138 ALASKAN MINERAL RESOURCES IN 1906. 
disappearance of such ice unless it was present at a time very much 
earlier than the recent glaciation mentioned above. 
Closer study of the region, however, especially of the distribution 
of gravels, has led to the observation of phenomena which are most 
easily explained as being due to ice action, and it may be that in 
valleys like that of Nome River ice streams from the Kigluaiks 
approached much nearer the coast than has heretofore been supposed. 
Since the evidence against a mantling ice sheet appears to be con- 
clusive, it is altogether improbable that the tundra deposits have 
been affected in more than a minor degree by glacial ice except in the 
form of floating ice, for there are no known centers of local accumu- 
lation near the coast. 
ECONOMIC GEOLOCxY. 
The progress in mining on Seward Peninsula has been presented 
from time to time in various publications of the Survey, and since this 
present form of report was adopted an account of each season's work 
has been published yearly. The economically important deposits 
may be divided into two classes — lode and placer deposits. 
LODE DEPOSITS. 
Some generalizations concerning the occurrence of veins have 
already been given and it now remains to describe in greater detail ai 
few particular localities which have attracted some attention during 
the last year. 
BISMUTH. 
For a number of years bismuth has been known to be present on 
Charley Creek, a tributary of Sinuk River from the south. It was 
first found in the sluice boxes at the lower end of the creek, and later 
the float was discovered farther up and traced to its source. On the 
east branch of Charley Creek, at a point about 1,000 feet from the 
forks and at an elevation of 950 feet above sea level, two parallel 
quartz veins appear near the stream bed and have been found to 
carry the bismuth. These veins are about 12 inches and 8 inches in; 
thickness and are separated by 16 to 18 inches of schist. They occur 
in strike joints dipping 50° to 60° N., and may be traced on the surface 
for only a short distance because of the covering of loose slide rock. 
At one place they are offset about 8 to 10 inches by a small fault. The 
percentage of bismuth seen in the veins is small, but some bowlders 
found in the stream below show a larger amount. Attempts to inter- 
est capital in the development of these veins have not been successful 
and up to the present time little has been done toward prospecting 
them. 
