COLORADO EXPLORING EXPEDITION. 



PRELIMINARY REPORT 



FIRST LIEUT. J. C. IVES, 



TOPOGRAPHICAL ENGINEERS, 



T* 



CAPTAIN A. A. HUMPHREYS, 



TOPOGRAPHICAL ENGINEERS, 



IN CHARGE OF THE OFFICE OF EXPLORATIONS AND SURVEYS, 

 WAR DEPARTMENT, NOVEMBER 1858. 



Washington, November 1, 1858. 



Captain: I have the honor to submit, for the information of the 

 department, the following brief synopsis of a portion of the results 

 of the expedition organized under my command for the exploration 

 of the Rio Colorado of the west. 



I sailed from San Francisco for the mouth of the Colorado river on 

 the 1st of November, 1857, in the quartermaster's schooner used in 

 transporting stores to the head of the Gulf of California. On board 

 were the property and supplies belonging to the expedition, and also 

 the materials for constructing a small iron steamer, to be employed in 



