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Chesapeake Group; Choptank Formation

Chesapeake Group; Choptank Formation - Interbedded brown to yellow very fine-grained to fine-grained sand and gray to dark bluish-green argillaceous silt; locally indurated to calcareous sandstone; prominent shell beds; thickness 0 to 50 feet.
State Maryland
Name Chesapeake Group; Choptank Formation
Geologic age Miocene
Primary rock type sand
Secondary rock type silt
Other rock types sandstone; coquina
Lithologic constituents
Major
Unconsolidated > Coarse-detrital > Sand
Unconsolidated > Fine-detrital > Silt
Minor
Sedimentary > Clastic > Sandstone
Incidental
Sedimentary > Carbonate > Limestone > Coquinaprominent shell beds
Map references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unit references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD
Counties Calvert - Caroline - Dorchester - Saint Mary's - Talbot