Geologic units in Jones county, Georgia

Biotite Granite Gneiss/ Feldspathic Biotite Gneiss/ Amphibolite Hornblende Gneiss (Precambrian-Paleozoic) at surface, covers 57 % of this area

Biotite Granite Gneiss/ Feldspathic Biotite Gneiss/ Amphibolite Hornblende Gneiss

Lower Tertiary-Cretaceous undifferentiated (Lower Tertiary-Cretaceous) at surface, covers 13 % of this area

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

Biotite Gneiss (Precambrian-Paleozoic) at surface, covers 7 % of this area

Biotite gneiss

Granite Gneiss/ Amphibolite (Precambrian-Paleozoic) at surface, covers 5 % of this area

Granite Gneiss/ Amphibolite

Hornblende Gneiss/ Granite Gneiss/ Biotite Gneiss (Precambrian-Paleozoic) at surface, covers 4 % of this area

Hornblende Gneiss/ Granite Gneiss/ Biotite Gneiss

Twiggs Clay (Eocene) at surface, covers 4 % of this area

Twiggs Clay

Hornblende Gneiss/ Amphibolite (Precambrian-Paleozoic) at surface, covers 4 % of this area

Hornblende Gneiss/ Amphibolite

Granitic Gneiss undifferentiated (Precambrian-Paleozoic) at surface, covers 1 % of this area

Granitic Gneiss undifferentiated

Granite Gneiss/ Granite (Precambrian-Paleozoic) at surface, covers 1 % of this area

Granite Gneiss/ Granite

Granite undifferentiated (Precambrian-Paleozoic) at surface, covers 0.8 % of this area

Granite undifferentiated

Irwinton Sand (Eocene) at surface, covers 0.8 % 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.

Biotite Gneiss/ Mica Schist (Age uncertain) at surface, covers 0.5 % of this area

Biotite Gneiss/ Mica Schist

Amphibolite (Precambrian-Paleozoic) at surface, covers 0.5 % of this area

Amphibolite

Hornblende Gneiss/ Amphibolite/ Granite Gneiss (Precambrian-Paleozoic) at surface, covers 0.1 % of this area

Hornblende Gneiss/ Amphibolite/ Granite Gneiss

Mylonite and ultramylonite (Age uncertain) at surface, covers < 0.1 % of this area

Mylonite and ultramylonite

Mafic Hornfels (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area

Mafic Hornfels