Corryville member named as middle member of McMillan formation. Also referred to as CHILOPORELLA NICHOLSONI beds. Consists of 60 ft of interbedded thin limestone and yellowish, also blue, shale. Overlain by Mount Auburn or PLATYSTROPHIA LYNX beds and underlain by Bellevue or MONTICULIPORS MOLESTA beds. Age is Late Ordovician.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Grant Lake Limestone and Grant Lake Formation (of the informal Cincinnati group) 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. 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. The Grant Lake Limestone 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. Corryville consists primarily of interbedded, planar- to lenticular-bedded limestone and planar-bedded, platy- to flaggy-parted, sparsely fossiliferous shale. Shale percentage ranges from 34 to 74 percent. Upper contact with the Mount Auburn and Straight Creek Members ranges from sharp to gradational. Thickness of the Corryville in southwestern OH ranges from <6 m to >21 m.

Source: GNU records (USGS DDS-6; Reston GNULEX).

Corryville Member of Grant Lake Formation in Clermont Co., OH, is used in this report. Underlies Mount Auburn Member.

Source: GNU records (USGS DDS-6; Reston GNULEX).