TY - RPRT TI - Geologic and structure map, with contours on top of the Pierre Shale, for the south half of the Powder River basin, northeastern Wyoming AU - N.M. Denson AU - M.L. Gibson AU - G.L. Sims PY - 1993 DO - 10.3133/i2343b UR - https://pubs.usgs.gov/publication/i2343B ID - i2343B ER -