1. Geologic map of the Potomac River Gorge, Great Falls Park, Virginia, and part of the C&O Canal National Historical Park, Maryland [computer file] Yale Public content 2000. 2002-06-01T04:00:00Z. 2023-02-11T04:46:15Z. Geological Survey (U.S.). The Survey. English. Public. Virginia, Great Falls Park, Chesapeake and Ohio Canal National Historical Park, and Great Falls of the Potomac (Md. and Va.).