286 Transactions of the American Institute. 



dition no published narrative exists, inasmuch as the reports made by 

 tlie chief of our party and the members of the scientific coq^s 

 attached to the expedition are lying, -where they have remained since 

 the commencement of tlie war, in the archives of the war depart- 

 ment. Tliese, if published, together with the important reports of 

 Colonel Reynolds and General Warren, on tlie country bordering the 

 Upper Missouri, would be of much interest to geographers, and, if 

 in possession of the public, would be of great economic value, inas- 

 much as they give minute and accurate accounts of a large portion of 

 our country very little known, yet into which our people are rapidly, 

 but, for want of tlie information these reports could furnish, blindl_y 

 pushing their wa3\ 



The last of our Colorado expeditions was designated as the San 

 Juan expedition, from the fiict that its free field of exploration lies 

 for the most part near or on the San Juan river — a stream almost 

 unknown to the whites until we explored it, and yet a river as large 

 as the Connecticut — whose banks once sustained a population of 

 more than 100,000, now utterly solitary and deserted. 



To enable you to fix in your mind the geographical position of the 

 region I am about to describe to you, I will call your attention to 

 this map of our western territories. 



Here you see the Colorado discharging itself into the Gulf of 

 California, while it rises in the Rock}- Mountains 1,500 miles toward 

 the north-east, a large streain but one whose length isdisproportioned 

 to its volume of water. 



The Colorado has two principal tributaries. Green river, which 

 rises in Wyoming, and crosses the line of the Union Pacific rail- 

 road, and Grand river, which drains the western portion of Colorado 

 Territory. These, uniting in the south-eastern part of Utah, form 

 the Colorado proper. From this point to the great bend of the 

 Colorada, at the mouth of the Rio Virgin, is what is known as the 

 Great Caiion of the Colorado, nowhere less than 3,000 and in some 

 places 5,000 feet deep. Below the Great Bend the river runs through 

 a low country, and one of the most singular in its topography of any 

 that I have ever seen. This is a continuation of the great trough 

 which is partially filled by the Gulf of California, lying between the 

 Sierra Nevada, which composes the peninsula of Lower California on 

 the west side, and the Black and Cerbat mountahis, in Arizona, on 

 the eastern side. Tin's, for the most i)art, is a desert country ; and 

 here, just about the head of the gulf, lies the " Colorado Desert," as 



