2. "Mason Island Ferry," National Park Service, ; Angus William McDonald, Report of Col. A.W. McDonald: relative to his mission to England, March 1861, published online by University of Pittsburgh, Digital Research Library, 2007, pp.13-15, ; Paul B. Cissna, "Historical and Archeological Study of the George Washington Memorial Parkway From the Theodore Roosevelt Memorial Bridge to the Lorcom Lane Turnabout on Spout Run Parkway, Arlington, Virginia," Occasional Report #4, Regional Archeology Program - National Capital Region, National Park Service, Washington, D.C., 1990, pp.34-35, ; "A Brief History of Shepherdstown," Historic Shepherdstown and Museum, ; "Thomas Swearingen Ferry & James Rumsey Bridge," C&O Canal Trust, , Since 1964, five studies and at least five private ferry service providers have examined the feasibility of passenger ferry service on the Potomac River. During the same period, no ferry services have been started To attract projected patronage, the ferry service would have to operate at a speed that is competitive with other modes of travel., The Potomac Science Center (PSC) is located in Woodbridge, Virginia, on the beautiful Belmont Bay near the mouth of the Occoquan River and is a destination for environmental science research along the Chesapeake Bay watershed..