Summary of Content: Title continues: ”Prepared by Command of Maj. Gen. George B. Mc.Clellan U.S.A. Commd’g Army of the Potomac A.A. Humphreys Brig. Gen. and Chief of Top. Engr’s. Photographed at the Coast Survey Office. A faint brown-line print on four pieces of joined wove paper. Inscribed to General Samuel P. Heintzelman by Abbot.