1. Geologic map showing thickness of the upper Cretaceous Pierre Shale in the north half of the Powder River Basin, southeastern Montana and northeastern Wyoming Author/Creator: Geological Survey (U.S.) Publication/Creation: Denver, CO : For sale by Map Distribution Resource Type: Map Access & Availability: Loading
2. Geologic and structure map of the south half of the Powder River Basin and adjacent areas, northeastern Wyoming Author/Creator: Geological Survey (U.S.) Publication/Creation: Denver, CO : For sale by Map Distribution Resource Type: Map Access & Availability: Loading