Geologic units in Pickaway county, Ohio

Ohio Shale (Devonian) at surface, covers 49 % 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.

Salina Group (Silurian) at surface, covers 23 % 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.

Columbus Limestone (Devonian) at surface, covers 9 % 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.

Maxville Limestone; Rushville, Logan, and Cuyhoga Formations, Undivided (Mississippian) at surface, covers 9 % of this area

Shale, siltstone, and sandstone, interbedded; various shades of gray, yellow to brown weather similar color; sandstone, silty to granular, local stringers of quartz pebbles. Shale, clayey to silty, locally fossiliferous. Medium to dark gray, thin to thick bedded limestone locally preserved at top of interval where unit crops out in southern half of state. Lithologies percentages vary in different areas where unit crops out; laterial and vertical gradation common at regional scale.

Sunbury Shale, Berea Sandstone, and Bedford Shale, Undivided (Devonian and/or Mississippian) at surface, covers 6 % of this area

Shale and sandstone; upper 10 to 50 feet shale; black to brown, weathers light brown; carbonaceous; thin, planar bedding. Underlain by 10 to 50 feet sandstone; brown, weathers light brown to reddish brown; thin to thick bedded, planar to lenticular bedding; minor shale interbeds. Basal 80 to 100 feet shale and interbedded sandstone; gray to brown, weathers light gray to light brown; thin to medium bedded, planar to lenticular bedding; thick. Interval thickness ranges from 100 to 200 feet.

Tymochtee and Greenfield Formations, Undivided (Silurian) at surface, covers 3 % of this area

Dolomite, olive-gray to yellowish- brown, thin to massive bedded, upper two-thirds commonly contains brownish-black to gray shale laminae; locally developed brecciated zones in lower one third.

Black Hand Sandstone Member of Cuyahoga Formation (Mississippian) at surface, covers 0.6 % of this area

Sandstone and conglomerate; yellow-gray to white, weathers shades yellow, brown, red, and gray; very fine grained to pebbles, mostly medium to coarse grained with lenses and layers of pebbles; massive to crossbedded to laminated; grades laterally into shale and siltstone; quartzose.