Geologic units in Montgomery county, North Carolina

Uwharrie Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 30 % of this area

(At Asheboro and to south) Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Tillery Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 19 % of this area

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

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 18 % of this area

Metamorphosed argillite, mudstone, volcanic sandstone, conglomerate, and volcanic rock.

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 11 % of this area

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

Middendorf Formation (Cretaceous) at surface, covers 8 % 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.

Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

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

Cid Formation; Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

(Southwest of Asheboro) Metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 2 % of this area

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

Pinehurst Formation (Tertiary) at surface, covers 2 % of this area

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

Floyd Church Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 1 % of this area

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

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 1 % of this area

Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Cid Formation; Metamudstone and Meta-Argillite (Cambrian/Late Proterozoic) at surface, covers 1 % of this area

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

Cid Formation; Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 0.8 % of this area

(Southwest of Asheboro) Metamorphosed dacitic to rhyolitic flows and tuffs, light gray to greenish gray; interbedded with mafic and intermediate metavolcanic rock, meta-argillite, and metamudstone.

Yadkin Formation (Cambrian/Late Proterozoic) at surface, covers 0.7 % of this area

Metamorphosed graywacke, volcanic sandstone, and siltstone; interbedded with mafic and intermediate metavolcanic flows and tuffs.

Mafic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 0.4 % of this area

Metamorphosed basaltic flows and tuffs, dark green to black; interbedded with felsic and intermediate metavolcanic rock and metamudstone.