Fort Union Formation

(Northwest, Southwest, and Central Wyoming) - Brown to gray sandstone, gray to black shale, and thin coal beds. (East Wyoming) - Light-colored massive sandstone, drab shale, and thick coal beds.
State Wyoming
Name Fort Union Formation
Geologic age Paleocene
Lithologic constituents
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Coal
NGMDB product
Counties Big Horn - Carbon - Fremont - Hot Springs - Johnson - Natrona - Park - Sheridan - Sweetwater - Washakie