Geologic units in Durham county, North Carolina

Newark Supergroup, Chatham Group; Chatham Group, Undivided (Triassic) at surface, covers 63 % of this area

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

Felsic Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 20 % 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.

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers 7 % of this area

Megacrystic, well foliated; locally contains hornblende. Chapel Hill, Chatham, Farrington, Meadow Flats, Mt. Moriah, Parks Crossroads plutons, and Roxboro and Vance County suites.

Intermediate Metavolcanic Rock (Cambrian/Late Proterozoic) at surface, covers 5 % of this area

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

Newark Supergroup, Chatham Group; Diabase (Jurassic) at surface, covers 3 % of this area

Diabase - dikes and sills, gray to black.

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 0.7 % of this area

Foliated to massive.

Metavolcanic-Epiclastic Rock (Cambrian/Late Proterozoic) at surface, covers 0.6 % of this area

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

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 0.3 % of this area

Foliated to massive.