ptbrien,
The sign you pass states: "A law of 1704 provided that three notches of equal distance marked on the trees indicated a road leading to a ferry." The sign is in the wrong stretch of Rte. 235, as the original was from the end of Mattapany Street to Millstone Landing, which is since 1941 part of the Naval Air Station, but was for over 200 years the ferry boat landing to Solomons and to the road north to Annapolis.
Henry