Oriskany Group including Ridgeley Sandstone and Shriver Chert

Oriskany Group, including Ridgeley Sandstone - White, medium- to coarse-grained, fossiliferous, calcareous orthoquartzite; thickness 160 feet in west. Medium to dark gray cherty, arenaceous limestone in east; thickness 50 feet; and Shriver Chert - Dark gray, brown, and black silty shales, cherty shales, and nodular and bedded black chert; fossiliferous; thickness 170 feet in west, upper boundary gradational with Ridgeley. Thickness 14 feet in east where the lower Shriver intertongues with the Licking Creek Limestone Member of the Helderberg Formation
State Maryland
Name Oriskany Group including Ridgeley Sandstone and Shriver Chert
Geologic age Devonian
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Quartziteorthoquartzite
Minor
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Carbonate > Limestone
Sedimentary > Chemical > Chertblack chert
Sedimentary > Clastic > Mudstone > Shale > Black-shale
Stratigraphic units Oriskany Group
References

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at http://www.mgs.md.gov/.

NGMDB product
Counties Allegany - Washington