Geologic units in Putnam county, Ohio

Detroit River Group (Devonian) at surface, covers 2 % of this area: Detroit River Group - Dolomite; brown to gray; medium to thick bedded; laminated; nodules or interbeds of anhydrite and/or gypsum; basal part becomes sandy dolomite or fine-grained sandstone; as much as 170 feet thick.
Lithology: dolostone (dolomite); evaporite; sandstone
Tymochtee and Greenfield Formations, Undivided (Silurian) at surface, covers 1 % of this area: Tymochtee and Greenfield Formations, Undivided - 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.
Lithology: dolostone (dolomite); shale
Salina Group (Silurian) at surface, covers 97 % 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