DISTRIBUTION AND CHARACTER OF THE BERING RIVER 
COAL. 
By G. C. Martin. 
INTRODUCTION. 
The following pages contain some of the more important facts of an economic bearing 
brought to light during last season's work in the Bering River coal field. Preliminary 
reports a based on earlier reconnaissance work have already been published. The work 
of the season of 1905 was of a detailed character, including not only careful geologic studies, 
but the preparation of detailed topographic and geologic maps. A final report, to be accom- 
panied by these maps, is in preparation. 
The mining developments of the past year have consisted almost entirely of prospecting, 
of land surveys, and of surveys for railroad connections with tide water. Several important 
tunnels are under construction, but at no point has work progressed far enough to permit 
the mining of coal in commercial quantities, even if transportation were provided. Local 
developments have been held back by the lack of shipping facilities and also by delays in 
securing title to the land. 
EXTENT OF THE FIELD. 
The area of coal-bearing rocks is shown approximately on the accompanying map (fig. 2). 
While the southern limit of the field is known wtth considerable accuracy throughout its 
entire extent, the western boundary is uncertain, appearing to be in part determined by a 
zone of faulting. The coal disappears under the overlying rocks along the northern bor- 
der of the field, where in some places it seems to be cut off by faults, but in other places pre- 
sumably extends for a considerable distance under the overlying rocks and under Martin 
River Glacier. Whether or not the coal is here at such depths and under such conditions 
as would render mining feasible is not known. The eastern termination of the field is not 
known, as it extends beyond the region in which geologic field work has been done. The 
area of coal outcrops is at least 50 square miles. Probably at least 20 square miles more 
are underlain by coal at a greater or less distance below the surface. 
GEOLOGIC SECTIONS. 
The general geologic sequence and the age of the rocks in the Controller Bay region are 
shown in the following table : 
a Petroleum fields of Alaska and the Bering River coal fields: Bull. U. S. Geol. Survey No. 225, L904, 
pp. "365-382. The petroleum fields of Alaska, with an account of the Bering River coal deposits: Bull. 
U. S. Geol. Survey No. 250, 1905. Bering River coal field: Bull. U. S. Geol. Survey No. 250, 1905. pp. 
140-150. 
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