Name applied to rocks above the Lower Pennsylvanian Sausbee Formation (new) and unconformably below the Middle Pennsylvanian Atoka Formation. Type area designated as the exposures on west side of Arkansas River near Webbers Falls Reservoir, Muskogee Co, OK. Type sections in sec 34, T13N, R20E. Source of geographic name not stated. Occurs in Muskogee and Cherokee Cos on the Chautauqua platform, and as far east as central Adair and Sequoyah Cos in the Arkoma basin. Varies in thickness due to post-Morrowan, pre-Atokan truncation. Ranges from 19.5 to 22.9 m thick. Consists of 1) a basal limestone and thin interbedded shale named Chisum Quarry Member, 2) a noncalcareous shale called shale "A" member, 3) a wackestone named Greenleaf Lake Limestone Member, and 4) a thin noncalcareous shale called shale "B" member. Contains about equal amounts of limestone and shale near the Arkansas River but changes to predominantly shale eastward. Sandstone occurs mostly as thin lenses. Equivalent to the Dye Shale, Kessler Limestone, and Trace Creek Shale Members of Bloyd Shale to east in OK and AR. Fossiliferous (goniatites, fragments of bryozoans, pelmatozoans, algae). Of Middle Pennsylvanian, late Morrowan age. Cross section. Stratigraphic chart.

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