NOTES ON THE ROCKY MOUNTAIN RANGES IN COL- 

 ORADO TERRITORY. 



The Cordilleras of North America — the mountain-system of its west- 

 ern coast — are one with the Cordilleras of the southern continent, in 

 having their general axis, a prolongation of the Andes, both as respects 

 direction and actual topographical connection by the ranges and pla- 

 teaus of Central America ; while the fact that both are due to a common 

 cause is shown by their bearing the same relations to the great basin or 

 the Pacific Ocean, whose subsidence is undoubtedly connected with their 

 origin. 



The Cordilleras of North America consist of several chains and many 

 ranges and table-lands, forming a system, because they are but the features 

 and minor dependencies' of one great general uplift of Western America — 

 au elongated plateau upon whose face they are arranged in lines parallel 

 with the axis or along the western side. 



The two leading mountain-chains of the plateau are the chain of the 

 Sierra Nevada and Cascade ranges and the chain of the Eocky Moun- 

 tains ; one standing directly upon its western edge ; the other, the 

 Eocky Mountain chain, forming the true crest of the great continental 

 wave of upheaval, which, taken as a whole, is the Cordillera system. 

 Between these chains, and even outside of them, are lesser chains, 

 groups, and ranges. 



The system has its greatest expansion between the thirty-sixth and 

 forty-first parallels, where the breadth is about 1,350 miles, including the 

 Coast ranges on the Pacific shores and the eastern slope of the xjlateauthat 

 descends from the foot of the Rocky Mountains to the proper basin of 

 the Missouri, about 150 miles west of that river. The mountains alone are 

 about 950 miles broad. This measurement is perpendicular to the general 

 axis of this part of the system, whose direction may be taken at about 

 north 15° to 20° west. 



As this is the region of greatest breadth of the Northern Cordilleras, 

 it is also the zone of greatest elevation, containing the highest peaks in 

 the United States and the larger part of the area above 12,000 feet. The 

 most powerful force of upheaval seems to have acted across the system 

 in a belt 300 miles broad, whose central line runs west-southwest from 

 Denver, Colo., to Monterey, 100 miles south of San Francisco. In 

 crossing California it includes the highest parts of the Sierra Nevada, 

 the Mount Whitney cluster of peaks, and those near the Yosemite ; in 

 Utah the highest parts of the Wasatch chain ; while in Colorado the 

 eastern end of the belt crosses the great meridional chain of the Eocky 

 Mountains. In this Territory, therefore, we have the grandest uplifts of 

 the chain. 



Approaching Colorado from the east, rising gradually up 500 miles 

 of monotonous plain, the mind is well prepared for the sensation that 

 awaits one on reaching Denver. The South Platte Eiver here flows 

 nearly north. Denver, situated on its eastern bank, slopes toward the 

 mountains. 



