Columbia subject headings:
Chesapeake and Ohio Canal National Historical Park--Maps.
Geology--Chesapeake and Ohio Canal National Historical Park--Maps.
Geology--Great Falls of the Potomac (Md. and Va.)--Maps.
Geology--Virginia--Great Falls Park--Maps.
Great Falls Park (Va.)--Maps.
Great Falls of the Potomac (Md. and Va.)--Maps.
Maps.
Harvard subject headings:
Chesapeake and Ohio Canal National Historical Park--Maps.
Geology--Chesapeake and Ohio Canal National Historical Park--Maps.
Geology--Great Falls of the Potomac (Md. and Va.)--Maps.
Geology--Virginia--Great Falls Park--Maps.
Great Falls Park (Va.)--Maps.
Great Falls of the Potomac (Md. and Va.)--Maps.
Princeton subject headings: