Revised in southwestern PA as Waynesburg Formation of Dunkard Group. Includes rocks from base of Waynesburg coal bed to base of Washington coal bed, formerly included as basal part of Washington Formation. Divided into three unnamed members. Thick massive sandstone (formerly Waynesburg Sandstone Member of Monongahela Formation) is dominant lithology in lower member. Several lenticular impure coal beds and patchy fresh-water limestone beds [probably formerly Waynesburg Limestone Member of Monongahela Formation] compose middle member. Persistent plant-bearing sandy siltstone-sandstone unit with thin impure coal (Little Washington coal bed) at its base composes upper member. Thickness about 100 ft. Overlies Uniontown Formation (revised); underlies Washington Formation (revised). Age is Late Pennsylvanian and Early Permian. Waynesburg coal previously dated as Early Permian only based on floral studies by Fontaine and White (1880). Lenticular shales above the coal contain many plant fossils with Permian affinities, but also contain all Pennsylvanian species characteristic of sediments below coal bed. Diagnostic Permian plant form CALLIPTERIS CONFERTA has not been found below Waynesburg coal bed. Report includes correlation chart.

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