Geologic units in Lexington county, South Carolina

Black Creek/Cusseta/Blufftown Formations (Cretaceous) at surface, covers 35 % of this area

Moderately to poorly sorted sand and clay deposited in delta-dominated shallow marine environments. Unit is characterized by sands containing locally abundant (F-VC grained) tourmaline and (F-VC grained) muscovite with some monazite and garnet. Clay layers are also common and some lower delta plain deposits form commercial kaolin bodies. Generally very restricted marine in eastern Georgia becoming more open marine to the east and west.

Huber/Lisbon/Barnwell Formations, undivided (Eocene) at surface, covers 14 % of this area

Poorly to well sorted sand, clay and carbonates deposited in delta-dominated fluvial- and open-marine environments. Unit is characterized by commercial kaolin bodies in older strata from westernmost South Carolina to central Georgia. Younger strata are cyclic marine deposits which deeper water facies exposed in western Georgia. Carbonate facies are locally mined in western Georgia for agricultural lime.

Black Mingo/Clayton Formations (Tertiary) at surface, covers 14 % of this area

Poorly to well sorted sand and clay deposited in delta-dominated fluvial- and shallow marine environments. Older parts of unit are characterized by an abundance of feldspar and local sillimanite. Unit is generally delta plain and lagoon deposits in South Carolina becoming open marine calcareous sand and clay in western Georgia. In central Georgia, unit contains an abundance of commercial kaolin deposits formed in lower delta plain environments.

Persimmon Fork Formation (Cambrian to Neoproterozoic) at surface, covers 9 % of this area

Predominately metatuff

Asbill Pond Formation (Middle Cambrian) at surface, covers 7 % of this area

Metamorphosed siltstones and sandstones having interbedded felsic to mafic metavolcanic rocks

Cape Fear/Eutaw Formations (Cretaceous) at surface, covers 7 % of this area

Poorly sorted clayey sand and gravel deposited in delta-dominated fluvial- and restricted marine environments. Unit is characterized by an abundance of smoky quartz gravel, feldspar, monazite, and garnet typically concentrated in placer deposits. Generally non-marine from North Carolina to central Georgia but contains shallow-water delta-front deposits in western Georgia.

Granite - Batesburg (gneissic) pluton (Carboniferous to Permian) at surface, covers 6 % of this area

Granite - Batesburg (gneissic) pluton

Mylonitic rocks of Modoc Fault Zone (Late Paleozoic) at surface, covers 3 % of this area

Mylonite gneiss

Richtex Formation (Ordovician to Middle Cambrian) at surface, covers 2 % of this area

Laminated metamudstone; contains Middle Cambrian or younger sponge spicules

Peedee Formation (Cretaceous) at surface, covers 1 % of this area

Peedee Formation

Alluvial Valley Swamp (Quaternary) at surface, covers 1 % of this area

Unconformable on all underlying units, fluvial sand and gravel at base, grading upwards into fine sands and silts, local peat. May be overrun with recent sediments from forest cutting and agriculture.

Granite - Columbia pluton (Carboniferous to Permian) at surface, covers 0.5 % of this area

Granite - Columbia pluton