United States. Geological Survey. U.S.G.S. Alternate title: Mass.-Conn.-R. I. Webster. Polyconic projection. Relief shown by 20 feet contour interval and spot heights. Surveyed in 1886-7. Surveyed in cooperation with the states of Massachusetts and Connecticut. Triangulation by the U.S. Coast and Geodetic and Borden Surveys. Verso: The topographic maps of the United States.