III. 



GENEEAL EEATUEES OF THE COLOEADO BASIN. 



I 



The Three Great River Basins west of the Rocky Mountains compared. — The 

 Wahsatch Mountains.^ — Lieutenant lyes' Expedition, — The Colorado Basi? 

 consists of a succession of lofty, arid Table-lands. — Dr. Ne^^vherry on th^ 



Origin of the Strata forming these Table-lands. — The Drainage passes^ 



The Colorado Plateau, and the Great Canon whicte 



To what causes are due^th'^ 



-The MogoUor 



usually through Canons. 



passes through it. — How are Canons formed ? 



The basin of tV 



Table-land features of the Country? — Central Arizona. 



San Francisco, Pina-leiio, Sierra Madre, and other Mountains in tl 



1 



Colorado Basin. — Yalleys of the Eio Colorado. — Valley of the Eio Gila, 



The country lying between the Hocky Mountains and tY^, 

 Sierra Xevacia consists of tlu-ee regions- 

 Columbia Eivcr forms the northern^ that of the Colorado ti^*^, 

 eastern and soutliernj and that of the Great Basin systet 

 the western. There is not very much difference between tn f 

 areas of these districts. 



The basin of the Columbia Eiver has an area of about 

 That of the Colorado 



That of the Great Basin 



For the sake of comparison, the area of France 



That of the Mississippi Basin 



That of the Eio Grande del Xorte Basin 



13 



Square miles. 



230,000 

 200,000 

 280,000 



210,000 



1,400,000 



210,000 



-i 



i 



As we do not enter the basin of the Columbia Eiyer in 

 any part of onr trayels, I shall confine my observations exclu- 



sively to the 



of country ; only reniarkin 



here, that the divide which senarates •the Cohunbian Basin 



t, 



from the Great Basi 



system passes from the southern 



emity of the Elue Mountains of Oregon in a .south-Tresterly 



w 1 



