Ohio River between Mound City and Cairo / surveyed by the party of F.H. Gerdes, asst. assigned by A.D. Bache, Supdt. U.S. Coast Survey to act under orders of Rear Admiral D.D. Porter, U.S.N., commanding Mississippi Squadron.United States Coast Survey1864Depths shown by soundings and contours.Shows railroads and some surface structures.Vegetation shown pictorially.cartographic