Conococheague Limestone

Dark blue, laminated, oolitic, argillaceaous, and siliceous limestone, algal limestone, and flat-pebble conglomerate; siliceous shale partings; some sandstone and dolomite; thickness 1,600 to 1,900 feet.
State Maryland
Name Conococheague Limestone
Geologic age Upper Cambrian to Lower Ordovician
Lithologic constituents
Sedimentary > Carbonate > Limestone
Sedimentary > Clastic > Conglomerate
Sedimentary > Carbonate > Dolostone
Sedimentary > Clastic > Sandstone
Sedimentary > Clastic > Mudstone > Shale

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 Washington