The "B" Zone of Calvert (1962: OH G.S. Rept. Inv. 45) is here formally designated the Steam Corners Member of the Copper Ridge Dolomite. The Copper Ridge is assigned to the Lee Valley Group of the Knox Supergroup. The new member is known only from the subsurface of northern OH and is described as a series of glauconitic, quartzose dolomites and a basal sandstone, the informal Krysik sandstone facies. The description of the type log in Morrow Co. is from Janssens (1973: OH Geol. Survey Bull. 64). The Steam Corners is 55 ft thick at this locality and reaches a maximum 250 ft in the Huron-Lorain Swale, a broad syncline between the Findlay and Wooster arches. Unit can be recognized by its distinctive lithological and geophysical log character as far east as Guernsey Co., OH, and as far west as Wood Co., OH. It has a high gamma ray signature and a medium to high neutron response and contains an important petroleum reservoir. The Steam Corners lies between what are here called the Upper and Lower Copper Ridge Dolomites, and was probably deposited in a prodeltaic or offshore marine environment. Age is Late Cambrian.

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