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Mineral Resources > Online Spatial Data > Geology > by state > Ohio Geology

Geologic units in Darke county, Ohio

Lockport Dolomite (Silurian) at surface, covers 69 % of this area

Lockport Dolomite - Dolomite, shades of white to medium gray, medium to massive bedded, fine to coarse crystalline; fossiliferous; vuggy.

Lithology: dolostone (dolomite)

Louisville Limestone through Brassfield Limestone (Silurian) at surface, covers 0.6 % of this area

Louisville Limestone through Brassfield Limestone - Sexton Creek Limestone at base in Kentland area and on cross-section

Lithology: limestone

Salina Group (Silurian) at surface, covers 12 % of this area

Salina Group - 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.

Lithology: dolostone (dolomite); shale; evaporite

Cincinnati Group as used by Wickstrom (1990) (Ordovician) at surface, covers 10 % of this area

Cincinnati Group as used by Wickstrom (1990) - Shale, dolomite and limestone, interbedded. Various shades of gray; thin to medium bedded; Data from core holes. Occurs beneath glacial drift.

Lithology: shale; dolostone (dolomite); limestone

Clinton and Cataract Groups, Undivided (Silurian) at surface, covers 8 % of this area

Clinton and Cataract Groups, Undivided - Dolomite, limestone and shale, interbedded. Various shades of gray, olive green, yellow and reddish-gray; laminated to thick bedded; argillaceous, glauconitic, pyritic, ferruginous and/or phosphatic; locally fossiliferous. Data from core holes. Occurs beneath glacial drift.

Lithology: shale; limestone; dolostone (dolomite)