This is a manuscript map entitled “A Plan of the Environs of Brooklyn Showing the Position of the Rebel Lines and Defenses on the 27th of August, 1776” drawn up by Loyalist Engineer George S. Sproule, born in Long Island in 1741 and an assistant to map maker Samuel Holland. The map seems to draw on Bernard Ratzer’s 1766 topographical survey work, with Sproule giving more detail of hills. Sproule shows more detailed fortification works than the British Military Headquarters Map of 1782, making it possible that some fortifications shown, such as the double bank of earthworks at Degraw Street near Brouwers Mill and fortifications on Red Hook Lane near the Seabrings Red Hook mill ponds were planned, rather than actually built. The original map is at the Clements Library, University of Michigan. Scan kindly provided by Bob Furman of the Brooklyn Preservation Council
