Chesapeake Group (DE*,DC*,MD*,NC*,VA*)
(alphabetical): Bacons Castle Formation (NC,VA), Bethany Formation (DE), Calvert Formation (DE*,MD*,NC,VA*), Cat Hill Formation (DE-subsurface), Choptank Formation (DE,MD*,VA*), Chowan River Formation (NC*,VA*), Eastover Formation (MD*,NC*,VA*), Old Church Formation (MD*,VA*), St. Marys Formation (DE*,MD*,VA*), Yorktown Formation (MD*,NC*,VA*).
Tertiary (late Oligocene to late Pliocene)*
Type area: areas adjacent to Chesapeake Bay (Darton, 1891).
Atlantic Coast basin*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.
"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 ([ ]).