Chesapeake Group; St. Marys Formation

Greenish-blue to yellowish-gray sandy clay and fine-grained argillaceous sand; thickness 0 to 80 feet.
State Maryland
Name Chesapeake Group; St. Marys Formation
Geologic age Miocene
Lithologic constituents
Unconsolidated > Fine-detrital > Clay
Unconsolidated > Coarse-detrital > Sand
Stratigraphic units Chesapeake Group

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 Calvert - Saint Mary's