Geologic units in Erie county, Ohio

Ohio Shale (Devonian) at surface, covers 40 % of this area

Shale; brownish black to greenish gray, weathers brown; carbonaceous to clayey, laminated to thin bedded, fissile parting; carbonate and/or siderite concretions in lowermost 50 feet; petroliferous odor; 250 to 500+ feet thick. Includes Olentangy Shale south of central Delaware Co.

Berea Sandstone and Bedford Shale, Undivided (Devonian) at surface, covers 19 % of this area

Sandstone and shale; upper portion sandstone; brown, weathers light brown to reddish brown; thin to thick bedded, planar to lenticular bedding; minor shale interbeds; 5 to 75 feet thick, locally 100 to 125 feet thickness in Lorain, Cuyahoga, and Medina Counties; lower portion shale; gray to brown, locally reddish brown; thin to medium bedded, planar to lenticular bedding; interbedded siltstone and sandstone, ripple marks in siltstone beds; 80 to 180 feet thick, locally thin to absent where Berea Sandstone is thick.

Columbus Limestone (Devonian) at surface, covers 14 % of this area

Limestone and dolomite; gray to brown, weathers brown; massive bedding; upper 2/3 fossiliferous, gray limestone, lower 1/3 brown dolomite; 0 to 105 feet thick.

Delaware Limestone (Devonian) at surface, covers 14 % of this area

Limestone; gray to brown; thin to massive bedded; argillaceous partings, nodules and layers, carbonaceous, petroliferous odor; as much as 45 feet thick.

Salina Group (Silurian) at surface, covers 6 % of this area

Dolomite, gray, yellow-gray to olive-gray, laminated to thin bedded; occasional thin bed and laminae of dark gray shale and anhydrite and/or gypsum; brecciated zones in part.

Plum Brook Shale (Devonian) at surface, covers 5 % of this area

Shale and argillaceous limestone; gray; thin bedded fossiliferous; 0 to 40 feet thick.

Prout Limestone (Devonian) at surface, covers 1 % of this area

Limestone; olive gray; dolomitic in part; hard, siliceous; irregular bedding; pyrite, glauconite and phosphatic bone fragments at upper contact; 0 to 9 feet thick. Devonian (Givetian) Prout Limestone in OH contains corals superficially similar to those of lower part of Jaycox Shale Member of Ludlowville Formation in NY (Oliver, in press).