USA Map - 1881 Progress Map of the US Geographical Survey-West of the 100th Meridian to accompany the annual report of 1st Lieut. M.M. Macomb, 4th artillery US Army, scale 1 inch to 94.71miles, covering the seasons of 1869 and 1871 to 1879, showing areas published etc., line of expeditions, explorations and surveys shown in red with names of officers and date of surveys also abandoned Military Posts, Telegraph lines, forts etc, 25.5"x20.5" on thick paper, folded