Hell Gate and its approaches. From a trigonometrical survey under the direction of F.R. Hassler and A.D. Bache, Superintendents of the Survey of the Coast of the United States. Triangulation by Edmund Blunt, assistant. Topography by H.L. Whiting, assistant. Hydrography by the parties under the command of D.D. Porter & M. Woodhull, Lts., U.S. Navy. Published in 1851. A.D. Bache, Superintendent. Reduction of topography for engraving by C. Mahon, of hydrography by J.R.P. Mechlin. Topography engraved by A. Rolle, F. Dankworth & G. McCoy; lettering by J. Knight. Electrotype copy no. 1 by G. Mathiot, U.S.C.S. (with logo) U.S. Coast Survey Office.
