Middle Miocene marine diatoms from the Hawthorn Formation within the Ridgeland Trough, South Carolina and Georgia

Diatomaceous sediments in outcrops of the Miocene Hawthorn Formation at Dawsons Landing in South Carolina and at Berrys Landing in Georgia, have yielded a total of 111 marine diatom taxa. Varving of the diatomaceous clay suggests that the diatoms were deposited in a restricted basin or lagoonal area that had oxygen-deficient bottom waters. The Middle Miocene diatom assemblage of the Hawthorn is correlative with that of approximately the upper half of Miocene Lithologic Unit 16 of the Choptank Formation in the Chesapeake Bay region of Maryland and with the Serravallian Stage.