Paleozoic rocks range in thickness from 2,800 ft (850 m) near the crest of the Findlay arch to 13,000 ft (3,960 m) at the Ohio end West Virginia border. All systems of the Paleozoic Era are present. Regional dip on top of the monoclinal basement structure is east and southeast, increasing from 40 ft (12 m) per mile in central Ohio to 150 ft (45 m) per mile in southeastern Ohio.

Oil and gas are produced from rocks in all Paleozoic systems except the Permian. Most present oil and gas production is from stratigraphic traps in the Silurian sandstones of eastern Ohio and from Cambrian dolomite in the shallow Appalachian basin of central Ohio. Pennsylvanian., Mississippian, and Devonian rocks will continue to be explored but will not add significantly to reserves. New Silurian "Clinton" fields will be found, as indicated by the recent (1968) discovery of the Claysville field in Guernsey County.

Cambrian-Ordovician strata in the deeper pert of the basin of eastern Ohio are relatively unexplored and have the greatest potential for adding to reserves. The increasing volume of geophysical and geological information should aid in discovery of the deeper stratigraphic and structural traps believed to be present in the area.