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National Geologic Map Database

Geologic Unit: Calvert

Usage:

Calvert Formation of Chesapeake Group (DE*,MD*,VA*)


Subunits:

(alphabetical): Alloway Clay Member (DE*,MD*), Calvert Beach Member (MD*,VA*), Fairhaven Member (MD*,VA*), Plum Point Marl Member (MD*), Popes Creek Sand Member (DE*,MD*,VA*).


Geologic age:

late Tertiary (early to middle Miocene)*


Type section, locality, area and/or origin of name:

Calvert Co., especially Calvert Cliffs, southern MD (Shattuck, 1902).


AAPG geologic province:

Atlantic Coast basin*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).