Fort Payne Formation

The Fort Payne Formation, or Fort Payne Chert, is a geologic formation found in the southeastern region of the United States. It is a Mississippian cherty limestone that overlies the Chattanooga Shale (or locally the Maury Formation) and underlies the St. Louis Limestone (lower Tuscumbia Limestone in Alabama). To the north, it grades into the siltstone Borden Formation. Eugene Allen Smith named the Fort Payne Formation for outcrops at Fort Payne, Alabama.