Antietam Formation  search
BTChronostratigraphic Units
 .Phanerozoic
 ..Paleozoic
 ...Cambrian
 ....Lower Cambrian
 .....Antietam Formation
RTVirginia
 Pennsylvania
 Maryland
 West Virginia
 Chilhowee Group
SNIn Chilhowee Group. Maryland, SE Pennsylvania, Virginia, West Virginia.