Up-dip equivalent of Twiggs Clay, Sandersville Limestone, and Cooper Marl. As mapped, also includes younger clastics of indefinite Late Tertiary age.
Twiggs Clay
As mapped includes Middendorf Formation (Sloan, 1904); "Channel Sands" (LaMoreaux, 1946); Tuscaloosa Formation (Cooke, 1939); and "Huber beds" (Buie, informal terminology)
Granite undifferentiated
Undifferentiated Metavolcanics/ Sericite phyllite/ Meta-argillite/ Quartz mica schist