Named as a member of Swede Hollow Formation (named) of Cherokee Group of Des Moines Supergroup for town of Oakley in Lucas Co, IA on the Iowa shelf. Type section is in secs 33 and 34, T73N, R22W. Overlies the newly named Whitebreast Coal Member of Swede Hollow. Underlies Ardmore Limestone Member of Swede Hollow. Name Ardmore extended into IA from OK. Lower contact sharp; lower bed 1 ft thick has concentrations of non-skeletal phosphate at base. Lower bed overlain in sequence by 1) bioturbated gray shale, a lithologic type that thickens westward to 3 ft, 2) gray shale with marine fossils, and 3) black shale with chondrites-type burrows. Present also in Clarke, Wayne, Appanoose Cos, IA on Iowa shelf. Cross section. Nomenclature chart. Of Desmoinesian, Pennsylvanian age.

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