[67] Acts of Assembly, 1946, Chapter 26. _Code of Virginia, 1950_, Title 7.1, Sec. 10. This law is in effect today. It provides that the boundary line "shall begin at a point where the northwest boundary of the District of Columbia intercepts the high-water mark of the Virginia shore of the Potomac River and following the present mean high-water mark; thence in a southeasterly direction along the Virginia shore of the Potomac River to Little River, along the Virginia shore of Little River to Boundary Channel, along the Virginia side of Boundary Channel to the main body of the Potomac River, along the Virginia side of the Potomac River across the mouths of all tributaries affected by the tides of the river to Second Street, Alexandria, Virginia, from Second Street to the present established pierhead line, and following said pierhead line to its connection with the District of Columbia-Maryland boundary line; that whenever said mean high-watermark on the Virginia shore is altered by artificial fill and excavations made by the United States, or by alluvion or erosion, then the boundary shall follow the new mean high-water mark on the Virginia shore as altered, or whenever the location of the pierhead line along the Alexandria water front is altered, then the boundary shall follow the new location of the pierhead line." The Act also provided that all the land on the Virginia side of the Potomac lying between the boundary line as now adopted and the mean high water mark as it existed on January 24, 1791 (wherever that was!) should be ceded to the State of Virginia. The United States, however, reserved concurrent jurisdiction over this area. Here the matter rests very uneasily today. The exact line was surveyed, monumented, and mapped by the U.S. Coast and Geodetic Survey over the years 1946-1947.[68] However, the working agreements reached by the law enforcement officials of the various jurisdictions concerned have not always proven satisfactory. The long history of the location of the Potomac River boundary of Arlington County cannot yet be said to have reached its end. [68] Unpublished Report dated March 27, 1947, from Lt. Comdr. Roswell C. Bolstad, Chief of Party, on Project G-815, Coast and Geodetic Survey, Department of Commerce. _Postscript--Towns in Arlington County_ Of the three towns which have lain within Arlington County, the only one whose limits have been of importance to the territorial extent of the County is Alexandria. Nonetheless, to complete the record, some mention should be made of the Town of Potomac and the Town of Falls Church, the first of which lay wholly within Arlington, and the second, partly so. Falls Church is the older town. It was chartered by the General Assembly on March 30, 1875.[69] The charter set forth the boundaries as: