United States. Geological Survey. U.S.G.S. Alternate title: Lambertville, N.J.-PA. Relief shown by 20 feet contour intervals. Topography of New Jersey part by the Geological Survey of New Jersey 1887-88. Culture revised in 1904. Topography of Pennsylvania part by Ira M. Flocker 1905. Verso: legend and explanatory notes, "The topographic maps of the United States".