50 to 150 feet above sea-level, bordered 
on the west and north by a sea-cliff from 30 to roo feet high. The 
tundra vegetation on the upland surface completely obscures the 
nature of the underlying material, but its character may be inferred 
from many fairly good exposures in the sea-cliff. 
The northwestern corner of this upland is protected from present 
marine erosion by a triangular strip of lowland bordered by a beach 
ridge from 5 to 12 feet high, behind which there are lagoons 
and marshes. The Friends’ Mission at Kikiktak or Kotzebue Post- 
office is situated on the beach ridge near where it makes a sharp bend 
from north to east and about one and one-half miles from the old 
sea-cliff. The latter, where thus protected, is broken down and 
tundra-covered so that there are no satisfactory exposures of the under- 
lying material. 
About two miles east of the mission, the cliff presents, along a 
distance of half a mile, a number of imperfect exposures of typical 
till. It is a stiff blue-gray clay abounding in rock fragments in sizes 
up to eighteen-inch boulders. They consist of many rock species, 
but varieties of gabbro, probably derived from Mendenhall’s Kanuti 
series,’ are the most conspicuous. Most of the pebbles, cobbles and 
boulders are somewhat rounded, in the manner characteristic of 
glacial abrasion, noticeably differing from similar material after having 
been exposed for some time to wave action on the beach. Very many 
t Walter C. Mendenhall, ‘‘Reconnaissance from Fort Hamlin to Kotzebue 
Sound, Alaska, by Way of Dall, Kanuti, Allen and Kowak Rivers,” U. S. Geological 
Survey, Professional Paper No. to. 
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