Pennsylvanian rocks generally underlie the Cumberland Plateau and Warrior plateau. To the south and west they continue beneath Mesozoic sediments of the Coastal Plain. To the north they form the Allegheny plateau.

Lithologically, the strata consist of sandstone, shale, conglomerate, coal, underclay, and minor ironstone and limestone. Black shale is prominent in western Mississippi.

Geology of the Pennsylvanian is illustrated by five correlation sections, four isopach and lithofacies maps, and three structure maps.

Deposition began during the early Pottsville in two separated areas and then spread by basal onlap beyond the present day erosional limits. By middle Pottsville time, Pennsylvanian deposits were continuous with those of the Eastern Interior basin. Thickest connection was probably across the Clifton saddle in western Tennessee, and even the Nashville dome was covered.

Trends of deposition were generally parallel to the Cincinnati arch, swinging from northeast in Kentucky and Tennessee to northwest in Mississippi, as the arch similarly swings to join the Ozark dome.

Pennsylvanian rocks were later folded and thrust in southwest-trending "no-basement" structure of the Appalachian revolution. This structure system may intersect or join with northwest-trending Ouachita structure deep in the subsurface in southeast Mississippi.

More recent epeirogenic movements have formed a broad southeast-plunging nose in southern Tennessee and northern Alabama where Pennsylvanian beds have been most deeply eroded.