Ordovician Bentonites in Tennessee and Adjacent States

Altogether, fifteen beds of bentonite have been recognized in the Ordovician from the lower Stones River group to the lower Maysville. Formerly, it was thought that the Ordovician volcanic activity started in Lowville time and ceased in Trenton time, but beds of bentonite in this area have been recognized strati-graphically far below and above these horizons. Two thick beds of bentonite can be recognized with certainty throughout the western half of the Appalachian Valley from northwestern Georgia and northeastern Alabama to southwestern Virginia.