From a trigonometrical survey under the direction of A.D. Bache, Superintendent of the Survey of the Coast of the United States ; triangulation by C.O. Boutelle, Assistant ; topography by H.L. Whiting, Asst. ; hydrography by the party under the command of Lieut. Comdg. C.R.P. Rodgers, U.S.N. Asst. ; Redd. Drng. By P. Witzel ; Engd. By R.F. Bartle & E.A. Mädel