Office of the U. S. Geological Exploration 



OF THE Fortieth Parallel, 



New York, April, 1877. 



General: Herewith I have the honor to transmit Volume IV of the 

 Reports of this Exploration, composed of Memoirs on Palaeontology, by 

 Messrs. F. B. Meek, James Hall and R P. Whitfield; also on Ornithology, 

 by Robert Ridgway. 



Very respectfully, your obedient servant, 



CLARENCE KING, 



Geologist-in-charge. 



Brig. Gen. A. A. Humphreys, 



Chief of Engineers U. S. Army, 



Washington, B. Q. 



XI-XII 



