TY  - RPRT
TI  - Geologic map showing thickness of the upper Cretaceous Pierre Shale in the south half of the Powder River Basin, northeastern Wyoming and adjacent areas
AU  - M.L. Gibson
AU  - G.L. Sims
PY  - 1993
DO  - 10.3133/i2380b
UR  - https://pubs.usgs.gov/publication/i2380B
ID  - i2380B
ER  -