doi:10.7916/D8WW7MC3Notes on an early chart of Long Island Sound and its approachesTownshend, Charles Hervey, 1833-1904bookstextHydrographic surveying--Long Island Sound (N.Y. and Conn.)--Maps.Long Island Sound (N.Y. and Conn.)--Surveys.Long Island Sound (N.Y. and Conn.)--Maps.