TY - RPRT TI - Geologic and structure map, with contours on top of the Pierre Shale, for the north half of the Powder River basin, southeastern Montana and northeastern Wyoming AU - N.M. Denson AU - M.L. Gibson AU - G.L. Sims PY - 1993 DO - 10.3133/i2343a UR - https://pubs.usgs.gov/publication/i2343A ID - i2343A ER -