</ 





7f 



^^naf Nliise*^-^ 



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 TIIK DIRECTION OF 



BRIG. AND BVT. MAJOR GENERAL A. A. HUMPHREYS, 



CHIEF OF ENGINEERS 



CLARENCE KING, 



U. S. GEOLOGIST. 



I-II 



