Cedarville, Springfield, Euphemia, and Laurel Dolomites; Massie Shale, Undivided

Cedarville Dolomite, white to gray to blue gray weathers gray; abundant intercrystalline, moldic, and vuggy porosity, massive bedded, 0 to 100 feet thick. Diagnostic features include porosity, cliff-forming nature of unit, and pentamerid brachiopod fossil zone near contact with Springfield Dolomite. Springfield Dolomite, gray to tan, mottled with brownish gray, massive bedded where unweathered and layered brick-like where weathered, 5 to 10 feet thick. Euphemia Dolomite, dolomite to dolomitic limestone, gray to bluish gray, massive bedded, 5 to 15 feet thick. Diagnostic features include large, blocky bedding where weathered and cliff forming nature. Massie Shale, gray to bluish gray, minor limestone and dolomite beds, calcareous, slakes easily, planar to irregular bedding, thin to thick bedded, 0 to 10 feet thick. Diagnostic feature includes calcareous shale with limestone and dolomite. Laurel Dolomite, gray to tan, weathers brown, argillaceous to nonargillaceous, wavy bedding, thin to medium bedded, 5 to 10 feet thick. Interval ranges from 115 to 140 feet thick. Euphemia Dolomite averages 1.6 to 2.6 m in thickness. Environment of deposition was normal marine offshore, free from clastic influence; similar to Cedarville Dolomite. Unconformably overlies Massie Shale. Correlates with Bisher Formation to the southeast. Age is Wenlockian (Ausich, 1987).
State Ohio
Name Cedarville, Springfield, Euphemia, and Laurel Dolomites; Massie Shale, Undivided
Geologic age Silurian
Lithologic constituents
Major
Sedimentary > Carbonate > Dolostone (Bed)Cedarville: white to gray to blue gray weathers gray; abundant intercrystalline, moldic, and vuggy porosity, massive bedded, 0 to 100 feet thick; pentamerid brachiopod fossil zone near contact with Springfield. Springfield: gray to tan, mottled with brownish gray, massive bedded where unweathered and layered brick-like where weathered, 5 to 10 feet thick. Euphemia: dolomite to dolomitic limestone, gray to bluish gray, massive bedded, 5 to 15 feet thick. Massie: gray to bluish gray, minor limestone and dolomite beds, calcareous, slakes easily, planar to irregular bedding, thin to thick bedded, 0 to 10 feet thick. Laurel: gray to tan, weathers brown, argillaceous to nonargillaceous, wavy bedding, thin to medium bedded, 5 to 10 feet thick.
Incidental
Sedimentary > Clastic > Mudstone > Shale (Calcareous)Massie Shale: gray to bluish gray, calcareous, slakes easily, planar to irregular bedding, thin to thick bedded, 0 to 10 feet thick.
Sedimentary > Carbonate > Limestone (Bed)Euphemia Dolomite: dolomite to dolomitic limestone, gray to bluish gray, massive bedded, 5 to 15 feet thick. Massie Shale: gray to bluish gray, minor limestone and dolomite beds, calcareous.
Comments Secondary unit description from USGS Lexicon website (ref. OH017) and OH008.
References

Slucher, E.R., (principal compiler), Swinford, E.M., Larsen, G.E., and others, with GIS production and cartography by Powers, D.M., 2006, Bedrock geologic map of Ohio: Ohio Division of Geological Survey Map BG-1, version 6.0, scale 1:500,000.

Ausich, W.I., 1987, John Bryan State Park, Ohio; Silurian stratigraphy, IN Biggs, D.L., ed., North-central Section of the Geological Society of America, Centennial field guide: Geological Society of America, North-Central Section, The Decade of North American Geology (DNAG), Centennial Field Guide, v. 3, p. 419-422.

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/

https://ngmdb.usgs.gov/Geolex/search

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Counties Clinton - Fayette - Greene - Highland