Geologic units in Muscogee county, Georgia

Tuscaloosa Formation (Cretaceous) at surface, covers 42 % of this area

Tuscaloosa Formation

Biotite Gneiss (Precambrian-Paleozoic) at surface, covers 19 % of this area

Biotite gneiss

Stream alluvium (Quaternary) at surface, covers 14 % of this area

Stream alluvium and undifferentiated terrace deposits

Hornblende Gneiss/ Amphibolite/ Granite Gneiss (Precambrian-Paleozoic) at surface, covers 9 % of this area

Hornblende Gneiss/ Amphibolite/ Granite Gneiss

Eutaw Formation (Cretaceous) at surface, covers 6 % of this area

Eutaw Formation

Biotite Gneiss/ Amphibolite (Age uncertain) at surface, covers 5 % of this area

Biotite Gneiss/ Amphibolite

Granitic Gneiss undifferentiated (Precambrian-Paleozoic) at surface, covers 3 % of this area

Granitic Gneiss undifferentiated

Hornblende Gneiss/ Amphibolite (Precambrian-Paleozoic) at surface, covers 2 % of this area

Hornblende Gneiss/ Amphibolite

Mylonite and ultramylonite (Age uncertain) at surface, covers 0.6 % of this area

Mylonite and ultramylonite

Alluvial, coastal and low terrace deposits (Holocene) at surface, covers 0.4 % of this area

Varicolored fine to coarse quartz sand containing clay lenses and gravel in places. Gravel composed of quartz and chert pebbles and assorted metmorphic and igneous rock fragments in streams near the Piedmont. In areas of the Valley and Ridge province gravel composed of angular to subrounded chert, quartz, and quartzite pebbles. Coastal deposits include fine to medium quartz sand with shell fragments and accessory heavy minerals along Gulf beaches and fine to medium quartz sand, silt, clay, peat, mud and ooze in the Mississippi Sound, Little Lagoon, bays, lakes, streams, and estuaries.

Uchee Complex; Phenix City Gneiss (Precambrian to Paleozoic) at surface, covers 0.2 % of this area

Biotite-epidote quartz diorite gneiss and biotite-hornblende gneiss; locally includes migmatitic amphibolite; cut by numerous granitic veins.

Motts Gneiss (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Leucocratic quartz-rich quartz diorite pencil gneiss.

Motts Gneiss, Unnamed unit (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Unnamed unit comprised of masses of epidote-hornblende-oligoclase mylonitic gneiss and amphibolite.

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Blastomylonite, mylonite gneiss, locally includes mylonite schist and mylonite quartzite in Towaliga fault zone.