Map Showing Principal Coal Beds and Bedrock Geology of the .
WEBApr 23, 2013 · Within the Powder River Basin, both the Wasatch Formation and the Tongue River Member of the Fort Union Formation contain significant coal resources. The map includes loions and elevations of coal beds at 1:50,000 scale for an area that includes ten 7½minute quadrangles covering some 500 square miles.