Chesapeake Group  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Cenozoic
 ...upper Cenozoic
 ....Chesapeake Group
RTOligocene
 Pliocene
 Pleistocene
 Miocene
 Virginia
 North Carolina
 Maryland
 Delaware
 Calvert Formation
 Choptank Formation
 Chowan River Formation
 Eastover Formation
 Saint Marys Formation
 Yorktown Formation
SNVirginia, North Carolina, Delaware and E Maryland. At one time considered, middle and upper Miocene, it ranges from Oligocene to Pleistocene. Indexed with age or ages as applicable. Added to Thesaurus in 1985.