. . . . "Coal sections, lithologic logs, correlation of composite coal outcrops and generalized section from the Twomile Creek and portions of adjacent Frog Coulee 7 1/2-minute quadrangles, Richland County, Montana"@en . . . . . . "Coal resources of the Twomile creek and portions of adjacent frog coulee 7 1/2-minute quadrangles, Richland county, Montana" . "Coal resources of the Twomile Creek and portions of adjacent Frog Coulee 7 1/2-minute quadrangles, Richland County, Montana"@en . . . . . "Maps"@en . . . "U.S." . .