MI-19 Nell's Topographical and Township Map of the State of Colorado Download Publication Details Vintage map depicting Colorado in 1885 during the peak of the state’s mining activities. Including physiography, land grid, railroads, and townsites it was compiled from U.S. government surveys and other authoritative sources and produced in Philadelphia, PA, in 1885. Black line reproduction. 1 plate (1:665,280). Digital PDF download. MI-19D Citations Chain, Hardy and Company. “MI-19 Nell’s Topographical and Township Map of the State of Colorado.” Miscellaneous Investigations. Philadelphia PA: J. L. Smith, 1885. https://coloradogeologicalsurvey.org/publications/nells-topographical-township-map-colorado.