Sketch Showing the Progress of the Survey in Section II and III. Primary Triagulation between Long Island and the Blue Ridge

A very nice map showing the primary triangulations from the northern part of Virginia, upper Chesapeake, Pennsylvania, and east to Long Island Sound. IMPORTANT NOTE: All of our United States Coast Survey (USCS), United States Coast & Geodetic Survey (USC&GS), and similar maps and charts have been professionally unfolded and flattened using humidity baths, semi-permeable membrane, and drying blotter techniques. Most others you typically see on eBay have not been, and worse, are quickly and crudely unfolded for the low-quality photos you see. Unfolding these maps in that way is damaging and weakens them. Please be aware.