Seven sedimentary facies are recognized within the lower members of the Pottsville Group (Pennsylvanian) in southern Ohio which define an overall onlap-offlap sequence. The facies succession, as defined by stratigraphic lithofacies analysis, begins with coarse clastic braided and meandering stream deposits suggesting an aggrading coastal plain depositional environment. The braided-stream facies comprises medium to coarse-grained quartzarenite and pebble to cobble conglomerate and disconformably overlies Lower Mississippian formations. Contained large-scale planar and some trough cross-bedding yield strongly unimodal (west) paleocurrent directions. The overlying meandering stream facies consists of multistoried fining-upward sequences of sandstone, minor conglomerate, silt tone, shale, and coal. Lacustrine and interdistributary bay facies are interpreted to represent a transitional environment from a low-lying coastal plain to a northward transgressing marine embayment. Varvelike laminae of mudstone and claystone of the lacustrine facies grade upward to marine-fossil bearing interdistributary bay and fine delta front facies. Subsequent southerly progradation of a delta system is indicated by interdistributary bay, delta front, crevasse splay, and distributary channel facies.

Fossil plant assemblages suggest that the lower Pottsville Group, in southern Ohio, is entirely Morrowan (Namurian C-Westphalian A) New River Formation age-equivalent.

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