Map of explorations and surveys south of the Central Pacific Railroad made by the U.S. Army Corps of Topographical Engineers, 1871

'Preliminary topographical map embracing in skeleton a portion only of the notes from surveys made in accordance with Par.II Special Orders No. 109 War Dept., March 18th, 1871 and letter of instructions of Brig. General A.A. Humphreys, Chief of Eng'rs. dated March 23rd, 1871. Conducted under the immediate direction of 1st Lieutenant Geo. M. Wheeler, Corps of Eng'rs., assisted by 1st Lieutenant D.W. Lockwood, Corps of Eng'rs. and 2nd Lieutentant D.A. Lyle, 2nd U.S. Artillery, during the summer and fall of 1871. Louis Nell, chief topographer and draughtsman.'' At head of map: 'Explorations in Nevada and Arizona. U.S. Engineer Department.' In lower left corner: 'Note: This map is a hasty and partial compilation from the topographical data already received, many still remaining en route. Upon it is projected in skeleton the groundwork of the area examined. All points except the prominent astronomical positiions are subject to lsight modification upon the final map.' Shows area through central Nevada, eastern California, and central Arizona. Relief shown by hachures. Published by the War Dept. Scale [ca. 1:1,520,640]. 1 in. to 24 miles (W 118°--W 109°/N 41°--N 32°).