The Chattanooga Shale is a geological formation in Alabama, Arkansas, Georgia, Kansas, Kentucky, Missouri and Tennessee.

It is usually interpreted as dark fibrous shale made from finely fragmented silt and clay sand blown onto ancient sea beds.

Such systems span Cambrian to Pennsylvanian intervals, and the Chattanooga Shale feeds much of the Appalachian Basin's oil and gas.

A limestone directly beneath the Mississippian carbonate boundary has been a leading factor used to help identify surface exposures in the region.

The middle shale fraction has a high TOC level, as a result it is one of the most significant geologic units in the Appalachian Basin petroleum chains.

It acts as a reservoir for a massive number of hydrocarbons, and a good supply of that gas comes from the rocks, particularly in Kentucky, Tennessee, and West Virginia.