Geologic units in Richmond county, North Carolina

Middendorf Formation (Cretaceous) at surface, covers 55 % of this area

Sand, sandstone, and mudstone, gray to pale gray with an orange cast, mottled; clay balls and iron-cemented concretions common, beds laterally discontinuous, cross-bedding common.

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 13 % of this area

Conglomerate, fanglomerate, sandstone, and mudstone. Conglomerate and fanglomerate shown by pattern.

Pinehurst Formation (Tertiary) at surface, covers 12 % of this area

Sand, medium- to coarse-grained, cross-bedding and rhythmic bands of clayey sand common, unconsolidated.

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

Thin to thick bedded; bedding plane and axial-planar cleavage common; interbedded with metasandstone, metaconglomerate, and metavolcanic rock.

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 4 % of this area

Locally laminated and pyritic; includes phyllonite, sheared fine-grained metasediment, and metavolcanic rock. In Lilesville granite aureole, includes hornfels.

Granitic Rock (Permian/Pennsylvanian) at surface, covers 3 % of this area

Megacrystic to equigranular. Lilesville granite.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 1.0 % of this area

Metamorphosed andesitic tuffs and flows, medium to dark grayish green; minor felsic and mafic metavolcanic rock.

Terrace Deposits and Upland Sediment (Tertiary) at surface, covers 1.0 % of this area

Gravel, clayey sand, and sand, minor iron-oxide cemented sandstone.

Pee Dee Gabbro (Pennsylvanian) at surface, covers 0.7 % of this area

Dark gray to black, medium to fine grained, massive.

Cape Fear Formation (Cretaceous) at surface, covers 0.3 % of this area

Sandstone and sandy mudstone, yellowish gray to bluish gray, mottled red to yellowish orange, indurated, graded and laterally continuos bedding, blocky clay, faint cross-bedding, feldspar and mica common.

Cid Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 0.2 % of this area

(Southwest of Asheboro) Thin to thick bedded; bedding plane and axial-planar cleavage common; interbedded with metasandstone, metaconglomerate, and metavolcanic rock.

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers < 0.1 % of this area

(Located in the Lilesville granite aureole) inequigranular, locally abundant potassic feldspar and garnet; interlayered and gradational with calc-silicate rock, sillimanite-mica schist, mica schist, and amphibolite. Contains small masses of granitic rock.

Peedee Formation - Black Creek Group, undivided (Cretaceous) at surface, covers < 0.1 % of this area

Peedee Formation - Black Creek Group, undivided