|Name||Point Pleasant Formation|
Sedimentary > Clastic > Mudstone > Shale (Bed)Limestone(60%) and shale(40%) interbedded; gray to bluish gray weathers light gray; planar to lenticular, thin to medium bedded; 0 to 80 feet thick.
Sedimentary > Carbonate > Limestone (Bed)Limestone(60%) and shale(40%) interbedded; gray to bluish gray weathers light gray; planar to lenticular, thin to medium bedded; 0 to 80 feet thick.
|Comments||Secondary unit description from USGS Lexicon website (ref. OH017) and OH009: Authors suggest that the interval from the top of the relatively clean limestone of the Trenton (Curdsville Member of the Lexington Limestone) to the base of the predominantly shale strata of the basal Cincinnati group (Kope Formation) be called the Point Pleasant Formation in the subsurface of OH. In northwestern OH, the Point Pleasant ranges in thickness from 0 in Sandusky and Mercer Cos to approximately 200 ft on the eastern edge of the study area. Contacts with both the underlying Trenton Limestone and the overlying Kope Formation are gradational. Unit consists of interbedded dark argillaceous limestone, brown to black calcareous shales and brachiopod coquina layers. Relative amount of limestone decreases toward the top of the formation and the shale becomes light to dark gray. "The rocks of the Clays Ferry Formation, the Point Pleasant Tongue of the Clays Ferry Formation, and the Logana and Grier Members of the Lexington Limestone, as defined by Cressman (1973) appear to be stratigraphically equivalent to the upper Trenton in northwestern OH and are herein called the Point Pleasant Formation." (Wickstrom and others, 1992).|
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.
Wickstrom, L.H., Gray, J.D. and Stieglitz, R.D., 1992, Stratigraphy, structure, and production history of the Trenton Limestone (Ordovician) and adjacent strata in northwestern Ohio: Ohio Division of Geological Survey Report of Investigations, no.143, 78 p.
de Witt, Wallace, Jr., 1993, Principal oil and gas plays in the Appalachian basin (Province 131), IN Evolution of sedimentary basins; Appalachian basin: U.S. Geological Survey Bulletin, 1839-I, p. I1-I37.
USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/
|Counties||Brown - Butler - Clermont - Hamilton|