martin.] COAL IN CONTROLLER BAY REGION. 27 
Occurrence of the petroleum. — There arc said to be good seepages 
in several of the creeks in this belt, and the petroleum is regarded as 
similar in character to that of the Controller Bay Held. It oozes 
from the rocks along the crest of the anticline. No development 
work has been done, due to the difficulty of transporting machinery, 
which it would be necessary either to land through the surf on the 
open coast or to transport overland for a distance of 75 miles from 
Controller Bay. The latter will be an impossibility until roads are 
constructed. 
COAL. 
BERING RIVER COAL FIELD. 
The -field. — The Bering River coal field lies from 12 to 25 miles 
inland from Controller Bay. The coal area, as far as known, is 
restricted to the region north of Bering Lake and Bering River, 
Its southern boundary appears to coincide approximately with the 
position of Bering Lake and with Bering River above the lake. The 
western boundary, although not definitely known, is assumed to lie 
along a north-south line extending through the northwest arm of 
Bering Lake parallel to its western shore. The northern and east- 
ern boundaries are also uncertain, but are probably at a considerable 
distance beyond the region as now known. The coal area as at 
present recognized includes about 120 square miles. (See PL III.) 
The coal is known to extend as far north as the Martin River 
Glacier and as far east as the valley east of Carbon Mountain. It is 
possible that further exploration will reveal the presence of coal 
north of the Martin River Glacier in the foothills of the Chugach 
Mountains or in the region to the east of Carbon Mountain. 
The lowlands which border the northeast shore of Bering Lake 
and extend up Shepherd Creek, Bering River, and other streams are 
doubtless underlain by coal. The covering of mud and other soft 
deposits is probably very thick, and the uncertainties of deep mining 
below it are so great that these lands are now of very doubtful value. 
The same applies to the area covered by the Bering, Martin River, 
and Kushtaka glaciers. The above estimates of the coal area include 
only the high land lying above and between the tidal flats and river 
flats and the glaciers. 
Geologic occurrence of the coal. — The coal is restricted to the rocks 
of the Kushtaka formation described above. The following local 
sections have been measured by the writer : 
i & 
Section in lower tunnel on cast bank of Carbon Greek. 
Feet. 
Hark shale 2 
Coal 2<) 
Massive, arkosic, cross-bedded sandstone with many thin carbonaceous 
streaks-.,-^ ______„ 10 
