Estill Shale and Drowning Creek Formation, Undivided (OHSed;0)

Estill Shale and Drowning Creek Formation, Undivided - Estill Shale, reddish to greenish gray, weathers light gray, minor interbedded dolomite, planar to irregular bedding, thin to thick bedded, 30 to 180 feet thick. Forms unstable slopes susceptible to landslides. Drowning Creek Formation; dolomite with minor shale; bluish gray to gray weathers yellowish orange; argillaceous and silty in part; planar to lenticular, thin to thick bedded; 20 to 90 feet thick.

State	Ohio
Name	Estill Shale and Drowning Creek Formation, Undivided
Geologic age	Silurian
Original map label	Sed
Primary rock type	shale
Secondary rock type	dolostone (dolomite)
Other rock types
Lithologic constituents	Major Sedimentary > Carbonate > Dolostone (Bed)Estill Shale: minor interbedded dolomite. Drowning Creek Formation: dolomite, bluish gray to gray weathers yellowish orange; argillaceous and silty in part; planar to lenticular, thin to thick bedded; 20 to 90 feet thick. Sedimentary > Clastic > Mudstone > Shale (Bed)Estill Shale: reddish to greenish gray, weathers light gray, planar to irregular bedding, thin to thick bedded, 30 to 180 feet thick. Drowning Creek Formation: minor shale.
Map references	Digital Ohio map from CD produced as a result of a contract between the U.S. Geological Survey and the Ohio Geological Survey. Released with permission of the Ohio Geological Survey, June 2005.
Unit references	Digital Ohio map from CD produced as a result of a contract between the U.S. Geological Survey and the Ohio Geological Survey. Released with permission of the Ohio Geological Survey, June 2005. File of unit descriptions received from Ohio Geological Survey.
Geographic coverage	Adams