Report of the Geological Exploration of the Fortieth Parallel, Volume VI: Microscopical petrography
Professional Papers of the Engineer Department, U.S. Army, No. 18. Report of the Geological Exploration of the Fortieth Parallel made by order of the Secretary of War according to acts of Congress of March 2, 1867, and March 3, 1869, under direction of Brig. and Bvt. Major General A. A. Humphreys, Chief of Engineers. This Professional Papers series is comprised of 7 monograph volumes.