In upper Pottsville strata (Pennsylvanian) in the central Appalachians, dominant facies are alluvial-plain sandstones. Flood-plain shales and siltstones intercalated with these sandstones contain numerous coal beds. The coals are laterally discontinuous, but locally thick and may be of interest in continuing development of coal resources of the region. Geometry of coal beds is facies-controlled and in many places may be predicted through interpretations of positions, trends, and geometries of associated facies components.

In a study area covering the Philippi and Weston 15-minute quadrangles in north-central West Virginia, Pottsville strata can be subdivided into (1) a lower interval (average thickness in range of 50-60 m) with relatively lower-energy, mixed-load, coal-poor, alluvial-plain deposits, and (2) an upper interval (average thickness in range of 80 to 100 m) with higher-energy, bed-load, alluvial plain deposits with numerous coal beds, commonly at depths less than 300 m. Lower Pottsville strata in the study area contain multistoried sandstone units that occur in belts averaging 6 to 8 km in width. Individual sandstone units are up to 15 m thick and typically include one or more channel-fill sandstone bodies averaging 6 m thick, as interpreted from geophysical logs. In upper Pottsville strata ultistoried sandstone units occur in belts averaging 8 to 10 km in width. Individual sandstone units are up to 120 ft (36 m) thick, typically containing one or more channel-fill units averaging 8 m thick. Coal beds up to 2 m thick (as interpreted from geophysical logs) intertongue with or terminate against sandstone units. Coals record deposition in flood-basin environments. Coal thickness may be related partly to variable channel positions, differential compaction, and the interaction of regional subsidence and supply of clastics. Future economic development of such coal units should be carefully keyed to an understanding of facies relations.

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