Chesapeake Group; Choptank Formation (MDTch;5)

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
Original map label	Tch
Primary rock type	sand
Secondary rock type	silt
Other rock types	sandstone; coquina
Lithologic constituents	Major Unconsolidated > Fine-detrital > Silt Unconsolidated > Coarse-detrital > Sand 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 Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD
Geographic coverage	Calvert - Caroline - Dorchester - Saint Mary's - Talbot