|Name||Grant Lake and Fairview Formations, Miamitown Shale, Undivided|
Sedimentary > Clastic > Mudstone > Shale (Bed)Limestone (50%) and shale (50%), interbedded; gray to bluish-gray weathers light gray to yellowish-gray;, planar to lenticular, thin to medium bedded in lower half; wavy to irregular to nodular, thin to thick bedded in upper half; fossiliferous. Interval of shale (90%) with limestone (10%), as much as 35 feet thick, near middle of unit.
Sedimentary > Carbonate > Limestone (Bed)Limestone (50%) and shale (50%), interbedded; gray to bluish-gray weathers light gray to yellowish-gray;, planar to lenticular, thin to medium bedded in lower half; wavy to irregular to nodular, thin to thick bedded in upper half; fossiliferous. Interval of shale (90%) with limestone (10%), as much as 35 feet thick, near middle of unit.
|Comments||Secondary unit descriptions from USGS Lexicon website (ref. OH017) and OH012, OH013, and OH014: Grant Lake Limestone and Grant Lake Formation are adopted by the Ohio Geological Survey for southwestern OH. The shale content of the Grant Lake Limestone progressively increases between Maysville, KY, and Cincinnati, OH. The term Grant Lake Formation is used where the unit becomes predominantly shale (50 to 60%). The Grant Lake Formation is divided into (ascending) Bellevue, Corryville, and Mount Auburn Members. Name is applied in Butler, Hamilton, and Warren Cos. and in portions of Brown, Clermont, and Clinton Cos. Type section is designated as the composite section exposed along Stonelick Creek in Clermont Co., OH (Ohio Geological Survey measured sections 16831, 16836, 16837, and 16852). Ohio Geological Survey cores 868, 2537, 2620, 2627, 2981, and 2982 are designated as principal reference sections. The Grant Lake Limestone is redefined to include those stratigraphic sequences that contain less than a mean value of 50% calcareous, fossiliferous shale. Road cuts created for KY Rte 11, near Maysville, are designated as principal reference sections. Unit is divided into the Bellevue, Corryville, and Straight Creek (new name) Members. Name is applied in Adams and Highland Cos. and in portions of Brown, Clermont and Clinton Cos. The Grant Lake overlies the Miamitown Shale or Fairview Formation and underlies the informal Arnheim formation, all of the informal Cincinnati group (Schumacher and others, 1991). Fairview Formation: The Kope-Fairview-Bellevue succession is the first of three major progradational units that compose the Cincinnatian Series in the Cincinnati, OH, area. Each succession is interpreted as a mixed siliciclastic-carbonate ramp. The Kope Formation is the most distal facies of the ramp complex. The Fairview Formation is the intermediate-depth lithofacies in the upward-shoaling succession. Unit is 20 to 35 m thick and is composed of subequal proportions of thin-bedded, fine to coarse skeletal limestone and gray, thin-bedded shales and minor siltstone. The North Bend Tongue is separated from the main body of the Fairview by the Wesselman Tongue of the Kope. The North Bend becomes indistinguishable 15 to 20 km northwest of Cincinnati. Faunal assemblages in the Fairview are marked by changes in type and morphologic character due to an increase in physical energy. Larger brachiopods and ramose trepostome bryozoans are common. Interfingers to the southeast with Calloway Creek Formation and to the northwest with the upper part of the Kope Formation. Age shown as largely Maysvillian; Edenian very locally south of the Ohio River (Jennette and Pryor, 1993). The Miamitown Shale in southwestern OH consists of shale and mudstone with minor interbeds of limestone. Fossils within this unit include gastropods and pelecypods. Thickness is 5 to 35 feet. Conformably overlies the Fairview Formation and underlies the Bellevue Limestone. The Miamitown is of Late Ordovician age (Wahlman, 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.
Frey, R.C., 1995, Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati arch region of Kentucky, Indiana, and Ohio, IN Pojeta, John, Jr., ed., Contributions to the Ordovician paleontology of Kentucky and nearby states: U.S. Geological Survey Professional Paper, 1066-P, p. P1-P126.
Schumacher, G.A., Swinford, E.M. and Shrake, D.L., 1991, Lithostratigraphy of the Grant Lake Limestone and Grant Lake Formation (Upper Ordovician) in southwestern Ohio: Ohio Journal of Science, v. 91, no. 1, p. 56-68.
Jennette, D.C. and Pryor, W.A., 1993, Cyclic alternation of proximal and distal storm facies; Kope and Fairview Formations (Upper Ordovician), Ohio and Kentucky: Journal of Sedimentary Petrology, v. 63, no. 2, p. 183-203.
Wahlman, G.P., 1992, Middle and Upper Ordovician symmetrical univalved mollusks (Monoplacophora and Bellerophontina) of the Cincinnati arch region, IN Pojeta, John, Jr., ed., Contributions to the Ordovician paleontology of Kentucky and nearby states: U.S. Geological Survey Professional Paper, 1066-O, p. O1-O203.
USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/
|Counties||Butler - Clermont - Clinton - Greene - Hamilton - Montgomery - Preble - Warren|