Geologic units in McDuffie county, Georgia

Granitic Gneiss undifferentiated (Precambrian-Paleozoic) at surface, covers 26 % of this area

Granitic Gneiss undifferentiated

Lower Tertiary-Cretaceous undifferentiated (Lower Tertiary-Cretaceous) at surface, covers 22 % of this area

As mapped includes Middendorf Formation (Sloan, 1904); "Channel Sands" (LaMoreaux, 1946); Tuscaloosa Formation (Cooke, 1939); and "Huber beds" (Buie, informal terminology)

Granite undifferentiated (Precambrian-Paleozoic) at surface, covers 13 % of this area

Granite undifferentiated

Granite Gneiss/ Amphibolite (Precambrian-Paleozoic) at surface, covers 10 % of this area

Granite Gneiss/ Amphibolite

Sericite Schist (Precambrian-Paleozoic) at surface, covers 10 % of this area

Sericite Schist

Meta-argillite/ Sericite phyllite/ Metavolcanics (Precambrian-Paleozoic) at surface, covers 5 % of this area

Meta-argillite/ Sericite phyllite/ Metavolcanics

Irwinton Sand (Eocene) at surface, covers 5 % of this area

Up-dip equivalent of Twiggs Clay, Sandersville Limestone, and Cooper Marl. As mapped, also includes younger clastics of indefinite Late Tertiary age.

Sericite Schist/ Amphibolite/ Granite gneiss (Precambrian-Paleozoic) at surface, covers 3 % of this area

Sericite Schist/ Amphibolite/ Granite gneiss

Felsic Metavolcanics (Precambrian-Paleozoic) at surface, covers 3 % of this area

Felsic Metavolcanics

Meta-argillite/ Phyllite (Precambrian-Paleozoic) at surface, covers 2 % of this area

Meta-argillite/ Phyllite

Twiggs Clay (Eocene) at surface, covers 1 % of this area

Twiggs Clay

Amphibolite/ Biotitic Gneiss/ Quartz Sericite Schist (Precambrian-Paleozoic) at surface, covers 0.4 % of this area

Amphibolite/ Biotitic Gneiss/ Quartz Sericite Schist

Quartz Sericite Schist/ Biotitic Gneiss (Precambrian-Paleozoic) at surface, covers 0.3 % of this area

Quartz Sericite Schist/ Biotitic Gneiss

Quartzite/ Mica Schist (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area

Quartzite/ Mica Schist