The Dunkard Group (Late Pennsylvanian-Early Permian) consists of 400 m of clastic sedimentary rocks with thin limestones and coals that were deposited in deltaic and alluvial-plain environments during the final stages of late Paleozoic sedimentation in the Appalachian basin. Lithofacies indicative of deposition in prograding, tidally influenced, high-constructive deltas dominate the lower Dunkard; these lithofacies are superseded up-section by alluvial-plain lithofacies. The distribution of lithofacies and paleocurrent data indicates that the fluival-deltaic systems prograded northward during deposition of the Dunkard. Sandstones of the Dunkard Group are typically multistory belt sands which were deposited by meandering rivers and highly sinuous delta distributaries.

Petrographic analysis indicates that Dunkard sandstones are immature to submature litharenites derived from a mixed sedimentary, metasedimentary, and volcanic terrane, suggesting a collision orogene provenance related to Alleghenian suturing. Composition of the sandstones is strongly grain-size controlled and depositional environments influenced composition by controlling grain size. Constant composition through the section suggests no major change in source lithology or tectonic regime of the source area during Dunkard deposition.

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