Plan of Fort Niagara . . . May 1761 by Geo. Demler'. Part of Lake Ontario River. . 'Plan of Fort Niagara . . . May 1761 by Geo. Demler'. Laid down 2 May, 1761 by Geo. Demler. 1:1200. 'Scale to the plan 500 feet' (= 6 inches). Inset, profile of the fo