from a Chilean government survey in 1870, with additions and corrections in 1886 by Lieutenant F.M. Symonds, and Naval Cadet C.M. McCormick, U.S.N. of the U.S.S. Mohican, Commander B.F. Day, U.S.N. comdg. ; drawn by Gregor Noetzel and A. Klakring ; engraved by M. Franke and R.H. Gaskins