Geologic map showing thickness of the upper Cretaceous Pierre Shale in the north half of the Powder River basin, southeastern Montana and northeastern Wyoming

I-2380-A Geologic map showing thickness of the upper Cretaceous Pierre Shale in the north half of the Powder River basin, southeastern Montana and northeastern Wyoming, scale 1:200,000, 1993, ISBN 978-0-607-79547-9 Keywords: Powder river basin, Stratigraphic Geology, Stratigraphy, Geologic maps, Sedimentology, Sedimentary and carbonate rocks