Ordovician plays within the Cumberland Plateau has been explored for over a century with only moderate success... -Most developed fields are in Mississippian limestones -Knox, Stones River, and Nashville Groups have only been cursorily explored in the region -Hydrocarbon discoveries in the Rose Hill (SW VA) and Swan Creek fields (NE TN) indicate Ordovician rocks should be further explored -Source of the these hydrocarbons is the Ordovician rocks (gas chromatography by R. Burruss, USGS)