In the Bighorn Basin consists of Lance, Meeteetse and, in the southeastern part, tongue of Lewis Shale; in the northern part of the Wind River Basin, of Lance, Meeteetse, and Lewis, and, in the southeastern part of the basin, of Lance and Lewis; on the west side of the Powder River Basin north of T. 45 N., of Lance, Fox Hills, and Bearpaw, and, to the south, of Lance, Fox Hills, and Lewis. Lance Formation - Thick-bedded buff sandstone and drab to green shale; thin conglomerate lenses. Fox Hills Sandstone - Light-colored sandstone and gray sandy shale containing marine fossils. Meeteetse Formation - Chalky-white to gray sandstone, yellow, green, and dark-gray bentonitic claystone, white tuff, and thin coal beds. Bearpaw Shale - Dark-greenish-gray shale containing thin gray sandstone partings. Lewis Shale - Gray marine shale containing many gray and brown lenticular concretion-rich sandstone beds.