The Rushville Shale is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

. It dates back to the

Mississippian Mississippian may refer to: * Mississippian (geology), a subperiod of the Carboniferous period in the geologic timescale, roughly 360 to 325 million years ago * Mississippian cultures, a network of precontact cultures across the midwest and Easte ...

References

Generalized Stratigraphic Chart for Ohio
Carboniferous Ohio Shale formations of the United States Geologic formations of Ohio {{ohio-geologic-formation-stub