Geologic units in Yadkin county, North Carolina

Metamorphosed Granitic Rock (Ordovician/Cambrian) at surface, covers 28 % of this area

Equigranular to megacrystic, foliated to massive. Includes Toluca Granite.

Metagraywacke and Muscovite-Biotite Schist (Cambrian/Late Proterozoic) at surface, covers 16 % of this area

Metagraywacke (biotite gneiss) interlayered and gradational with muscovite-biotite schist; minor marble and granitic rock.

Metagraywacke, Amphibolite, and Kyanite Schist (Cambrian/Late Proterozoic) at surface, covers 13 % of this area

Metagraywacke (biotite gneiss) interlayered and gradational with amphibolite and kyanite schist; minor ultramafic and granitic rock.

Metagraywacke (Cambrian/Late Proterozoic) at surface, covers 12 % of this area

Contains quartz and microcline porphyroblasts.

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 10 % of this area

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.

Mica Schist (Cambrian/Late Proterozoic) at surface, covers 6 % of this area

Garnet, staurolite, kyanite, or sillimanite occur locally; lenses and layers of quartz schist, micaceous quartzite, calc-silicate rock, biotite gneiss, amphibolite, and phyllite.

Metamorphosed Mafic Rock (Paleozoic/Late Proterozoic) at surface, covers 4 % of this area

Metagabbro, metadiorite, and mafic plutonic-volcanic complexes.

Granitic Gneiss (Late Middle Proterozoic) at surface, covers 3 % of this area

Megacrystic, in places contains amphibolite.

Newark Supergroup, Dan River Group; Dan River Group, Undivided (Triassic) at surface, covers 3 % of this area

Basin-margin conglomerate and sandstone, red to brown, interfingering with basin-center sandstone and mudstone, green to brown. Conglomerate shown by pattern.

Biotite Gneiss and Schist (Cambrian/Late Proterozoic) at surface, covers 3 % of this area

Inequigranular and megacrystic; 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.

Fine-grained Biotite Gneiss (Cambrian/Late Proterozoic) at surface, covers 1 % of this area

Strongly foliated; minor layers of amphibolite and muscovite schist.

Metamorphosed Gabbro and Diorite (Paleozoic/Late Proterozoic) at surface, covers 0.8 % of this area

Foliated to massive.

Amphibolite (Cambrian/Late Proterozoic) at surface, covers 0.4 % of this area

Metamorphosed mafic extrusive and intrusive rock; includes hornblende gneiss, thin layers of mica schist, calc-silicate rock, and, rarely, marble. Also includes small masses of metadiorite and metagabbro.

Metamorphosed Granitic Rock (Late Proterozoic) at surface, covers 0.4 % of this area

Massive to foliated, locally mylonitic.

Phyllite and Schist (Cambrian/Late Proterozoic) at surface, covers 0.2 % of this area

Includes phyllonite and interlayered biotite gneiss.

Granitic Rock (Permian/Pennsylvanian) at surface, covers < 0.1 % of this area

Megacrystic to equigranular. Churchland Plutonic Suite (Western group) - Churchland, Landis, and Mooresville intrusives.