1876 progress map of the U.S. Geographical Surveys west of the 100th meridian : to accompany the annual report of 1st lieut. George M. Wheeler, Corps of Engineers, U.S. Army / 1st lieut. Geo. M. Wheeler, Corps of Engineers, U.S. Army, in charge ; under the direction of Brig. Gen. A.A. Humphreys, chief of engineers, U.S. Army.