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Mineral Resources > Online Spatial Data > Geology > by state > West Virginia Geology

Geologic units in Monroe county, West Virginia

[Additional scientific data in this geographic area]

Maccrady Formation and Pocono Group, undivided (Mississippian) at surface, covers 0.6 % 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

Chemung Group (Devonian) at surface, covers 7 % 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

Hinton Formation (Mississippian) at surface, covers 8 % 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

Greenbrier Group (Mississippian) at surface, covers 22 % 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

Juniata and Oswego Formations (Ordovician) at surface, covers 2 % 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

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

McKenzie Formation and Clinton Group (Silurian) at surface, covers 2 % 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

Bluefield Formation (Mississippian) at surface, covers 28 % 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

Juniata, Reedsville, Trenton, and Eggleston Formations (Ordovician) at surface, covers < 0.1 % 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

Maccrady Formation (Mississippian) at surface, covers 2 % of this area

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.

Lithology: shale; sandstone; mudstone; limestone; chemical

McKenzie Formation, Clinton Group and Tuscarora Sandstone, undivided (Silurian) at surface, covers 2 % 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

Tuscarora Sandstone (Silurian) at surface, covers 0.6 % 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

Martinsburg Formation (Ordovician) at surface, covers 3 % 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

Beekmantown or Lower Ordovician Group (Ordovician) at surface, covers 4 % 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

Knox Group (Cambrian-Ordovician) at surface, covers < 0.1 % 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

St. Paul Group (Ordovician) at surface, covers 2 % 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)

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

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

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

Oriskany Sandstone and Helderberg Group, undivided (Devonian) at surface, covers 0.4 % 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

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

Brallier Formation - Micaceous shale, siltstone, and sandstone.

Lithology: shale; siltstone; sandstone

Harrell Shale (Devonian) at surface, covers 0.6 % 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

Moccasin or Bays Formation through Blackford Formation (Ordovician) at surface, covers < 0.1 % 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

Mahantango Formation (Devonian) at surface, covers 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

Millboro Shale (Devonian) at surface, covers 0.9 % 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

Marcellus Formation (Devonian) at surface, covers 2 % 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

Brallier Formation (Devonian) at surface, covers 2 % 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

Oriskany Sandstone and Huntersville Chert (Devonian) at surface, covers 2 % 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

Pocono Group (Mississippian) at surface, covers 6 % 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

Keefer, Rose Hill, and Tuscarora Formations (Silurian) at surface, covers < 0.1 % 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

Trenton Group and Black River Group, undivided (Ordovician) at surface, covers 2 % 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

Chemung Formation (redefined as Foreknobs Formation) (Devonian) at surface, covers < 0.1 % of this area

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

Lithology: shale; sandstone; conglomerate

Lower Devonian and Silurian Formations Undivided (Silurian-Devonian) at surface, covers 0.1 % 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

Millboro Shale and Needmore Formation (Devonian) at surface, covers < 0.1 % 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

Ridgeley Sandstone, Helderberg and Cayugan Groups (Silurian-Devonian) at surface, covers < 0.1 % of this area

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

Lithology: limestone; sandstone; shale