Tonoloway Limestone

Gray, thin-bedded limestone, dolomitic limestone, and calcareous shale; thin sandstone member in east 20 feet above base; fossiliferous; thickness 400 feet in east, increases to 600 feet in west.
State Maryland
Name Tonoloway Limestone
Geologic age Silurian
Lithologic constituents
Sedimentary > Carbonate > Limestone
Sedimentary > Clastic > Mudstone > Shale
Sedimentary > Clastic > Sandstone

Cleaves, E.T., Edwards, J., Jr., and Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.

In 1995 the Water Resources Division of the U.S. Geological Survey digitized the geologic map of Maryland from the 1968 paper map (Reference MD001). Information about products from the Maryland Geological Survey can be found at

NGMDB product
Counties Allegany - Washington