Estill Shale

Shale and minor dolomite interbedded, reddish to greenish gray, weathers light gray, planar to irregular bedding, thin to thick bedded, 30 to 180 feet thick. Diagnostic features include dominance of shale and the units susceptibility to be unstable on slopes and cause landslides.
State Ohio
Name Estill Shale
Geologic age Silurian
Lithologic constituents
Major
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.
Minor
Sedimentary > Carbonate > Dolostone (Bed)Estill Shale: minor interbedded dolomite.
References

Slucher, E.R., (principal compiler), Swinford, E.M., Larsen, G.E., and others, with GIS production and cartography by Powers, D.M., 2006, Bedrock geologic map of Ohio: Ohio Division of Geological Survey Map BG-1, version 6.0, scale 1:500,000.

NGMDB product
Counties Adams - Brown - Clinton - Greene - Highland - Pike - Ross