Map of the Gettysburg Battlefield prepared by authority of the Hon. Daniel S. Lamont, Russell A. Alger, Elihu Root, Secretaries of War, under the direction of the Gettysburg National Military Park Commission, Lt. Col. John P. Nicholson Chairman, John B. Bachelder, Esq., Major William M. Robbins, Brig. General William H. Forney, Major Charles A. Richardson. Original survey by Lt. Col. E. B. Cope, Engineer, S. A. Hammond and H.W. Mattern Ass't Engineers, reduced from the original by H. W. Mattern. Gettysburg National Military Park Commission.