386 COSMOS. 



long. 112 9' 30". Even at this point the chain of the 

 Kocky Mountains maintains a considerable height (5977 feet) ; 

 but, from the many deep river-beds in the direction of Flat- 

 head Eiver (Clarke's Fork), it soon decreases to a more regu- 

 lar level. Clarke's Fork and Lewis or Snake River unite in 

 forming the great Columbia River, which will one day prove 

 an important channel for commerce. (Explorations for a Rail- 

 road from the Mississippi River to the Pacific Ocean, made in 

 1853-1854, vol. i., p. 1Q7.) 



As in Bolivia, the eastern chain of the Andes farthest re- 

 moved from the sea, that of Sorata (21,287 feet) and Illimani 

 (21,148 feet), furnish no volcano now in a state of ignition, 

 so also, in the western parts of the United States, the vol- 

 canic action on the coast chain of California and Oregon is 

 at present very limited. The long chain of the Rocky Mount- 

 ains, at a distance from the shores of the South Sea vary- 

 ing from 480 to 800 geographical miles, without any trace 

 of still existing volcanic action, nevertheless shows, like the 

 eastern chain of Bolivia, in the vale of Yucay,* on both of 

 its slopes volcanic rock, extinct craters, and even lavas in- 

 closing obsidian, and beds of scoriae. In the chain of the 

 Rocky Mountains which we have here geographically de- 

 scribed, in accordance with the admirable observations of 

 Fremont, Emory, Abbot, Wislizenus, Dana, and Jules Mar- 

 cou, the latter, a distinguished geologist, reckons three groups 

 of old volcanic rock on the two slopes. For the earliest no- 

 tices of the vulcanicity of this district we are also indebted to 

 the investigations made by Fremont since the years 1842 and 

 1843 (Report of the Exploring Expedition to the Rocky Mount- 

 ains in 1842, and to Oregon and North California in 1843-44, 

 p. 164, 184, 187, and 193). 



On the eastern slope of the Rocky Mountains, on the south- 

 western road from Bent's Fort, on the Arkansas River, to 

 Santa Fe del Nuevo Mexico, lie two extinct volcanoes, the 

 Raton Mountains! with Fisher's Peak, and the hill of El 

 Cerrito, between Galisteo and Pera Blanca. The lavas of 

 the former cover the whole district between the Upper Ar- 

 kansas and the Canadian River. The Perperino and the, 

 volcanic scoriae, which are first met with even in the prairies, 



* See above, p. 279. 



f According to the road-map of 1855, attached to the general report 

 of the Secretary of State, Jefferson Davis, the Raton Pass rises to an 

 elevation of as much as 7180 feet above the level of the sea. Compare 

 also Marcou, Resume explicatif d'une Carte Geol, 1855, p, 113. 



