Named as a member of Caseyville Formation of Morrow Supergroup for exposures at Wyoming Hill, Muscatine Co, IA on the Iowa shelf. Type section is in an escarpment along IA Hwy 22, NE1/4, sec 34, T77N, R1W in Muscatine Co. Two coals assigned to Wyoming Hill at type. Lower coal 0.8 ft thick is shaly and weathered. Upper coal 1.5 ft thick is shaly pyritic and moderately weathered. The two coals are separated by a 1.3 ft thick white, very fine grained ripple bedded sandstone. Lower coal overlies an unnamed gray shale of the Caseyville. Upper coal underlies a dark gray laminated shale with ironstone nodules. Is the upper of two named coal members of the Caseyville. Nomenclature chart. Graphic sections. Of Pennsylvanian, Morrowan age.

Source: GNU records (USGS DDS-6; Denver GNULEX).