Washington, D. C., April 6, 1857. 
Sir I have the honor to submit, herewith, a Report upon the Geology of the route for 
railroad to the Pacific, examined hy the Expedition under your command in 1853. 
Very respectfully, your obedient servant, 
WM. P. BLAKE, 
. Geologist and Mineralogist of the Expedition. 
Lieutenant R. S. Williamson, 
Corps Topographical Engineers. 
