Geologic units in Virginia (state in United States)

Mineral Resources On-Line Spatial Data

Falmouth Intrusive Suite (Mississippian - Pennsylvanian) at surface, covers < 0.1 % of this area

Falmouth Intrusive Suite - Granite, quartz monzonite, granodiorite, and tonalite

Lithology: granite; quartz monzonite; granodiorite; tonalite

Charnockite (Proterozoic Y) at surface, covers 0.7 % of this area

Charnockite.

Lithology: granitic gneiss

Chemung Formation (redefined as Foreknobs Formation) (Devonian) at surface, covers 1 % of this area

Chemung Formation - Shale and sandstone with a few thin, quartz-pebble conglomerates and red-beds.

Lithology: shale; sandstone; conglomerate

Conococheague Formation (Cambrian-Ordovician) at surface, covers 1 % of this area

Conococheague Formation - Limestone, dolomite, and calcareous sandstone.

Lithology: limestone; dolostone (dolomite); sandstone

Migmatitic Paragneiss (Proterozoic) at surface, covers 0.8 % of this area

Migmatitic paragneiss.

Lithology: paragneiss

Mylonite, Mylonite Gneiss, and Cataclastic Rocks (Proterozoic - Paleozoic ?) at surface, covers 1 % of this area

Mylonite, mylonite gneiss, and cataclastic rocks.

Lithology: mylonite; gneiss; cataclastite

Gneiss (Proterozoic) at surface, covers < 0.1 % of this area

Gneiss as exotic blocks within melange units

Lithology: gneiss

Conococheague Formation (Cambrian) at surface, covers 0.4 % of this area

Conococheague Formation - Limestone, dolomite, and calcareous sandstone.

Lithology: limestone; dolostone (dolomite); sandstone

Porphyroblastic Garnet-Biotite Gneiss (Proterozoic Y) at surface, covers 2 % of this area

Porphyroblastic garnet-biotite gneiss.

Lithology: biotite gneiss

Bacons Castle Formation (Tertiary) at surface, covers 3 % of this area

Bacons Castle Formation - Gravel grading upward into sand and sandy clayey silt

Lithology: gravel; sand; silt; clay or mud

Garrisonville Mafic Complex (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Garrisonville Mafic Complex - Metamorphosed mafic and ultramafic rocks

Lithology: amphibolite; hornblendite; greenstone

Fork Mountain Formation (Proterozoic Z-Cambrian) at surface, covers 2 % of this area

Fork Mountain Formation - Quartzose mica schist, garnet-biotite gneiss, calc-silicate quartzite, and melange.

Lithology: mica schist; gneiss; quartzite; melange

Interlayered Mafic and Felsic Metavolcanic Rocks - Quartzofeldspathic biotite gneiss (Cambrian) at surface, covers 2 % of this area

Interlayered Mafic and Felsic Metavolcanic Rocks - Quartzofeldspathic biotite gneiss

Lithology: biotite gneiss; schist; intermediate volcanic rock

Potomac Formation (Cretaceous) at surface, covers 0.4 % of this area

Potomac Formation - Pebbly, poorly sorted quartzo-feldspathic sand interbedded with sandy clay and silt; minor organic-rich clay and silt

Lithology: sand; clay or mud; silt

Frederick Limestone (Cambrian) at surface, covers < 0.1 % of this area

Frederick Limestone - Limestone.

Lithology: limestone

Mafic Volcanic Rocks (Proterozoic Z) at surface, covers < 0.1 % of this area

Mafic volcanic rocks.

Lithology: mafic metavolcanic rock; phyllite; metasedimentary rock

Newark Supergroup; Triassic Sandstone, Siltstone, Shale, and Coal (Triassic) at surface, covers < 0.1 % of this area

Interbedded sandstone, siltstone, shale and coal

Lithology: sandstone; siltstone; shale; coal

Newark Supergroup; Triassic shale and siltstone (Triassic) at surface, covers 0.6 % of this area

Interbedded shale and siltstone

Lithology: shale; siltstone

Catoctin Formation - Metabasalt (Proterozoic Z-Cambrian) at surface, covers 2 % of this area

Catoctin Formation - Metabasalt.

Lithology: meta-basalt

Newark Supergroup; Conglomerate, mixed clasts (Upper Triassic) at surface, covers 0.2 % of this area

Conglomerate, mixed clasts

Lithology: conglomerate

Martinsburg Formation (Ordovician) at surface, covers < 0.1 % of this area

Martinsburg Formation - predominantly gray to dark shale, yellowish in the upper portion. Contains scattered thin limestone and sandstone interbeds, particularly in the lower portion. The upper portion constitutes the Reedsville Shale.

Lithology: shale; limestone; sandstone

Alligator Back Formation; Mica schist and phyllite (Late Proterozoic) at surface, covers < 0.1 % of this area

Mica schist and phyllite - laminated to thin layered; interlayered with minor biotite-muscovite gneiss and amphibolite.

Lithology: mica schist; phyllite; gneiss; amphibolite

Biotite-Muscovite Leucogranite Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Biotite-muscovite leucogranite gneiss

Lithology: granitic gneiss

Lynchburg Group - Conglomerate and metagraywacke (Proterozoic Z) at surface, covers < 0.1 % of this area

Lynchburg Group - Conglomerate and metagraywacke.

Lithology: conglomerate; metasedimentary rock

Muscovite Schist and Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Muscovite schist and gneiss

Lithology: gneiss; mica schist

Beekmantown or Lower Ordovician Group (Ordovician) at surface, covers < 0.1 % of this area

Beekmantown or Lower Ordovician Group - mainly thick-bedded limestone and dolomite. Various units produce much chert on outcrop. Consists of units: Pinesburg Station Dolomite, Rockdale Run Formation, and Stonehenge Limestone.

Lithology: limestone; dolostone (dolomite); chert

Windsor Formation (Tertiary-Quaternary) at surface, covers 3 % of this area

Windsor Formation - Interbedded gravel, sand, silt, and clay; at altitudes to 85-95 ft. (top of unit).

Lithology: gravel; sand; silt; clay or mud

Shirley Formation (Quaternary) at surface, covers 1 % of this area

Shirley Formation - Interbedded gravel, sand, silt, clay, and peat; at altitudes to 35-45 ft. (top of unit).

Lithology: gravel; sand; silt; clay or mud; peat

St. Paul Group (Ordovician) at surface, covers < 0.1 % of this area

St. Paul Group - includes the New Market and Row Park Limestones. Predominantly medium-gray aphanitic limestone, containing very low-silica, cream-colored member of considerable economic importance. Chert nodules and dolomite occur in the Row Park.

Lithology: limestone; chert; dolostone (dolomite)

Marsh and Intertidal Mud Deposits (Quaternary) at surface, covers 0.6 % of this area

Marsh and Intertidal Mud Deposits - Organic-rich clay and silt

Lithology: clay or mud; silt

Maccrady Shale (Mississippian) at surface, covers < 0.1 % of this area

Maccrady Shale - Dusky-red and green shale and mudstone; and evaporite deposits.

Lithology: shale; siltstone; evaporite; limestone; mudstone; sandstone

New River Formation (Pennsylvanian) at surface, covers 0.3 % of this area

New River Formation - Sandstone, siltstone, shale, and coal.

Lithology: sandstone; siltstone; shale; coal; limestone

Lynchburg Group; Charlottesville Formation (Proterozoic Z) at surface, covers 0.3 % of this area

Lynchburg Group; Charlottesville Formation - Graphitic metasiltstone, feldspathic metasandstone, and quartzite.

Lithology: meta-argillite; sandstone; quartzite; phyllite; slate

Konnarock Formation (Proterozoic Z) at surface, covers < 0.1 % of this area

Konnarock Formation - Maroon diamictite, rhythmite, and arkose.

Lithology: sedimentary breccia; arkose

Charnockite Gneiss (Proterozoic Y) at surface, covers 0.2 % of this area

Charnockite gneiss

Lithology: gneiss

Dalecarlia Instrusive Suite (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Dalecarlia Instrusive Suite - Monzogranite and granodiorite.

Lithology: monzonite; granodiorite

Erwin and Hampton Formations (Cambrian) at surface, covers 0.5 % of this area

Erwin and Hampton Formations - Sandstone, quartzite, and shale.

Lithology: sandstone; quartzite; shale

Ashe Formation - Biotite gneiss (Proterozoic Z) at surface, covers 2 % of this area

Ashe Formation - Biotite gneiss.

Lithology: biotite gneiss

Metagraywacke, Quartzose Schist, and Melange (Proterozoic Z-Cambrian) at surface, covers 2 % of this area

Metagraywacke, Quartzose Schist, and Melange - Meta-argillite is metagraywacke; quartzose schist

Lithology: meta-argillite; schist; melange

McKenzie Formation and Clinton Group (Silurian) at surface, covers < 0.1 % of this area

McKenzie Formation and Clinton Group - includes the McKenzie Formation, consisting of shale with thin limestone lenses; the dark Rochester Shale; the white Keefer Sandstone; and the Rose Hill predominantly red shale, with thin sandstone interbeds, some of which are called "iron sandstones" from their reddish-brown color and hematite content.

Lithology: shale; sandstone; limestone

Beekmantown Group (Ordovician) at surface, covers 2 % of this area

Beekmantown Group - Dolomite, limestone, and chert. Includes Pinesburg Station Dolomite, Rockdale Run Formation, Beekmantown Formation, Stonehenge Limestone, and Chepultepec Formation.

Lithology: dolostone (dolomite); limestone; chert

Mather Gorge Formation - Metagraywacke (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Mather Gorge Formation - Metargillite is metagraywacke

Lithology: meta-argillite

Newark Supergroup; Triassic Sandstone, Siltstone, and Shale (Upper Triassic) at surface, covers 1.0 % of this area

Interbedded sandstone, siltstone, and shale

Lithology: sandstone; siltstone; shale

Porphyoblastic Biotite-Plagioclase Augen Gneiss (Proterozoic Y) at surface, covers 1 % of this area

Porphyoblastic biotite-plagioclase augen gneiss

Lithology: augen gneiss

Lower Devonian, Silurian and Upper Ordovician Formations Undivided (Ordovician-Devonian) at surface, covers < 0.1 % of this area

Lower Devonian, Silurian and Upper Ordovician Formations Undivided - Some landslides with intact stratigraphic units in Giles County. Includes: Skrt, Sm, Oun, Ous, Ou, Om. (Shrc, Okpl?)

Lithology: sandstone; shale; siltstone; limestone; mudstone; quartzite; arenite

Chesapeake Group (Tertiary) at surface, covers 3 % of this area

Chesapeake Group - Fine- to coarse-grained sand, silt, clay; variably shelly and diatomaceous

Lithology: sand; silt; clay or mud

Alluvium (Quaternary) at surface, covers 1 % of this area

Alluvium - Poorly sorted organic material, clay, sand, and rounded pebbles and cobbles

Lithology: alluvium; clay or mud; sand

Rich Acres Formation (Cambrian) at surface, covers 0.2 % of this area

Rich Acres Formation - Norite, metagabbro, and diorite.

Lithology: norite; gabbro; diorite

Keefer, Rose Hill, and Tuscarora Formations (Silurian) at surface, covers 0.9 % of this area

Keefer, Rose Hill, and Tuscarora Formations - Quartzarenite, dusky-red shale, and sandstone, Some landslides with intact stratigraphic units in Craig County area..

Lithology: arenite; shale; sandstone

Knox Group (Cambrian-Ordovician) at surface, covers 1 % of this area

Knox Group - dolostone, limestone, sandstone. Includes the Mascot Dolomite, Kingsport Dolomite, Chepultepec Dolomite, Copper Ridge Dolomite. (Includes: Ob, Omk, Occo, Cco, Occc.)

Lithology: dolostone (dolomite); limestone; chert; sandstone

Foliated Biotite Granite (Proterozoic) at surface, covers < 0.1 % of this area

Foliated biotite granite

Lithology: granite

Quaternary and Tertiary Deposits (Tertiary-Quaternary) at surface, covers 0.3 % of this area

Quaternary and Tertiary Deposits - Tabb through Windsor Formations and alluvial/tidal prism deposits.

Lithology: sand; gravel; silt; clay or mud; peat; alluvium

Ultramafic Rocks (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Ultramafic rocks

Lithology: ultramafic rock; schist

Aaron Slate (Proterozoic Z) at surface, covers < 0.1 % of this area

Aaron Slate - Metaconglomerate.

Lithology: meta-conglomerate

Pocono Formation (Mississippian) at surface, covers 0.2 % of this area

Pocono Formation - Sandstone, conglomeratic sandstone, and shale with carbonaceous partings and impure coal beds.

Lithology: sandstone; shale; coal

Interlayered Mafic and Felsic Metavolcanic Rocks - Quartz-muscovite schist and gneiss. (Cambrian) at surface, covers 0.2 % of this area

Interlayered Mafic and Felsic Metavolcanic Rocks - Quartz-muscovite schist and gneiss.

Lithology: pelitic schist; gneiss

Mafic Igneous Complex Undivided (Proterozoic Z-Cambrian) at surface, covers 0.1 % of this area

Mafic Igneous Complex Undivided - Mafic igneous complex.

Lithology: mafic metavolcanic rock

Joynes Neck Sand (Quaternary) at surface, covers < 0.1 % of this area

Joynes Neck Sand - Fine- to coarse-grained sand coarsening downward to gravel and sand, at altitudes to 26 ft. (top of unit).

Lithology: sand; gravel

Leucocharnockite (Proterozoic Y) at surface, covers < 0.1 % of this area

Leucocharnockite

Lithology: granite

Popes Head Formation - Station Hills Phyllite Member. Phyllite. (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Popes Head Formation - Station Hills Phyllite Member. Phyllite.

Lithology: phyllite

Elbrook Formation (Cambrian) at surface, covers 2 % of this area

Elbrook Formation - Dolomite, shale, and minor limestone.

Lithology: dolostone (dolomite); limestone; shale; siltstone

Porphyritic Granite (Proterozoic) at surface, covers < 0.1 % of this area

Porphyritic granite

Lithology: granite

Biotite Granite (Proterozoic) at surface, covers < 0.1 % of this area

Biotite granite

Lithology: granite

Plagiogranite Tonalite (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Plagiogranite tonalite

Lithology: tonalite

Charles City Formation (Quaternary) at surface, covers 1 % of this area

Charles City Formation - Interbedded sand, silt, clay and minor gravel; at altitudes to 70-80 ft. (top of unit).

Lithology: sand; silt; clay or mud; gravel

Candler Formation - Phyllite and schist (Cambrian) at surface, covers 0.6 % of this area

Candler Formation - Phyllite in central Blue Ridge Anticlinorium; Phyllite, metasiltstone and quartz-mica schist in southwest Blue Ridge Anticlinorium

Lithology: phyllite; schist; metasedimentary rock

Quantico Formation - Slate and porphyroblastic schist (Ordovician) at surface, covers 0.2 % of this area

Quantico Formation - Slate and porphyroblastic schist

Lithology: slate; schist

Alligator Back Formation - Actinolite schist (Proterozoic Z-Cambrian) at surface, covers 0.4 % of this area

Alligator Back Formation - Actinolite schist

Lithology: schist

Buckingham Complex - Quarz diorite. (Proterozoic Z-Pennsylvanian) at surface, covers < 0.1 % of this area

Buckingham Complex - Quarz diorite.

Lithology: quartz diorite

Metagabbro (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Metagabbro

Lithology: amphibolite; amphibolite

Candler Formation - Metasiltstone (Cambrian) at surface, covers < 0.1 % of this area

Candler Formation - Meta-argillite is laminated metasiltstone

Lithology: meta-argillite

Lower Tertiary Deposits (Tertiary) at surface, covers 0.3 % of this area

Lower Tertiary Deposits - Glauconitic quartz sand and clay-silt, shelly in part, minor sandy limestone and limey sand; may include the following formations: Brightseat, Aquia, Marlboro, Nanjemay, and Piney Point (Pamunkey Group); and Old Church.

Lithology: sand; silt; limestone

Newark Supergroup; Sandstone, undifferentiated (Upper Triassic) at surface, covers 0.5 % of this area

Sandstone, undifferentiated

Lithology: sandstone

Layered Biotite Granulite and Gneiss (Proterozoic Y) at surface, covers 0.8 % of this area

Layered biotite granulite and gneiss.

Lithology: gneiss; granulite

Chilhowee Group (Cambrian) at surface, covers 1 % of this area

Chilhowee Group - Appalachian Plateaus and Valley and Ridge: Quartzite, conglomerate, feldspathic sandstone, phyllite, and minor ferruginous sandstone and volcanic rocks. Blue Ridge Anticlinorium: Conglomerate, quartzite, metasiltstone, and phyllite.

Lithology: quartzite; conglomerate; sandstone; phyllite; meta-argillite; volcanic rock (aphanitic)

Biotite Granitic Gneiss (Middle Proterozoic) at surface, covers < 0.1 % of this area

Biotite Granitic Gneiss - unconformity; pinkish gray to light gray, massive to well-foliated, granitic to quartz monzonitic; includes variably mylonitized orthogneiss and paragneiss, interlayered amphibolite, calc-silicate rock, and marble. Includes granites of the Bryson City area, Straight Fork window, and Elk Park Plutonic Suite.

Lithology: granitic gneiss; amphibolite; calc-silicate rock; marble

Conococheague Formation (Cambrian) at surface, covers < 0.1 % of this area

Conococheague Formation - predominantly algal and mechanically deposited limestone, with interbeds of aphanitic limestone and dolomite. Contains siliceous and dolomitic laminations. Resistant sandy Big Spring Station Member near the base.

Lithology: limestone; dolostone (dolomite); orthoquartzite

Tabb Formation; Sedgefield Member (Quaternary) at surface, covers 1 % of this area

Tabb Formation; Sedgefield Member - Pebbly to bouldery, clayey sand and shelly sand, at altitudes to 30 ft. (top of unit).

Lithology: sand

Hardy Creek Limestone through Dot Limestone (Ordovician) at surface, covers 0.2 % of this area

Hardy Creek Limestone through Dot Limestone - Limestone, in part cherty; and calcareous shale. Includes Hardy Creek, Ben Hur, Woodway, Hurricane Bridge, Martin Creek, Rob Camp, Poteet, and Dot Limestones.

Lithology: limestone; shale; chert

Pennington Group (Mississippian) at surface, covers 0.2 % of this area

Pennington Group - Shale, sandstone, dusky-red mudstone, conglomerate, siltstone, and limestone.

Lithology: shale; sandstone; mudstone; conglomerate; siltstone; limestone

Newark Supergroup; Conglomerate, greenstone clasts (Upper Triassic) at surface, covers 0.1 % of this area

Conglomerate, greenstone clasts

Lithology: conglomerate

Granite Gneiss (Proterozoic Y-Pennsylvanian) at surface, covers 0.1 % of this area

Granite gneiss.

Lithology: granitic gneiss

Sykesville Formation (Cambrian) at surface, covers 0.1 % of this area

Sykesville Formation - Metasedimentary melange

Lithology: melange

Brallier Formation (Devonian) at surface, covers 2 % of this area

Brallier Formation - Micaceous shale, siltstone, and sandstone.

Lithology: shale; siltstone; sandstone

Diorite and Quartz Diorite (Proterozoic) at surface, covers < 0.1 % of this area

Diorite and quartz diorite.

Lithology: diorite; quartz diorite

Alligator Back Formation - Banded marble (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Alligator Back Formation - Banded marble

Lithology: marble; gneiss; schist

Alligator Back Formation; Gneiss (Late Proterozoic) at surface, covers < 0.1 % of this area

Gneiss - finely laminated to thin layered; locally contains massive gneiss and micaceous granule conglomerate; includes schist, phyllite, and amphibolite.

Lithology: gneiss; conglomerate; schist; phyllite; amphibolite

Two-Mica Granite (Proterozoic Y) at surface, covers < 0.1 % of this area

Two-mica granite.

Lithology: orthogneiss

Chattanooga Shale and Wildcat Valley Sandstone (Devonian-Mississippian) at surface, covers 0.1 % of this area

Chattanooga Shale and Wildcat Valley Sandstone - Black, fissile shale and siltstone; calcareous sandstone

Lithology: black shale; siltstone; sandstone

Lee Formation (Mississippian to Pennsylvanian ) at surface, covers < 0.1 % of this area

Lee Formation

Lithology: conglomerate; sandstone; siltstone; shale; coal

Layered Pyroxene Granulite (Proterozoic Y) at surface, covers 0.9 % of this area

Layered pyroxene granulite

Lithology: granulite

Old Rag Granite (Proterozoic Y) at surface, covers < 0.1 % of this area

Old Rag granite - Granite

Lithology: granite

Tabb Formation: Lynnhaven and Poquoson Members (Quaternary) at surface, covers 0.6 % of this area

Tabb Formation: Lynnhaven and Poquoson Members - Undifferentiated Qtl, Qts.

Lithology: sand; silt

Greenbrier Limestone (Mississippian) at surface, covers 0.2 % of this area

Greenbrier Limestone - Limestone, in part cherty, fossiliferous; shale.

Lithology: limestone; shale; chert; dolostone (dolomite)

Juniata and Oswego Formations (Ordovician) at surface, covers < 0.1 % of this area

Juniata and Oswego Formations - the Juniata is a thin-bedded, blocky, red sandstone and shale. In places it is underlain by the thick-bedded, gray Oswego Sandstone.

Lithology: sandstone; shale

Metatrondhjemite (Proterozoic Y) at surface, covers < 0.1 % of this area

Metatrondhjemite

Lithology: biotite gneiss

Ta River Metamorphic Suite (Cambrian) at surface, covers 0.3 % of this area

Ta River Metamorphic Suite - Amphibolite gneiss

Lithology: amphibolite; gneiss; schist; quartzite; biotite gneiss; felsic volcanic rock; gabbro; granite

Ashe Formation - Moneta Gneiss (Proterozoic Z) at surface, covers 0.2 % of this area

Ashe Formation - Moneta Gneiss - Hornblende and hornblende-biotite gneiss

Lithology: mafic gneiss

Maccrady Shale and Price Formation (Mississippian) at surface, covers 0.3 % of this area

Maccrady Shale and Price Formation - Includes: Maccrady Shale: Dusky-red and green shale and mudstone; and evaporite deposits. Price Formation: Sandstone, conglomeratic sandstone, and shale with carbonaceous partings and impure coal beds.

Lithology: sandstone; shale; mudstone; coal; evaporite

Ashe Formation -Mica schist or phyllite (Proterozoic Z) at surface, covers 0.1 % of this area

Ashe Formation - Mica schist or phyllite

Lithology: mica schist; phyllite

Arvonia Formation - Porphyroblastic garnet-biotite schist (Ordovician) at surface, covers < 0.1 % of this area

Arvonia Formation - Porphyroblastic garnet-biotite schist

Lithology: mica schist

Red Oak Pluton (Proterozoic) at surface, covers < 0.1 % of this area

Red Oak pluton - Granite

Lithology: granite

Bassett Formation - Biotite gneiss and granite gneiss. (Proterozoic Z) at surface, covers 0.8 % of this area

Bassett Formation - Quartzofeldspathic biotite gneiss and granite gneiss.

Lithology: biotite gneiss; granitic gneiss

Stonehenge Limestone (Ordovician) at surface, covers < 0.1 % of this area

Stonehenge Limestone - gray, thin-bedded to massive, fossiliferous limestone, largely mechanically deposited, with small black chert nodules and beds of "edgewise" conglomerate. The highly resistant Stoufferstown Limestone member is found at the base.

Lithology: limestone; chert; conglomerate

Biotite Granite (Proterozoic Y) at surface, covers < 0.1 % of this area

Biotite granite

Lithology: granite

Newark Supergroup, Dan River Group; Cow Branch Formation (Triassic) at surface, covers < 0.1 % of this area

Cow Branch Formation - mudstone with minor sandstone, gray, laterally-continuous bedding. Intertongues with Stoneville and Pine Hall formations.

Lithology: mudstone; sandstone

Leucocratic Granulite and Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Leucocratic granulite and gneiss.

Lithology: granulite; gneiss

Silurian and Upper Ordovician Formations Undivided (Ordovician-Silurian) at surface, covers < 0.1 % of this area

Silurian and Upper Ordovician Formations Undivided - Includes: Skrt, Sm, Oun, Ous, Ou, Om. (Shrc and Okpl?)

Lithology: sandstone; shale; siltstone; limestone; mudstone; quartzite; arenite

Newark Supergroup; Jurassic Interbedded Sandstone and Siltstone (Lower Jurassic) at surface, covers < 0.1 % of this area

Interbedded sandstone and siltstone

Lithology: sandstone; siltstone

Mount Rogers Formation - Phenocryst-poor rhyolite (Proterozoic Z) at surface, covers < 0.1 % of this area

Mount Rogers Formation - Phenocryst-poor rhyolite

Lithology: rhyolite

Elk Park Plutonic Group - Biotite augen gneiss (Proterozoic Y) at surface, covers 0.1 % of this area

Elk Park Plutonic Group - Biotite augen gneiss and porphyritic gneiss

Lithology: augen gneiss; quartz monzonite

Amphibolite (Cambrian/Late Proterozoic) at surface, covers < 0.1 % of this area

Amphibolite - equigranular, massive to well foliated, dioritic to basaltic dikes and sills; variably metamorphosed.

Lithology: amphibolite; basalt; diorite

Layered Porphyrobliastic Pyroxene Granulite (Proterozoic Y) at surface, covers < 0.1 % of this area

Layered porphyroblastic pyroxene granulite

Lithology: granulite

Mine Run Complex - Melange Zone II (Proterozoic Z-Ordovician) at surface, covers 0.2 % of this area

Mine Run Complex - Melange Zone II

Lithology: melange

Falls Run Granite Gneiss (Silurian) at surface, covers < 0.1 % of this area

Falls Run Granite Gneiss - Granite

Lithology: granite

Oriskany Sandstone and Helderberg Group, undivided (Devonian) at surface, covers < 0.1 % of this area

Oriskany Sandstone and Helderberg Group, undivided - Oriskany Sandstone: sometimes designated Ridgeley in eastern West Virginia. White to brown coarse- to fine-grained, partly calcareous sandstone, locally pebbly or conglomeratic, and ridge-forming. May be white, nearly pure silica, and a source of glass sand, as at Berkeley Springs, Morgan County. Helderburg Group: mostly cherty limestone, with some sandstone and shale. Contains several named stratigraphic units, including the Keyser Formation, which is partly Silurian and includes the Clifton Forge Sandstone and Big Mountain Shale Members.

Lithology: sandstone; limestone; shale

Lower Devonian and Silurian Formations Undivided (Silurian-Devonian) at surface, covers 0.6 % of this area

Lower Devonian and Silurian Formations Undivided - Some landslides with intact stratigraphic units in Craig County area. Includes: Dsu, Skrt, Sm. (Shrc?)

Lithology: sandstone; limestone; shale

Tabb Formation (Quaternary) at surface, covers < 0.1 % of this area

Tabb Formation - Undifferentiated. Includes the Poquoson Member (Qtp), Lynnhaven Member ( Qtl) and Sedgefield Member (Qts).

Lithology: sand; silt; peat

Biotite-Muscovite Granite (Proterozoic) at surface, covers 0.1 % of this area

Biotite-muscovite granite

Lithology: granite

Biotite Granodiorite (Proterozoic) at surface, covers < 0.1 % of this area

Biotite granodiorite

Lithology: granodiorite

Chuckatuck Formation (Quaternary) at surface, covers 0.2 % of this area

Chuckatuck Formation - Interbedded gravel, sand, silt, clay, and minor peat; at altitudes to 50-60 ft. (top of unit).

Lithology: gravel; sand; silt; clay or mud; peat

Buffalo Granite (Proterozoic) at surface, covers 0.3 % of this area

Buffalo granite - Granite

Lithology: granite

Porphyroblastic Biotite Gneiss (Proterozoic) at surface, covers 0.5 % of this area

Porphyroblastic biotite gneiss

Lithology: biotite gneiss

Mather Gorge Formation -- Schist (Proterozoic Z-Cambrian) at surface, covers 0.2 % of this area

Mather Gorge Formation - Schist.

Lithology: schist; gneiss; metasedimentary rock; calc-silicate rock

Tabb Formtaion; Poquoson Member (Quaternary) at surface, covers 0.1 % of this area

Tabb Formtaion; Poquoson Member - Pebbly sand grading upward into muddy, fine-grained sand and sandy silt, at altitudes to 11 ft. (top of unit).

Lithology: sand; silt

Upper and Middle Ordovician Formations Undivided (Ordovician) at surface, covers < 0.1 % of this area

Upper and Middle Ordovician Formations Undivided - Includes: Oun, Ous, Ou, Om, Okpl, Oeln, Oml, Ols.

Lithology: shale; sandstone; mudstone; limestone; siltstone; graywacke; chert

Swift Run Formation (Proterozoic Z) at surface, covers < 0.1 % of this area

Swift Run Formation - Phyllite, metasandstone, and metaconglomerate.

Lithology: phyllite; sandstone; meta-conglomerate; schist; quartzite; slate

Alligator Back Formation - Feldspathic metagraywacke (Proterozoic Z-Cambrian) at surface, covers 2 % of this area

Alligator Back Formation - Meta-argillite is feldspathic metagraywacke; graphitic mica schist, and quartzite.

Lithology: meta-argillite; schist; quartzite; melange; marble; gneiss

Interlayered Mafic and Felsic Metavolcanic Rocks - Foliated felsite (Cambrian) at surface, covers 0.8 % of this area

Interlayered Mafic and Felsic Metavolcanic Rocks - Foliated felsite

Lithology: felsic volcanic rock; schist; gneiss; breccia

Pocono Group (Mississippian) at surface, covers < 0.1 % of this area

Pocono Group - predominantly hard gray massive sandstones, with some shale. In the Eastern Panhandle, has been divided into the Hedges, Purslane, and Rockwell Formations.

Lithology: sandstone; shale

Metasedimentary Rocks Undivided (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Metasedimentary rocks

Lithology: metasedimentary rock; quartzite; schist; phyllite;

Catoctin Formation - Metasedimentary rocks (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Catoctin Formation - Metasedimentary rocks

Lithology: quartzite; sandstone; meta-argillite; phyllite

Martinsburg and Oranda Formations (Ordovician) at surface, covers 1 % of this area

Martinsburg and Oranda Formations - Shale, sandstone, siltstone, and limestone.

Lithology: shale; sandstone; siltstone; limestone

Conasauga Group, including Maynardville Limestone, Nolichucky Shale, the Maryville, Rogersville, and Rutledge Formations, Pumpkin Valley Shale, Rome Formation, and Shady Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Conasauga Group - Mostly shale northwest of a line connecting Etowah and Bearden (Knoxville); to the east it consists of the six formations at right [Cmn, Maynardville Limestone. Ccl including Cn, Nolichucky Shale, Cmr Maryville, Rogersville, and Rutledge Formations, and Pumpkin Valley Shale; Cr, Rome Formation, and Cs, Shady Dolomite. Thickness about 2,000 feet.

Lithology: shale; limestone; dolostone (dolomite); sandstone; siltstone

Shelton Formation (Ordovician) at surface, covers 0.1 % of this area

Shelton Formation - Granite and quartz monzonite gneiss

Lithology: granite; gneiss

Robertson River Igneous Suite - Laurel Mills granite (Proterozoic Z) at surface, covers 0.1 % of this area

Robertson River Igneous Suite - Laurel Mills granite

Lithology: granite

Artificial Fill (Quaternary) at surface, covers < 0.1 % of this area

Artificial Fill - Areas filled for construction and waste disposal

Lithology: unconsolidated deposit

Lynchburg Group; Graphitic phyllite and metasiltstone (Proterozoic Z) at surface, covers < 0.1 % of this area

Lynchburg Group - Graphitic phyllite and metasiltstone

Lithology: phyllite; meta-argillite; slate; metasedimentary rock; quartzite

Layered Quartzofeldspathic Augen Gneiss and Flaser Gneiss (Proterozoic Y) at surface, covers 0.5 % of this area

Layered quartzofeldspathic augen gneiss and flaser gneiss.

Lithology: felsic gneiss; flaser gneiss

Columbia pluton (Ordovician) at surface, covers < 0.1 % of this area

Columbia pluton - Granite

Lithology: granite

Diana Mills Complex (Proterozoic Z-Pennsylvanian) at surface, covers < 0.1 % of this area

Diana Mills Complex - Metamorphosed mafic and ultramafic rocks

Lithology: mafic gneiss; amphibolite

Newark Supergroup; Jurassic Siltstone and Shale (Jurassic) at surface, covers < 0.1 % of this area

Interbedded siltstone and shale

Lithology: shale; siltstone

Amphibolite, Amphibole Gneiss, and Schist (Proterozoic Y) at surface, covers < 0.1 % of this area

Amphibolite, amphibole gneiss, and schist.

Lithology: schist; gneiss; amphibolite

Lynchburg Group; Metagraywacke (Proterozoic Z) at surface, covers 0.4 % of this area

Lynchburg Group - Metagraywacke

Lithology: meta-argillite; schist; conglomerate

Juniata, Reedsville, Trenton, and Eggleston Formations (Ordovician) at surface, covers 0.9 % of this area

Juniata, Reedsville, Trenton, and Eggleston Formations - Dusky-red shale and mudstone and sandstone; shale and limestone. Note: one area in southeastern Bland County has landslides with intact stratigraphic units.

Lithology: shale; mudstone; sandstone; limestone

Leatherwood Granite (Cambrian) at surface, covers 0.2 % of this area

Leatherwood Granite - Granite

Lithology: granite

Altered Diorite and Gabbro (Proterozoic) at surface, covers < 0.1 % of this area

Altered diorite and gabbro

Lithology: diorite; gabbro

Felsic Volcanic and Volcaniclastic Rocks (Proterozoic Z) at surface, covers < 0.1 % of this area

Felsic volcanic and volcaniclastic rocks.

Lithology: felsic volcanic rock; mixed clastic/volcanic

Biotite Granite Gneiss (Proterozoic) at surface, covers 0.2 % of this area

Biotite granite gneiss

Lithology: granitic gneiss

Interlayered Mafic and Felsic Metavolcanic Rocks - Amphibolite, hornblende-biotite gneiss, and schist. (Cambrian) at surface, covers 0.8 % of this area

Interlayered Mafic and Felsic Metavolcanic Rocks - Amphibolite, hornblende-biotite gneiss, and schist.

Lithology: amphibolite; biotite gneiss; schist

Fauquier Formation - Metasiltstone and phyllite (Proterozoic Z) at surface, covers < 0.1 % of this area

Fauquier Formation - Meta-argillite is laminated metasiltstone; and phyllite.

Lithology: meta-argillite; phyllite

Miocene Sand and Gravel (Tertiary) at surface, covers 0.2 % of this area

Miocene Sand and Gravel - Sandy gravel, sand, silt, and clay.

Lithology: gravel; sand; silt; clay or mud

Unicoi Formation (Cambrian) at surface, covers 0.2 % of this area

Unicoi Formation - Sandstone and quartzite with phyllite, tuffaceous phyllite, conglomerate, and minor basalt.

Lithology: sandstone; quartzite; phyllite; conglomerate; basalt

Beach Sand and Dune Sand Deposits (Quaternary) at surface, covers 0.1 % of this area

Beach Sand and Dune Sand Deposits - Fine- to coarse-grained quartz sand, poorly to well-sorted.

Lithology: beach sand; dune sand

Mafic and Felsic Volcanic Rocks (Proterozoic) at surface, covers 0.6 % of this area

Mafic and felsic volcanic rocks

Lithology: metavolcanic rock

Marcellus Shale and Needmore Formation (Devonian) at surface, covers 0.1 % of this area

Marcellus Shale and Needmore Formation - Black, fissile shale; gray, non-fissile shale; Tioga metabentonite at top of Needmore

Lithology: black shale; shale; bentonite; limestone

Waynesboro Formation (Cambrian) at surface, covers 0.3 % of this area

Waynesboro Formation - Dolomite, dusky-red and green shale, limestone, and sandstone.

Lithology: dolostone (dolomite); shale; limestone; sandstone

Moccasin or Bays Formation through Blackford Formation (Ordovician) at surface, covers 1 % of this area

Moccasin or Bays Formation through Blackford Formation - Dusky-red shale and mudstone; sandstone; limestone, in part cherty; and calcareous shale.

Lithology: shale; mudstone; sandstone; limestone; chert

Hampshire Formation (Devonian) at surface, covers 0.6 % of this area

Hampshire Formation - Dusky-red to grayish-red shale, mudrock, and sandstone.

Lithology: sandstone; limestone; shale

State Farm Gneiss (Proterozoic Y) at surface, covers 0.2 % of this area

State Farm Gneiss - Hornblende-biotite granite gneiss

Lithology: gneiss

Ashe Formation- Amphibolite (Proterozoic Z) at surface, covers 0.2 % of this area

Ashe Formation - Amphibolite and garnet amphibolite

Lithology: amphibolite

Tabb Formation; Lynnhaven Member (Quaternary) at surface, covers 1 % of this area

Tabb Formation; Lynnhaven Member - Pebbly and cobbly sand grading upward into muddy, fine sand and silt, at altitudes to 15-18 ft. (top of unit).

Lithology: sand; silt

Pliocene Sand and Gravel (Tertiary) at surface, covers 2 % of this area

Pliocene Sand and Gravel - Sandy gravel, gravelly sand, poorly to well-sorted sands, and thin- to medium-beds of clay and silt, at altitudes from 170-320 ft. (top of unit).

Lithology: gravel; sand; clay or mud; silt

Fauquier Formation - Arkosic metasandstone (Proterozoic Z) at surface, covers 0.1 % of this area

Fauquier Formation - Arkosic metasandstone

Lithology: metasedimentary rock

Terrace Deposits (Tertiary) at surface, covers 0.2 % of this area

Terrace Deposits - Poorly sorted clay, sand, and rounded pebbles and cobbles, deeply weathered

Lithology: terrace; clay or mud; sand; gravel

Metavolcanic and Metasedimentary Rocks - Greenstone or amphibole gneiss. (Cambrian) at surface, covers 0.2 % of this area

Metavolcanic and Metasedimentary Rocks - Greenstone or amphibole gneiss.

Lithology: greenstone; gneiss

Flint Hill Gneiss (Proterozoic Y) at surface, covers 0.2 % of this area

Flint Hill Gneiss - Gneiss.

Lithology: gneiss

Moorings Unit of Oaks and Coch (1973) (Tertiary) at surface, covers 0.3 % of this area

Moorings Unit of Oaks and Coch (1973) - Sand, silt, and clay; at altitudes from 100-130 ft. (top of unit).

Lithology: sand; silt; clay or mud

Waynesboro Formation and Tomstown Dolomite (Cambrian) at surface, covers 0.1 % of this area

Waynesboro Formation and Tomstown Dolomite - Waynesboro Formation: Dolomite, dusky-red and green shale, limestone, and sandstone. Tomstown Dolomite: Dolomite, in part cherty.

Lithology: dolostone (dolomite); shale; limestone; sandstone; chert

Price Formation (Mississippian) at surface, covers 0.2 % of this area

Price Formation - Sandstone, conglomeratic sandstone, and shale with carbonaceous partings and impure coal beds.

Lithology: sandstone; shale; siltstone; limestone; conglomerate; coal

Burkeville Pluton (Proterozoic) at surface, covers 0.2 % of this area

Burkeville pluton - Granodiorite and monzonite.

Lithology: granodiorite; monzonite

Edinburg Formation, Lincolnshire and New Market Limestones (Ordovician) at surface, covers 0.7 % of this area

Edinburg Formation, Lincolnshire and New Market Limestones - Black limestone and shale; gray limestone, in part cherty

Lithology: limestone; black shale; chert

Conasauga Shale (Cambrian) at surface, covers < 0.1 % of this area

Conasauga Shale - Shale with minor limestone and sandstone.

Lithology: shale; limestone; sandstone

Petersburg Granite (Mississippian) at surface, covers 0.8 % of this area

Petersburg Granite - Granite

Lithology: granite

Chemung Group (Devonian) at surface, covers < 0.1 % of this area

Chemung Group - gray to brown siltstone and sandstone with shale and conglomeratic interbeds; mainly marine and sparingly fossiliferous; boundaries gradational. Can be divided into the Voreknobs and Scherr Formations along the Allegheny Front. Parkhead Sandstone Member near base.

Lithology: siltstone; sandstone; shale; conglomerate

Juniata, Oswego, Martinsburg (Reedsville and Dolly Ridge), and Eggleston Formations (Ordovician) at surface, covers 0.6 % of this area

Juniata, Oswego, Martinsburg (Reedsville and Dolly Ridge), and Eggleston Formations - Dusky-red shale and mudstone and sandstone; graywacke; shale and sandstone; and limestone.

Lithology: shale; mudstone; sandstone; graywacke; limestone

Layered Leucocratic Granite Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Layered leucocratic granite gneiss

Lithology: granitic gneiss

Alkali Feldspar Leucogranite (Proterozoic Y) at surface, covers < 0.1 % of this area

Alkali feldspar leucogranite

Lithology: granite

Nolichucky and Honaker Formations (Cambrian) at surface, covers 0.6 % of this area

Nolichucky and Honaker Formations - Dolomitic shale; dolomite and minor chert.

Lithology: shale; dolostone (dolomite); chert

Millboro Shale and Needmore Formation (Devonian) at surface, covers 1 % of this area

Millboro Shale and Needmore Formation - Black, fissile shale; gray calcareous shale; Tioga metabentonite at top of Needmore.

Lithology: black shale; shale; bentonite; limestone

Porphyritic Leucocharnockite (Proterozoic Y) at surface, covers 0.1 % of this area

Porphyritic Leucocharnockite - Leucocharnockite

Lithology: granite

Kent Island Formation (Quaternary) at surface, covers 0.3 % of this area

Kent Island Formation - Medium- to coarse-grained sand and sandy gravel grading upward into poorly- to well-sorted fine- to medium-grained sand, in part clayey and silty, at altitudes from sea level to about 20 ft. (top of unit).

Lithology: sand; gravel

Ridgeley Sandstone, Helderberg and Cayugan Groups (Silurian-Devonian) at surface, covers 1 % of this area

Ridgeley Sandstone, Helderberg and Cayugan Groups - Calcareous sandstone; partly cherty limestone; calcareous shale; fossiliferous.

Lithology: limestone; sandstone; shale

Silurian Formations Undivided (Silurian) at surface, covers 0.5 % of this area

Silurian Formations Undivided - Some landslides with intact stratigraphic units in Giles County area. Includes: Dsu, Skrt, Sm. (Shrc?)

Lithology: sandstone; shale; limestone; arenite; conglomerate

Knobs Formation, Paperville Shale, Lenoir and Mosheim Limestone (Ordovician) at surface, covers 0.2 % of this area

Knobs Formation, Paperville Shale, Lenoir and Mosheim Limestone - Sandstone, conglomerate, siltstone; black, fissile shale; and limestone, in part cherty.

Lithology: sandstone; conglomerate; siltstone; black shale; limestone; chert

Nolichucky Shale, and Maryville, Rogersville, and Rutledge Formations, and Pumpkin Valley Shale (Cambrian) at surface, covers < 0.1 % of this area

(Cn) Nolichucky Shale - Pastel-colored (pink, greenish, olive), flaky clay shale; gray, commonly oolitic, shaly limestone lenses; locally stromatolitic limestone layers; thin, blocky siltstone near middle. Thickness 500 feet in the east to 900 feet in the west.; (Cmr) Maryville, Rogersville, and Rutledge Formations - Maryvile and Rutledge are gray limestone, in part oolitic, with gray dolomite locally. Rogersville is green clay shale. Thickness 400 to 1,000 feet. Pumpkin Valley Shale - Dull-brown to maroon shale with numerous interbeds of thin, blocky, sandy siltstone. Thickness 100 to 600 feet.

Lithology: shale; limestone; dolostone (dolomite); siltstone

Lahore Complex - Amphibole monzonite (Ordovician) at surface, covers < 0.1 % of this area

Lahore Complex - Amphibole monzonite

Lithology: monzonite

Plagiogranite (Proterozoic) at surface, covers < 0.1 % of this area

Plagiogranite

Lithology: granitoid

Hornblende-plagioclase Gabbro (Proterozoic) at surface, covers 0.1 % of this area

Hornblende Gabbro in Carolina Slate Belt; Hornblende-Plagioclase Gabbro in Central Virginia Volcanic-Plutonic Belt; Gabbro, Hornblendite and Norite in Central Piedmont

Lithology: gabbro; norite

Wise Formation (Pennsylvanian) at surface, covers 0.8 % of this area

Wise Formation - Sandstone, shale, siltstone, and coal; quartzarenite.

Lithology: sandstone; siltstone; shale; coal

Rome Formation (Cambrian) at surface, covers 1 % of this area

Rome Formation - Dusky-red and green shale and siltstone, dolomite, and limestone.

Lithology: shale; siltstone; sandstone; dolostone (dolomite); limestone

Lahore Complex - Mafic and ultramafic rocks (Ordovician) at surface, covers < 0.1 % of this area

Lahore Complex - Mafic and ultramafic rocks

Lithology: metamorphic rock; pyroxenite

Actinolite Schist Metabasalt (Proterozoic) at surface, covers < 0.1 % of this area

Actinolite schist metabasalt

Lithology: meta-basalt

Arvonia Formation - Bremo quartzite. Quartzite (Ordovician) at surface, covers < 0.1 % of this area

Arvonia Formation - Bremo quartzite. Quartzite

Lithology: quartzite

Bassett Formation - Amphibolite. (Proterozoic Z-Cambrian) at surface, covers 0.2 % of this area

Bassett Formation - Amphibolite.

Lithology: amphibolite; gneiss; schist

Falls Church Intrusive Suite (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Falls Church Intrusive Suite - Tonalite, granodiorite, monzogranite, and trondhjemite.

Lithology: tonalite; granodiorite; granite; trondhjemite

Ashe Metamorphic Suite and Tallulah Falls Formation; Amphibolite (Late Proterozoic) at surface, covers < 0.1 % of this area

Amphibolite - equigranular, massive to well foliated, interlayered, rarely discordant, metamorphosed intrusive to extrusive mafic rock; may include metasedimentary rock.

Lithology: amphibolite; metasedimentary rock

Elbrook Formation (Cambrian) at surface, covers < 0.1 % of this area

Elbrook Formation - thin-bedded blue-gray argillaceous limestone and platy shale, with some siliceous limestone and minor dolomite.

Lithology: limestone; shale; dolostone (dolomite)

Tuscarora Sandstone (Silurian) at surface, covers < 0.1 % of this area

Tuscarora Sandstone - medium- to thick-bedded, white to gray or pinkish sandstone, fine to coarse, quartzitic, ridge-forming. Equivalent to the Clinch Sandstone of Tennessee.

Lithology: sandstone

Mount Rogers Formation - Conglomerate, graywacke, laminated siltstone, and shale. (Proterozoic Z) at surface, covers < 0.1 % of this area

Mount Rogers Formation - Conglomerate, graywacke, laminated siltstone, and shale.

Lithology: conglomerate; graywacke; siltstone; shale; greenstone; rhyolite

Candler Formation - Lmestone (Cambrian) at surface, covers < 0.1 % of this area

Candler Formation - Limestone.

Lithology: limestone; mudstone

Norton Formation (Pennsylvanian) at surface, covers 2 % of this area

Norton Formation - Shale, siltstone, sandstone, and coal.

Lithology: shale; siltstone; sandstone; coal

Lake Jackson Pluton (Ordovician) at surface, covers < 0.1 % of this area

Lake Jackson Pluton - Micaceous metatonalite.

Lithology: felsic gneiss

Interlayered Mafic and Felsic Volcanic Rocks (Proterozoic Z) at surface, covers 0.4 % of this area

Interlayered mafic and felsic metavolcanic rocks.

Lithology: mafic metavolcanic rock; felsic metavolcanic rock; metasedimentary rock

Mount Rogers Formation - Porphyritic rhyolite (Proterozoic Z) at surface, covers < 0.1 % of this area

Mount Rogers Formation - Porphyritic rhyolite

Lithology: rhyolite

Biotite Gneiss (Proterozoic) at surface, covers 1 % of this area

Biotite gneiss

Lithology: biotite gneiss

Marcellus Formation and Needmore Shale, undivided (Devonian) at surface, covers < 0.1 % of this area

Marcellus Formation and Needmore Shale, undivided - Marcellus Formation (part of Millboro Shale): predominantly gray-black to black thinly laminated non-calcareous pyritic shale. Contains one or more thin-bedded limestones, including the Purcell Member of Pennsylvania. Needmore Shale (part of Onesquethaw ("Onondaga") Group): predominantly dark grey or green, calcitic, mostly non-fissile shale. Gives strong "kick" on gamma ray logs. Tioga Bentonite near the top. Includes the black Beaver Dam Shale Member. Grades westward into the Huntersville Chert. Not mappable at scale of this map. Included with Dmn.

Lithology: shale; black shale; limestone; bentonite

Fauquier Formation -Meta-arkose and metasiltstone (Proterozoic Z) at surface, covers < 0.1 % of this area

Fauquier Formation - Crossbedded metasandstone

Lithology: metasedimentary rock

Green Springs Pluton - Diorite and hornblendite. (Proterozoic Y-Pennsylvanian) at surface, covers < 0.1 % of this area

Green Springs Pluton - Diorite and hornblendite.

Lithology: diorite; hornblendite

Metavolcanic and Metavolcanic Clastic Phyllite (Proterozoic - Cambrian) at surface, covers < 0.1 % of this area

Metavolcanic and metavolcanic clastic phyllite

Lithology: phyllite

Lee Formation (Pennsylvanian) at surface, covers 0.3 % of this area

Lee Formation - Quartzarenite, sandstone, conglomerate, shale, siltstone, and coal.

Lithology: arenite; sandstone; conglomerate; shale; siltstone; coal

Mafic Plutonic Rocks (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Mafic plutonic rocks as exotic blocks within melange units

Lithology: mafic rock

Melrose Granite (Cambrian) at surface, covers < 0.1 % of this area

Melrose Granite - Granite

Lithology: granite; quartz monzonite; quartz diorite

McKenzie Formation, Clinton Group and Tuscarora Sandstone, undivided (Silurian) at surface, covers < 0.1 % of this area

McKenzie Formation, Clinton Group and Tuscarora Sandstone, undivided - McKenzie Formation and Clinton Group: includes the McKenzie Formation, consisting of shale with thin limestone lenses; the dark Rochester Shale; the white Keefer Sandstone; and the Rose Hill predominantly red shale, with thin sandstone interbeds, some of which are called "iron sandstones" from their reddish-brown color and hematite content. Tuscarora Sandstone: medium- to thick-bedded, white to gray or pinkish sandstone, fine to coarse, quartzitic, ridge-forming. Equivalent to the Clinch Sandstone of Tennessee.

Lithology: shale; sandstone; limestone

Robertson River Igneous Suite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - White Oak alkali feldspar granite

Lithology: granite

Metasandstone and Metasiltstone (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Metasandstone and metasiltstone.

Lithology: metasedimentary rock; meta-argillite

Helderberg Group (Devonian) at surface, covers < 0.1 % of this area

Helderberg Group - mostly cherty limestone, with some sandstone and shale. Contains several named stratigraphic units, including the Keyser Formation, which is partly Silurian and includes the Clifton Forge Sandstone and Big Mountain Shale Members.

Lithology: limestone; sandstone; shale

Valley and Ridge Igneous Intrusions; Peridotite (Jurassic-Tertiary) at surface, covers < 0.1 % of this area

Valley and Ridge Igneous Intrusions; p: Peridotite - Dikes in Augusta and Rockingham Counties: nepheline syenite, teschenite-syenite, and teschenite-picrite. Igneous bodies in Highland County: andesite and basalt.

Lithology: peridotite; syenite

Ultramafic Rocks (Proterozoic) at surface, covers < 0.1 % of this area

Ultramafic rocks

Lithology: ultramafitite (komatiite)

Lower Ordovician and Upper Cambrian Formations Undivided (Cambrian-Ordovician) at surface, covers 0.2 % of this area

Lower Ordovician and Upper Cambrian Formations Undivided - Includes Pinesburg Station Dolomite, Rockdale Run Formation, Beekmantown Formation, Stonehenge Limestone and Conococheague Formation.

Lithology: limestone; dolostone (dolomite); chert; sandstone

Biotite Granodiorite and Biotite Granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Biotite granodiorite, biotite granite

Lithology: granodiorite; granite

Wise Formation and Gladeville Sandstone (Pennsylvanian) at surface, covers < 0.1 % of this area

Wise Formation and Gladeville Sandstone - Sandstone, shale, siltstone, and coal; quartzarenite.

Lithology: sandstone; siltstone; shale; coal; arenite

Carysbrook Pluton (Proterozoic) at surface, covers 0.1 % of this area

Carysbrook pluton - Granite.

Lithology: granite

Biotite Granite (Proterozoic) at surface, covers 0.2 % of this area

Biotite granite

Lithology: granite

Nassawadox Formation: Occohannock Member (Quaternary) at surface, covers 0.2 % of this area

Nassawadox Formation: Occohannock Member - Muddy fine- to medium-grained sand, at altitudes to 30 ft. (top of unit).

Lithology: sand

Catoctin Formation -Metabasalt breccia (low titanium) (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Catoctin Formation - Metabasalt breccia (low titanium)

Lithology: meta-basalt

Pegmatite - Amelia pegmatite district. (Permian) at surface, covers < 0.1 % of this area

Pegmatite - Amelia pegmatite district.

Lithology: pegmatite

Everona Limestone (Cambrian) at surface, covers < 0.1 % of this area

Everona Limestone - Limestone.

Lithology: limestone; phyllite; slate

Megacrystic Charnockite (Proterozoic Y) at surface, covers < 0.1 % of this area

Megacrystic charnockite

Lithology: granite

Diabase (Jurassic) at surface, covers 0.4 % of this area

Diabase

Lithology: diabase

Felsic Volcanic Rocks (Proterozoic Z) at surface, covers 0.2 % of this area

Felsic volcanic rocks.

Lithology: felsic volcanic rock

Mahantango Formation (Devonian) at surface, covers 0.2 % of this area

Mahantango Formation - Sandstone with interbedded shale, fossiliferous

Lithology: sandstone; siltstone; shale

Newark Supergroup; Conglomerate, arkosic maatrix (Upper Triassic) at surface, covers < 0.1 % of this area

Conglomerate, arkosic matrix

Lithology: conglomerate; arkose

Shady Dolomite (Cambrian) at surface, covers 0.5 % of this area

Shady Dolomite - Dolomite.

Lithology: dolostone (dolomite); limestone; shale

Millboro Shale, Huntersville Chert, and Rocky Gap Sandstone (Devonian) at surface, covers 0.3 % of this area

Millboro Shale, Huntersville Chert, and Rocky Gap Sandstone - Black, fissile shale; chert; and calcareous sandstone

Lithology: black shale; chert; sandstone

Ashe Formation (Proterozoic Z) at surface, covers 0.1 % of this area

Ashe Formation - Biotite gneiss and garnetiferous amphibolite.

Lithology: biotite gneiss; amphibolite; quartzite

Lynchburg Group; Monumental Mills Formation (Proterozoic Z) at surface, covers < 0.1 % of this area

Lynchburg Group; Monumental Mills Formation - Metasandstone, laminated metasiltstone, and mudstone.

Lithology: metasedimentary rock; meta-argillite; mudstone

Massanutten Sandstone (Silurian) at surface, covers 0.1 % of this area

Massanutten Sandstone - Quartzarenite with lenses of conglomerate.

Lithology: arenite; quartzite; conglomerate

Robertson River Igneous Suite - Amissville alkali feldspar granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Amissville alkali feldspar granite

Lithology: granite

Mount Rogers Formation - Porphyritic felsite (Proterozoic Z) at surface, covers < 0.1 % of this area

Mount Rogers Formation - Porphyritic extrusive felsite

Lithology: felsic volcanic rock

Crozet Granite (Proterozoic Y) at surface, covers < 0.1 % of this area

Crozet granite - Granite

Lithology: granite

Alligator Back Formation (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Alligator Back Formation - Garnet-mica schist, garnet amphibolite, hornblende granite gneiss

Lithology: mica schist; amphibolite; gneiss; quartzite

Robertson River Igneous Suite - Arrington Mountain alkali feldspar granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Arrington Mountain alkali feldspar granite

Lithology: granite

Arvonia Formation - Kyanite quartzite and schist. (Ordovician) at surface, covers < 0.1 % of this area

Arvonia Formation - Kyanite quartzite and schist.

Lithology: quartzite; schist

Metagraywacke (Proterozoic) at surface, covers < 0.1 % of this area

Metagraywacke - Meta-argillite is metagraywacke, exotic blocks within melange units

Lithology: meta-argillite

Lineated Biotite Granite Gneiss (Proterozoic) at surface, covers 0.2 % of this area

Lineated biotite granite gneiss

Lithology: granitic gneiss

Wissahickon Formation; Boulder Gneiss (Late Precambrian (?)) at surface, covers < 0.1 % of this area

Wissahickon Formation; Boulder Gneiss - (Formerly mapped as Sykesville and Laurel Formations.) Thick-bedded to massive, pebble- and boulder-bearing, arenaceous to pelitic metamorphic rock; typically a medium-grained, garnet-oligoclase-mica-quartz gneiss; locally an intensely foliated gneiss or schist; apparent thickness 15,000 feet.

Lithology: gneiss; schist

New River Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

New River Formation (part of Pottsville Group) - predominantly sandstone, with some shale, siltstone, and coal. Grades to nearly all sandstone in the subsurface. Extends from the top of the Upper Nuttall Sandstone to the top of the Flattop Mountain Sandstone. Includes the Iaeger, Sewell, Welch, Raleigh, Beckley, Fire Creek, and Pocahontas Nos. 8 and 9 coals.

Lithology: sandstone; shale; siltstone; coal

Catoctin Formation - Hyaloclastite pillow breccia (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Catoctin Formation - Hyaloclastite pillow breccia

Lithology: meta-basalt

Aaron Slate (Proterozoic Z) at surface, covers 0.4 % of this area

Aaron Slate - Phyllite and slate.

Lithology: phyllite; slate; metasedimentary rock

Pegmatite - Goochland pegmatite district. (Proterozoic) at surface, covers < 0.1 % of this area

Pegmatite - Goochland pegmatite district.

Lithology: pegmatite

Hancock, Rose Hill, and Clinch Formations (Silurian) at surface, covers 0.2 % of this area

Hancock, Rose Hill, and Clinch Formations - Limestone and dolomite; dusky-red and green shale and sandstone; and sandstone, shale and conglomerate.

Lithology: shale; siltstone; sandstone; dolostone (dolomite); limestone; conglomerate

Greenbrier Group (Mississippian) at surface, covers < 0.1 % of this area

Greenbrier Group - marine limestone and marine and non-marine red and gray shale, and minor sandstone beds in numerous formational units.

Lithology: limestone; shale; sandstone

Roseland Anorthosite (Proterozoic Y) at surface, covers < 0.1 % of this area

Roseland anorthosite - Anorthosite

Lithology: anorthosite

Nassawadox Formation: Butlers Bluff Member (Quaternary) at surface, covers 0.2 % of this area

Nassawadox Formation: Butlers Bluff Member - Fine- to coarse-grained pebbly sand and sandy gravel, at altitudes to 40 ft. (top of unit).

Lithology: sand; gravel

Bacons Castle Formation (Tertiary) at surface, covers 1 % of this area

Bacons Castle Formation - Poorly sorted sand and laminated sand; clay and silt.

Lithology: sand; clay or mud; silt

Goldvein Pluton (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Goldvein Pluton - Metamonzogranite.

Lithology: granitic gneiss

Amphibole Metagabbro (Cambrian) at surface, covers < 0.1 % of this area

Amphibole Metagabbro

Lithology: amphibolite; gabbro

Amphibolite and Amphibole-Bearing Gneiss and Schist (Proterozoic) at surface, covers < 0.1 % of this area

Amphibolite and amphibole-bearing gneiss and schist.

Lithology: amphibolite; gneiss; schist

Gneissic Granite and Granodiorite (Proterozoic) at surface, covers 0.4 % of this area

Gneissic granite and granodiorite

Lithology: granite; granodiorite

Mahantango Formation (Devonian) at surface, covers < 0.1 % of this area

Mahantango Formation (part of Millboro Shale) - thickly laminated marine shale, siltstone, very fine sandstone, and some limestone, with an occasional coral reef or biostrome. Contains the Clearville and Chaneysville Siltstone Members of Pennsylvania.

Lithology: shale; sandstone; siltstone; limestone; coral

Mine Run Complex - Melange Zone III (Proterozoic Z-Ordovician) at surface, covers 0.5 % of this area

Mine Run Complex - Melange Zone III

Lithology: melange

Chepultepec and Copper Ridge Formations (Cambrian-Ordovician) at surface, covers 0.2 % of this area

Chepultepec and Copper Ridge Formations - Dolomite, minor limestone, chert, and calcareous sandstone.

Lithology: dolostone (dolomite); limestone; chert; sandstone

Phyllite (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Phyllite.

Lithology: phyllite

Robertson River Igneous Suite - Hitt Mountain alkali feldspar syenite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Hitt Mountain alkali feldspar syenite

Lithology: alkali syenite

Lynchburg Group; Quartzite (Proterozoic Z) at surface, covers < 0.1 % of this area

Lynchburg Group - Quartzite

Lithology: quartzite

Mississippian Formations Undivided (Mississippian) at surface, covers 0.2 % of this area

Mississippian Formations Undivided - Includes Pennington Group, Bluefield Formation, Greenbrier Limestone, Maccrady Shale and Price Formation; Includes Newman Limestone, Fort Payne Chert, and Grainger Formation in western Lee County

Lithology: shale; limestone; sandstone; siltstone; dolostone (dolomite); conglomerate; mudstone; arenite; coal; evaporite; chert

Tonoloway, Wills Creek, and Williamsport Formations (Silurian) at surface, covers < 0.1 % of this area

Tonoloway, Wills Creek, and Williamsport Formations - includes the thin-bedded platy argillaceous limestones of the Tonoloway, the thin-bedded shale with fossiliferous limestones of the Wills Creek, the Bloomsburg red clastic facies, and the greenish-brown to white Williamsport Sandstone. The Wills Creek contains anhydrite and rock salt, the latter supplying brine from deep wells along the Ohio River.

Lithology: limestone; shale; sandstone; clastic; chemical

Micaceous Quartzite (Cambrian) at surface, covers < 0.1 % of this area

Micaceous quartzite

Lithology: quartzite; metasedimentary rock; phyllite

Ordovician, middle calcareous units (Ordovician) at surface, covers < 0.1 % of this area

Ordovician - middle calcareous units.

Lithology: limestone

Maynardville Limestone (Cambrian) at surface, covers < 0.1 % of this area

Maynardville Limestone - Thick-bedded, bluish-gray, ribboned (silt and dolomite), nodular limestone; light-gray, fine- grained, laminated to thin-bedded, noncherty dolomite in upper part. Thickness 150 to 400 feet.

Lithology: limestone; dolostone (dolomite)

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

Biotite gneiss and schist.

Lithology: gneiss; schist

Kanawha Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Kanawha Formation - Sandstone, siltstone, shale, and coal.

Lithology: sandstone; siltstone; shale; coal

Biotite Granite Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Biotite granite gneiss

Lithology: granitic gneiss

Mobley Mountain Granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Mobley Mountain granite - Granite

Lithology: granite

Bluefield Formation (Mississippian) at surface, covers < 0.1 % of this area

Bluefield Formation - Calcareous shale and limestone.

Lithology: shale; limestone; siltstone; sandstone; coal; black shale

Quantico Formation - Micaceous quartzite (Ordovician) at surface, covers < 0.1 % of this area

Quantico Formation - Micaceous quartzite

Lithology: quartzite; schist

Chopawamsic Formation - Interlayered felsic and mafic metavolcanic rocks (Cambrian) at surface, covers 0.6 % of this area

Chopawamsic Formation- Interlayered felsic and mafic metavolcanic rocks

Lithology: metavolcanic rock

Harlan Sandstone (Pennsylvanian) at surface, covers < 0.1 % of this area

Harlan Sandstone - Sandstone, siltstone, shale, and coal.

Lithology: sandstone; siltstone; shale; coal

Wachapreague Formation (Quaternary) at surface, covers < 0.1 % of this area

Wachapreague Formation - Coarsening-upward sequence from lower muddy fine-grained sand to upper medium- to coarse-grained gravelly sand, at altitudes from sea level to about 15 ft. (top of unit).

Lithology: sand

Newark Supergroup, Dan River Group; Stoneville Formation (Triassic) at surface, covers < 0.1 % of this area

Stoneville Formation - conglomerate, sandstone, and mudstone, lenticular and laterally-gradational bedding.

Lithology: conglomerate; sandstone; mudstone

Pinesburg Station Dolomite (Ordovician) at surface, covers < 0.1 % of this area

Pinesburg Station Dolomite - fine- to medium-crystalline, brown to light gray dolomite, containing nodular chert.

Lithology: dolostone (dolomite); chert

Abbeyville Gabbro (Proterozoic) at surface, covers < 0.1 % of this area

Abbeyville gabbro

Lithology: gabbro

Ellisville Biotite Granodiorite (Ordovician-Silurian) at surface, covers 0.2 % of this area

Ellisville Biotite Granodiorite - Biotite granodiorite

Lithology: granodiorite

Felsic/Mafic Volcanic Rocks (Proterozoic) at surface, covers < 0.1 % of this area

Felsic/mafic volcanic rocks as exotic blocks within melange units

Lithology: metavolcanic rock

Newark Supergroup; Jurassic Conglomerate (Lower Jurassic) at surface, covers < 0.1 % of this area

Conglomerate

Lithology: conglomerate

Ashe Metamorphic Suite and Tallulah Falls Formation; Muscovite-biotite gneiss (Late Proterozoic) at surface, covers < 0.1 % of this area

Muscovite-biotite gneiss - locally sulfidic; interlayered and gradational with mica schist, minor amphibolite, and hornblende gneiss.

Lithology: gneiss; mica schist; amphibolite

Mascot and Kingsport Dolomites (Ordovician) at surface, covers 0.1 % of this area

Mascot and Kingsport Dolomites - Dolomite, chert, and minor limestone.

Lithology: dolostone (dolomite); chert; limestone

Breathitt Formation, lower part (Pennsylvanian) at surface, covers < 0.1 % of this area

Breathitt Formation, lower part; lower part which includes Livingston Conglomerate Member of Lee Formation in eastern Rockcastle County

Lithology: shale; siltstone; sandstone; coal; conglomerate

Flat Rock Granite (Proterozoic) at surface, covers < 0.1 % of this area

Flat Rock granite - Granite

Lithology: granite

Sequatchie Formation, Reedsville Shale, Trenton Limestone, Eggleston Formation (Ordovician) at surface, covers 0.1 % of this area

Sequatchie Formation, Reedsville Shale, Trenton Limestone, Eggleston Formation - Shale, siltstone, limestone, and sandstone.

Lithology: shale; siltstone; limestone; sandstone

Norton, New River, Lee and Pocahontas Formations Undivided (Pennsylvanian) at surface, covers < 0.1 % of this area

Norton, New River, Lee and Pocahontas Formations Undivided - Norton Formation: siltstone, shale, sandstone, and coal. New River Formation: Sandstone siltstone, shale, coal. Pocahontas Formation: Sandstone, siltstone, shale, and coal. Lee Formation: Quart

Lithology: sandstone; siltstone; shale; coal; arenite; conglomerate

Mine Run Complex - Melange Zone I (Proterozoic Z-Ordovician) at surface, covers 0.1 % of this area

Mine Run Complex - Melange Zone I

Lithology: melange

Bluefield Formation (Mississippian) at surface, covers < 0.1 % of this area

Bluefield Formation (part of Mauch Chunk Group) - red and green shale and sandstone, with a few thin limestone lenses, such as the Reynolds.

Lithology: shale; sandstone; limestone

Quartzite and Quartz-Sericite Tectonite (Proterozoic Y) at surface, covers < 0.1 % of this area

Quartzite and quartz-sericite tectonite

Lithology: quartzite; tectonite

Virgilina Greenstone (Proterozoic Z) at surface, covers 0.1 % of this area

Virgilina Greenstone - Greenstone metabasalt.

Lithology: greenstone

Granite Pegmatite (Proterozoic) at surface, covers < 0.1 % of this area

Granite pegmatite

Lithology: pegmatite

Robertson River Igneous Suite - Rivanna granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Rivanna granite

Lithology: granite

Robertson River Igneous Suite - Battle Mountain granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Battle Mountain granite

Lithology: granite

Alaskite (Proterozoic) at surface, covers < 0.1 % of this area

Alaskite

Lithology: alkali-granite (alaskite)

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

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

Lithology: mica schist; quartzite; calc-silicate rock; biotite gneiss; amphibolite; phyllite

Lahore Complex - Pyroxene monzonite (Ordovician) at surface, covers < 0.1 % of this area

Lahore Complex - Pyroxene monzonite

Lithology: monzonite

Quartzofeldspathic Gneiss (Proterozoic Y-Pennsylvanian) at surface, covers < 0.1 % of this area

Quartzofeldspathic gneiss

Lithology: felsic gneiss

Nolichucky and Maryville Formations, Rogersville Shale, and Rutledge Formation (Cambrian) at surface, covers 0.1 % of this area

Nolichucky and Maryville Formations, Rogersville Shale, and Rutledge Formation - Calcareous shale, limestone, and dolomite.

Lithology: shale; limestone; dolostone (dolomite); siltstone; sandstone

Porphyroblastic Biotite Granite (Proterozoic) at surface, covers 0.3 % of this area

Porphyroblastic biotite granite

Lithology: granite

Robertson River Igneous Suite; Battle Mountain Alkali Feldspar Granite - felsite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Battle Mountain Alkali Feldspar Granite - felsite

Lithology: felsic volcanic rock

Marble (Proterozoic Z) at surface, covers < 0.1 % of this area

Marble.

Lithology: marble

Dune Sand (Quaternary) at surface, covers < 0.1 % of this area

Dune Sand - Fine- to medium-grained, well-sorted quartz sand

Lithology: dune sand

Oriskany Sandstone and Huntersville Chert (Devonian) at surface, covers < 0.1 % of this area

Oriskany Sandstone and Huntersville Chert - Oriskany Sandstone: sometimes designated Ridgeley in eastern West Virginia. White to brown coarse- to fine-grained, partly calcareous sandstone, locally pebbly or conglomeratic, and ridge-forming. May be white, nearly pure silica, and a source of glass sand, as at Berkeley Springs, Morgan County. Huntersville Chert (part of Onesquethaw ("Onondaga") Group): ranges from a nearly pure slightly calcitic or dolomitic chert to an inter-tonguing of such chert and the Needmore Shale. Grades westward in the subsurface to a limestone, commonly considered as "Onondaga". Contains the "glauconitic" Bobs Ridge Sandstone Member. Not mappable at scale of this map. Included with Do.

Lithology: sandstone; chert; limestone

Buffards Formation (Ordovician) at surface, covers < 0.1 % of this area

Buffards Formation - Micaceous conglomerate, schist, and phyllite.

Lithology: conglomerate; schist; phyllite

Schist (Proterozoic) at surface, covers < 0.1 % of this area

Schist as exotic blocks within melange units

Lithology: schist

Newark Supergroup; Arkosic Sandstone (Upper Triassic) at surface, covers 0.1 % of this area

Arkosic sandstone

Lithology: sandstone

Mount Rogers Formation - Greenstone with interbedded sedimentary rocks (Proterozoic Z) at surface, covers < 0.1 % of this area

Mount Rogers Formation - Greenstone with sedimentary interbeds.

Lithology: greenstone; metasedimentary rock

Valley and Ridge Igneous Intrusions; Basalt (Jurassic-Tertiary) at surface, covers < 0.1 % of this area

Valley and Ridge Igneous Intrusions; b: Basalt - Dikes in Augusta and Rockingham Counties: nepheline syenite, teschenite-syenite, and teschenite-picrite. Igneous bodies in Highland County: andesite and basalt.

Lithology: basalt; andesite

Metagabbro (Proterozoic) at surface, covers < 0.1 % of this area

Metagabbro

Lithology: metamorphic rock

Maccrady Formation and Pocono Group, undivided (Mississippian) at surface, covers < 0.1 % of this area

Maccrady Formation and Pocono Group, undivided - Maccrady Formation: red shale and mudrock, red and green sandstone, and minor limestone. Present only from Pendleton County southward. Contains rock salt and gypsum in southwestern Virginia. Pocono Group: predominantly hard gray massive sandstones, with some shale. In the Eastern Panhandle, has been divided into the Hedges, Purslane, and Rockwell Formations.

Lithology: shale; sandstone; mudstone; limestone; chemical

Mount Rogers Group including Bakersville Gabbro, Beech Granite, Cranberry Granite, and Roan Gneiss (Precambrian) at surface, covers < 0.1 % of this area

Mount Rogers Group - Metavolcanics, typically purplish and reddish; massive lavas and tuffs, altered rhyolites and quartz latites; strongly foliated; interbedded arkose, shale, and conglomerate. Thickness 1,000 to 3,000 feet; Includes Bakersville Gabbro - Metagabbro, dark, porphyritic; contains diorite, basalt, anorthosite, and diabase; occurs as thin to massive dikes and lenticular masses; Beech Granite - Granite, porphyritic, light-gray to reddish; coarse potash feldspar crystals and clustered interstitial mafics (chloritized biotite and hornblende) give spotted appearance; includes Max Patch Granite; Cranberry Granite - Complex of intertonguing rock types including migmatite, granitic gneisses, monzonite, quartz diorite, greenstone, mica and hornblende schists, abundant granitic pegmatite; and Roan Gneiss - Layered hornblende and garnet gneiss and granitic migmatite with zones of mica schist and amphibolite, foliation commonly contorted; contains numerous granitic and gabbroic dikes.

Lithology: granite; gabbro; gneiss; schist; amphibolite; monzonite; diorite; basalt; anorthosite; migmatite

Newark Supergroup; Jurassic Basalt (Lower Jurassic) at surface, covers 0.1 % of this area

basalt

Lithology: basalt

Stuart Creek Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Stuart Creek Gneiss - Biotite augen and flaser gneiss

Lithology: augen gneiss; flaser gneiss

North View Granite (Proterozoic) at surface, covers < 0.1 % of this area

North View Granite

Lithology: granite

Metanorite and Metadiorite (Proterozoic Y) at surface, covers < 0.1 % of this area

Metanorite and Metadiorite - Metanorite and metadiorite

Lithology: norite

Piney Branch Complex (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Piney Branch Complex - Metamorphosed mafic and ultramafic rocks

Lithology: serpentinite; schist; plagiogranite

Porphyroblastic Granite Gneiss (Proterozoic Y) at surface, covers 0.2 % of this area

Porphyroblastic granite gneiss

Lithology: granitic gneiss

Popes Head Formation - Old Mill Branch Metasiltstone Member. Meta-argillite is metasiltstone (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Popes Head Formation -Old Mill Branch Metasiltstone Member. Meta-argillite is metasiltstone

Lithology: meta-argillite

Green Springs Pluton - Quartz diorite and granite. (Proterozoic Z-Pennsylvanian) at surface, covers < 0.1 % of this area

Green Springs Pluton - Quartz diorite and granite.

Lithology: quartz diorite; granite

Newark Supergroup; Breccia, mixed clasts (Upper Triassic) at surface, covers < 0.1 % of this area

Breccia, mixed clasts

Lithology: breccia

Purcell Branch Formation (Cambrian) at surface, covers < 0.1 % of this area

Purcell Branch Formation - Metadiamictite.

Lithology: metasedimentary rock; meta-conglomerate

Copper Ridge Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Copper Ridge Dolomite - Coarse, dark-gray, knotty dolomite, asphaltic in places, with much gray, medium-grained, well- bedded dolomite; abundant chert; cryptozoans typical. Thickness about 1,000 feet.

Lithology: dolostone (dolomite); chert

Lunga Reservoir Formation (Cambrian) at surface, covers 0.1 % of this area

Lunga Reservoir Formation - Metadiamictite.

Lithology: metasedimentary rock; meta-conglomerate

Marshall Metagranite (Proterozoic Y) at surface, covers 0.3 % of this area

Marshall Metagranite - Medium-granied biotite metagranite

Lithology: granite

Brallier Formation and Harrell Shale, undivided (Devonian) at surface, covers < 0.1 % of this area

Brallier Formation and Harrell Shale, undivided - Brallier Formation : predominantly olive-gray to dark, thickly laminated marine shale, with considerable siltstone and thin sandstone lenses; mainly nonfossiliferous. Harrell Shale: dark gray to black thinly laminated to fissile shale. Calcareous shale and limestone lenses near the base (Tully).

Lithology: shale; siltstone; sandstone; limestone

Marshall Metagranite (Proterozoic Y) at surface, covers < 0.1 % of this area

Marshall Metagranite - Coarse-grained metagranite

Lithology: granite

Holly Corner Gneiss (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Holly Corner Gneiss - Hornblende-biotite gneiss

Lithology: mafic gneiss

Tomstown Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Tomstown Dolomite - Dolomite, in part cherty.

Lithology: dolostone (dolomite); chert

Rockdale Run Formation (Ordovician) at surface, covers < 0.1 % of this area

Rockdale Run Formation - bluish to light gray and brown, thick-bedded dolomite and limestone, containing gray chert and zones of Cryptozoa and Lecanospira.

Lithology: dolostone (dolomite); limestone; chert

Montpelier Metanorthosite (Proterozoic Y) at surface, covers < 0.1 % of this area

Montpelier Metanorthosite - Anorthosite

Lithology: anorthosite

Hampshire Formation (Devonian) at surface, covers < 0.1 % of this area

Hampshire Formation - non-marine shales and fine micaceous sandstones, mostly red to brownish-gray, including siltstone, sandstone and conglomerate. Generally distinguishable from the underlying Chemung by non-marine character and red color.

Lithology: shale; sandstone; siltstone; conglomerate

Hinton Formation (Mississippian) at surface, covers < 0.1 % of this area

Hinton Formation (part of Mauch Chunk Group) - red, green, and medium-gray shale and sandstone, with a few thin limestone beds, including the Avis.

Lithology: shale; sandstone; limestone

New Oxford Formation (Triassic) at surface, covers < 0.1 % of this area

New Oxford Formation - Red, maroon, and gray sandstone, siltstone, and shale; basal conglomerate member: From vicinity of Maryland Rte. 73 and southward, limestone conglomerate with red and gray calcareous matrix; northward, quartz conglomerate with red sandy matrix; estimated total thickness 4,500 feet.

Lithology: shale; sandstone; siltstone; conglomerate

Newark Supergroup; Breccia, mudstone clasts (Upper Triassic) at surface, covers < 0.1 % of this area

Breccia, mudstone clasts

Lithology: sedimentary breccia

Weverton-Loudoun Formation (Cambrian) at surface, covers < 0.1 % of this area

Weverton-Loudoun Formation (Chilhowee Group) - tough quartzitic sandstones, conglomerates, and shale.

Lithology: sandstone; shale; conglomerate

Lynchburg Group - Fanglomerate (Proterozoic Z) at surface, covers < 0.1 % of this area

Lynchburg Group - Fanglomerate

Lithology: conglomerate

Rome Formation (Cambrian) at surface, covers < 0.1 % of this area

Rome Formation - Variegated (red, green, yellow) shale and siltstone with beds of gray, fine-grained sandstone. Maximum exposed thickness 1,500 feet.

Lithology: shale; siltstone; sandstone

Ultramafic Rocks (Proterozoic) at surface, covers < 0.1 % of this area

Ultramafic rocks as exotic blocks within melange units

Lithology: ultramafitite (komatiite)

Biotite-Hornblende Granodiorite (Proterozoic Y) at surface, covers < 0.1 % of this area

Biotite-hornblende granodiorite

Lithology: granodiorite

Hornblende Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Hornblende gneiss

Lithology: mafic gneiss

Arvonia Formation - Slate and porphyroblastic schist (Ordovician) at surface, covers 0.1 % of this area

Arvonia Formation - Slate and porphyroblastic schist

Lithology: slate; schist

Bear Island Granodiorite (Ordovician) at surface, covers < 0.1 % of this area

Bear Island Granodiorite - granodiorite

Lithology: granodiorite; pegmatite

Granite (Proterozoic) at surface, covers 0.1 % of this area

Granite

Lithology: granite; granodiorite

Metavolcanic and Metasedimentary Rocks - Felsic metatuff, mica schist, and gneiss. (Cambrian) at surface, covers < 0.1 % of this area

Metavolcanic and Metasedimentary Rocks - Felsic metatuff, mica schist, and gneiss.

Lithology: felsic metavolcanic rock; mica schist; gneiss

Occoquan Granite (Cambrian-Ordovician) at surface, covers 0.2 % of this area

Occoquan Granite - Granite

Lithology: granite

Chilhowee Group; Weverton Formation (Late Precambrian - Cambrian) at surface, covers < 0.1 % of this area

Weverton Formation - Interbedded white to dark gray, thin-bedded, micaceous, ferruginous, and sericitic quartzites, phyllites, and white, thick-bedded, ledge-making quartzites; some gray to brown ferruginous quartz conglomerate and purple-banded phyllite; thickness approximately 100 feet in south, increases to 425 feet in north.

Lithology: quartzite; phyllite; conglomerate

Brallier Formation (Devonian) at surface, covers < 0.1 % of this area

Brallier Formation - predominantly olive-gray to dark, thickly laminated marine shale, with considerable siltstone and thin sandstone lenses; mainly nonfossiliferous.

Lithology: shale; siltstone; sandstone

Chopawamsic Formation - Foliated felsite (Cambrian) at surface, covers < 0.1 % of this area

Chopawamsic Formation - Foliated felsite

Lithology: felsic volcanic rock

Quaternary Deposits Undivided (Quaternary) at surface, covers < 0.1 % of this area

Quaternary Deposits Undivided - Undifferentiated gray to buff sand and gravel, gray to brown lignitic silt and clay, occasional boulders, and rare shell beds. Surficial deposits occur as intercalated fluvial sands and marsh muds (e.g. in upstream floodplain of the Wicomico and Nanticoke Rivers), well-sorted, stablized dune sands (e.g. eastern Wicomico County), shell-bearing estuarine clays and silts (e.g. lower Dorchester County) and Pocomoke River basin of Worcester County), and beach zone sands (e.g. Fenwick and Assateague Islands). Wisconsin to Holocene in age. Subsurface deposits of pre-Wisconsin age consist of buff to reddish-brown sand and gravel locally incised into Miocene sediments (e.g. Salisbury area), estuarine to marine white to gray sands, and gray to blue, shell-bearing clays (e.g. Worcester County).

Lithology: sand; gravel; silt; clay or mud; dune sand; beach sand

Leucocratic Metagranite (Proterozoic Y) at surface, covers < 0.1 % of this area

Leucocratic metagranite

Lithology: granite

Cove Creek Limestone and Fido Sandstone (Mississippian) at surface, covers < 0.1 % of this area

Cove Creek Limestone and Fido Sandstone - Limestone and calcareous sandstone.

Lithology: limestone; sandstone

Breathitt Formation, middle part (Pennsylvanian) at surface, covers < 0.1 % of this area

Breathitt Formation, middle part

Lithology: sandstone; shale; siltstone; coal; limestone

Swamp Deposits (Quaternary) at surface, covers 0.3 % of this area

Swamp Deposits - Peat, mud, and sand.

Lithology: peat; clay or mud; sand

Metamorphosed Granitic Rock (Ordovician/Cambrian) at surface, covers < 0.1 % of this area

Metamorphosed Granitic Rock (455-540 my) - equigranular to megacrystic, foliated to massive. Includes Toluca Granite.

Lithology: metamorphic rock

Millboro Shale (Devonian) at surface, covers < 0.1 % of this area

Millboro Shale - dark grey to black shale facies of eastern West Virginia. Consists of units: Harrell Shale, Mahantango Formation and Marcellus Formation.

Lithology: shale; black shale

Fauquier Formation - Metaconglomerate (Proterozoic Z) at surface, covers < 0.1 % of this area

Fauquier Formation - Pebble or cobble conglomerate.

Lithology: conglomerate

Shelton Granite Gneiss (Silurian) at surface, covers < 0.1 % of this area

Shelton Granite Gneiss (429 my) - poorly foliated; lineated granitic to quartz monzonitic gneiss.

Lithology: granitic gneiss

Diorite Gneiss (Proterozoic) at surface, covers < 0.1 % of this area

Diorite gneiss

Lithology: gneiss

Catoctin Formation (Cambrian/Precambrian) at surface, covers < 0.1 % of this area

Catoctin Formation - predominantly a greenstone. Basic lava flows, schist and gneiss, containing chlorite, plagioclase, amphibolite, and epidote. Includes minor quantities of arkose and thin clastics. Western subsurface extension presently unknown.

Lithology: greenstone; schist; gneiss; amphibolite; arkose

Interlayered Mafic and Felsic Metavolcanic Rocks - Ferruginous quartzite (Cambrian) at surface, covers < 0.1 % of this area

Interlayered Mafic and Felsic Metavolcanic Rocks - Ferruginous quartzite

Lithology: quartzite

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

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

Lithology: metasedimentary rock; mica schist; marble; granite

Indian Run Formation (Cambrian) at surface, covers < 0.1 % of this area

Indian Run Formation - Metasedimentary melange

Lithology: melange

Phyllonite (Proterozoic-Paleozoic) at surface, covers < 0.1 % of this area

Phyllonite.

Lithology: phyllonite

Pennington Formation, Newman Limestone, Fort Payne Chert, Grainger Formation, Sunbury Shale, Berea Sandstone, and Bedford Shale, undivided; Pennington Formation locally includes sandstone tongue of Lee Formation (Devonian to Pennsylvanian) at surface, covers < 0.1 % of this area

Lithology: limestone; sandstone; siltstone; shale; conglomerate; chert; dolostone (dolomite); black shale

Chopawamsic Formation - Mafic to intermediate metavolcanic rocks (Cambrian) at surface, covers < 0.1 % of this area

Chopawamsic Formation - Mafic to intermediate metavolcanic rocks

Lithology: mafic metavolcanic rock; intermediate metavolcanic rock; tuff

Schaeffer Hollow Granite (Proterozoic Y) at surface, covers < 0.1 % of this area

Schaeffer Hollow granite - Granite

Lithology: granite

Bluestone and Princeton Formations (Mississippian) at surface, covers < 0.1 % of this area

Bluestone and Princeton Formations (part of Mauch Chunk Group) - the Bluestone Formation is mostly red, green, and medium-gray shale and sandstone; Princeton Sandstone is underneath.

Lithology: shale; sandstone

Wissahickon Formation (Undivided) (Late Precambrian (?)) at surface, covers < 0.1 % of this area

Wissahickon Formation (Undivided) - Muscovite-chlorite-albite schist, muscovite-chlorite schist, chloritoid schist, and quartzite; intensely folded and cleaved.

Lithology: schist; quartzite

Buggs Island Pluton (Mississippian Pennsylvanian) at surface, covers 0.2 % of this area

Buggs Island pluton - Granite

Lithology: granite

Border Gneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

border gneiss - Gneiss.

Lithology: gneiss

Polygenetic Melange (Proterozoic) at surface, covers < 0.1 % of this area

Polygenetic melange

Lithology: melange

Phyllite and Metatuff (Proterozoic Z) at surface, covers 0.1 % of this area

Phyllite and metatuff.

Lithology: phyllite; felsic metavolcanic rock

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

Banded Gneiss - interlayered with calc-silicate rock, metaconglomerate, amphibolite, sillimanite-mica schist, and granitic rock.

Lithology: gneiss; metasedimentary rock; amphibolite; mica schist; granite

Robertson River Igneous Suite - Cobbler Mountain alkali feldspar quartz syenite (Proterozoic Z) at surface, covers < 0.1 % of this area

Robertson River Igneous Suite - Cobbler Mountain alkali feldspar quartz syenite

Lithology: alkali syenite

Harrell Shale (Devonian) at surface, covers < 0.1 % of this area

Harrell Shale (part of Millboro Shale) - dark gray to black thinly laminated to fissile shale. Calcareous shale and limestone lenses near the base (Tully).

Lithology: shale; limestone

Trenton Group and Black River Group, undivided (Ordovician) at surface, covers < 0.1 % of this area

Trenton Group and Black River Group, undivided - Trenton Group: dark, crystalline, nodular, and argillaceous limestones, with some metabentonite streaks. Includes the Nealmont, Oranda, Edinburg, and the upper part of the Chambersburg Limestones of northeastern West Virginia; also the Moccasin and Eggleston Formation of Mercer and Monroe Counties. Black River Group: predominantly gray aphanitic limestones, with many bioclastic streaks; siliceous in the lower part.

Lithology: limestone; bentonite

Yorktown Formation and Duplin Formation, Undivided (Tertiary) at surface, covers < 0.1 % of this area

Yorktown Formation and Duplin Formation, Undivided - Yorktown Formation: fossiliferous clay with varying amounts of fine-grained sand, bluish gray, shell material commonly concentrated in lenses; mainly in area north of Neuse River. Duplin Formation: shelly, medium- to coarse-grained sand, sandy marl, and limestone, bluish gray; mainly in area south of Neuse River.

Lithology: clay or mud; sand; limestone

Annandale Group - Lake Barcroft Metasandstone (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Annandale Group - Lake Barcroft Metasandstone

Lithology: metasedimentary rock

Elk Park Plutonic Group - Biotite quartz monzonite (Proterozoic Y) at surface, covers 0.5 % of this area

Elk Park Plutonic Group - Biotite quartz monzonite

Lithology: quartz monzonite

Fine Creek Mills Granite (Proterozoic) at surface, covers < 0.1 % of this area

Fine Creek Mills granite - Granite

Lithology: granite

Rockfish River Pluton (Proterozoic Z) at surface, covers < 0.1 % of this area

Rockfish River Pluton - Granodiorite.

Lithology: granodiorite

Metatonalite (Proterozoic) at surface, covers < 0.1 % of this area

Metatonalite

Lithology: tonalite; granodiorite; quartz diorite

Lowland Deposits (Quaternary) at surface, covers < 0.1 % of this area

Lowland Deposits - Gravel, sand, silt, and clay. Medium- to coarse-grained sand and gravel; cobbles and boulders near base; commonly contains reworked Eocene glauconite; varicolored silts and clays; brown to dark gray lignitic silty clay; contains estuarine to marine fauna in some areas (includes in part Pamlico, Talbot, Wicomico and Sunderland Formations of earlier reports); thickness 0 to 150 feet.

Lithology: gravel; sand; silt; clay or mud

Striped Rock Granite (Proterozoic Z) at surface, covers < 0.1 % of this area

Striped Rock Granite - Biotite granite and syenite.

Lithology: granite; syenite

Newark Supergroup; Conglomerate, carbonate clasts (Upper Triassic) at surface, covers < 0.1 % of this area

Conglomerate, carbonate clasts

Lithology: conglomerate

Yorkshire Formation (Cambrian) at surface, covers < 0.1 % of this area

Yorkshire Formation - Polygenetic melange

Lithology: melange

Metaperidotite, Metapyroxenite, and Hornblende Metagabbro (Proterozoic Y) at surface, covers < 0.1 % of this area

Metaperidotite, Metapyroxenite, and Hornblende Metagabbro - Serpentinite is metaperidotite, Hornblende metagabbro

Lithology: serpentinite; greenstone

Georgetown Intrusive Suite (Cambrian) at surface, covers < 0.1 % of this area

Georgetown Intrusive Suite - Tonalite, quartz gabbro, quartz diorite, metapyroxenite, and hornblendite.

Lithology: tonalite; gabbro; greenstone; hornblendite

Waynesboro Formation (Cambrian) at surface, covers < 0.1 % of this area

Waynesboro Formation - variegated shale and sandstone, commonly red or brown. Middle zone contains much dolomite and limestone. Contains the Olenellus fauna of Early Cambrian age, although its upper portion may be of Middle Cambrian age.

Lithology: shale; sandstone; limestone; dolostone (dolomite)

Dale City Quartz Monzonite (Cambrian) at surface, covers < 0.1 % of this area

Dale City Quartz Monzonite- Quartz monzonite and quartz monzodiorite.

Lithology: quartz monzonite; quartz monzodiorite

Phyllite and Metasiltstone (Proterozoic Z) at surface, covers 0.1 % of this area

Phyllite and metasiltstone.

Lithology: phyllite; meta-argillite

Catoctin Formation - Metarhyolite (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Catoctin Formation- Metarhyolite

Lithology: rhyolite

Catoctin Metabasalt (Late Precambrian) at surface, covers < 0.1 % of this area

Catoctin Metabasalt - Thick-bedded metabasalt with amygdaloidal layers and secondary veins of quartz, calcite, and epidote; interbedded green tuffaceous phyllite and blue amygdaloidal metaandesite.

Lithology: meta-basalt; phyllite

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

Biotite Gneiss and Schist - 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.

Lithology: biotite gneiss; mica schist; amphibolite; calc-silicate rock; granite

Catoctin Formation - Metabasalt breccia (high titanium) (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Catoctin Formation - Metabasalt breccia (high titanium)

Lithology: meta-basalt

Marcellus Formation (Devonian) at surface, covers < 0.1 % of this area

Marcellus Formation (part of Millboro Shale) - predominantly gray-black to black thinly laminated non-calcareous pyritic shale. Contains one or more thin-bedded limestones, including the Purcell Member of Pennsylvania.

Lithology: black shale; limestone

Surficial Deposits, Undivided (Quaternary) at surface, covers < 0.1 % of this area

Surficial Deposits, Undivided - sand, clay, gravel, and peat deposited in marine, fluvial, eolian, and lacustrine environments. Quaternary deposits not shown at altitudes greater than approx. 205 feet above mean sea level (Suffolk Scarp, in part).

Lithology: lake or marine deposit (non-glacial); eolian; sand; clay or mud; gravel; peat

Rockwood Formation and Clinch Sandstone (Silurian) at surface, covers < 0.1 % of this area

Rockwood Formation - Brown to maroon shale, thin gray siltstone and sandstone, and thin lenticular layers of oolitic and fossiliferous red hematite. Thickness 200 to 800 feet; and Clinch Sandstone - Clean, white, well-sorted sandstone; locally gray siltstone and shale. Combined Rockwood and Clinch thicknesses about 700 feet.

Lithology: sandstone; shale; siltstone

Chepultepec Dolomite (Ordovician) at surface, covers < 0.1 % of this area

Chepultepec Dolomite - Light-gray, fine-grained, well-bedded dolomite, moderately cherty; fine-grained limestone locally in upper part; quartz sandstone beds at base. Average thickness about 800 feet.

Lithology: dolostone (dolomite); limestone; sandstone

Pocahontas Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Pocahontas Formation - Sandstone, siltstone, shale, and coal.

Lithology: sandstone; siltstone; shale; coal

Garnetiferous Leucocratic Metagranite (Proterozoic Y) at surface, covers 0.1 % of this area

Garnetiferous leucocratic metagranite

Lithology: granite

Hyco Formation (Proterozoic Z) at surface, covers 0.2 % of this area

Hyco Formation - Lithic and crystal metatuff

Lithology: metavolcanic rock; schist

Lee Formation (Pennsylvanian - Mississippian) at surface, covers < 0.1 % of this area

Lee Formation - Quartzarenite, sandstone, conglomerate, shale, siltstone, and coal.

Lithology: arenite; sandstone; conglomerate; shale; siltstone; coal

Omar Formation - Accomack Member: (Quaternary) at surface, covers 0.3 % of this area

Omar Formation - Accomack Member: sand, gravel, silt, clay, and peat; at altitudes to 50 ft.

Lithology: sand; gravel; silt; clay or mud; peat

Buckingham Complex - Metamorphosed mafic and ultramafic rocks (Proterozoic Z-Pennsylvanian) at surface, covers < 0.1 % of this area

Buckingham Complex - Metamorphosed mafic and ultramafic rocks

Lithology: metamorphic rock

Newark Supergroup, Dan River Group; Pine Hall Formation (Triassic) at surface, covers < 0.1 % of this area

Pine Hall Formation - sandstone, mudstone, and conglomerate, yellowish orange to brown.

Lithology: sandstone; mudstone; conglomerate

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

Gneiss and schist.

Lithology: gneiss; schist

Harpers Formation (Cambrian) at surface, covers < 0.1 % of this area

Harpers Formation (Chilhowee Group) - greenish-gray phyllite, with interbeds of fine-grained quartzite.

Lithology: phyllite; quartzite

Porphyritic Granite (Proterozoic) at surface, covers < 0.1 % of this area

Porphyritic granite

Lithology: granite

Antietam Formation (Cambrian) at surface, covers < 0.1 % of this area

Antietam Formation (Chilhowee Group) - gray to white quartzite, sandstone and quartz-schist; thick-bedded, and resistant; contains Scolithus.

Lithology: quartzite; sandstone; schist

Kanawha Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Kanawha Formation (part of Pottsville Group) - sandstone (approx 50%), shale, siltstone, and coal. Contains several marine zones. Becomes more shaly westward in the subsurface. Extends from the top of the Homewood Sandstone to the top of the Upper Nuttall Sandstone. Includes the Stockton (Mercer), Coalburg, Winifrede, Chilton, Williamson, Cedar Grove, Alma, Peerless, Campbell Creek, Powellton, Eagle, Gilbert, and Douglas coals.

Lithology: sandstone; shale; siltstone; coal

Pocahontas Formation (Pennsylvanian) at surface, covers < 0.1 % of this area

Pocahontas Formation (part of Pottsville Group) - sandstone, approx. 50%, with some shale, siltstone, and coal. Extends from the top of the Flattop Mountain Sandstone to the top of the Mississippian. Includes from bottom upward Pocahontas coals Nos. 1 through 7.

Lithology: sandstone; shale; siltstone; coal

Tomstown Dolomite (Cambrian) at surface, covers < 0.1 % of this area

Tomstown Dolomite - thick-bedded, blue-gray, aphanitic, saccharoidal, and splintery dolomite, weathering coffee-brown; some siliceous limestone and black chert. Contains commercial beds of white, pure, low-silica dolomite.

Lithology: dolostone (dolomite); limestone; chert

Trondhjemite (Cambrian-Ordovician) at surface, covers < 0.1 % of this area

Trondhjemite

Lithology: trondhjemite

Annandale Group - Accotink Schist (Proterozoic Z-Cambrian) at surface, covers < 0.1 % of this area

Annandale Group - Accotink Schist.

Lithology: schist; meta-argillite

Metamorphosed Granitic Rock (Cambrian/Late Proterozoic) at surface, covers < 0.1 % of this area

Metamorphosed Granitic Rock (520-650 my) - megacrystic, well foliated, locally contains hornblende; Fountain intrusive.

Lithology: metamorphic rock

Garnet-Graphite Paragneiss (Proterozoic Y) at surface, covers < 0.1 % of this area

Garnet-graphite paragneiss

Lithology: paragneiss

Granitoid Rocks (Proterozoic) at surface, covers < 0.1 % of this area

Granitoid blocks as exotic blocks within melange units

Lithology: granitoid

Kyanite Schist (Proterozoic) at surface, covers < 0.1 % of this area

Kyanite schist

Lithology: schist

Metatonalite (Ordovician) at surface, covers < 0.1 % of this area

Metatonalite

Lithology: felsic gneiss

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