ی یکی اسرد جرخ 
LETTER TO THE SECRETARY OF ۰ 
War DEPARTMENT, OFFICE OF EXPLORATIONS AND SURVEYS, - 
Washington, D. C., March 2, 1858. 
Sir: I transmit laesit a report from Lieutenant G. K. Warren, Topographical Engineers, 
exhibiting the data and authorities from which was compiled the map of United States territory 
between the Mississippi river and the Pacific ocean, intended to illustrate the reports upon the 
Pacific railroad explorations. 
It contains a brief account of all the explorations of our territory west of the Mississippi 
river of approved authority, which will be not only valuable to the officers of the corps, but, it 
is thought, interesting to the public. 
The laborious task of compiling the map and preparing the report has been performed by 
Lieutenant Warren while occupied with other duties of an onerous character. The more 
carefully his work is examined, the more apparent will be the industry, care, and sound 
judgment with which it has been executed. 
Very respectfully, your obedient servant, 
A. A. HUMPHREYS, 
; Captain Topographical Engineers, in charge. 
Hon. J. B. Fuoyp, | 
Secretary of War, Washington, D. C. 
