02a0008775;20011205d1986 ekmy0engy01;eng;a z 000yy;r;Mineral resource potential and geology of the Black Hills National Forest, South Dakota and Wyoming;E. Dewitt ... et al;Wash.;U.S. Government Printing Office;1986;135 p.;4 maps;Bulletin;U.S. Geological Survey;no.1580;2001b;aBulletin ; fU.S. Geological Survey ; vno.1580;a464.2;Dewitt;E.;101;436950;P;254.2;B87;v1580 ; r455.00;a02;b1;cP