Name Perth limestone member of Brazil formation proposed for marine unit that closely overlies Minshall coal. Numerous references have been made to this limestone and Wanless (1939) referred to it as Minshall limestone. Name Minshall is herein abandoned. At type locality, limestone is gray, hard, argillaceous, and fossiliferous. Weathers brown. Thickness 6.3 ft. Member lies 0.2 ft to 15 ft above Minshall coal and 3 to 15 ft below Coal II, which lies near top of the Brazil formation. Age is Middle Pennsylvanian.

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

Physical correlation indicates that the type Perth Limestone Member (Staunton Formation) of northern Clay Co., IN, is equivalent to the Lewisport Limestone in KY. The Lewisport, in turn, is equivalent to the Curlew Limestone Member. Correlations have been confirmed by faunal evidence. The Perth/Curlew is composed of one or more limestone beds that intergrade laterally with shale and siltstone containing marine fossils.

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