CXXXV1 NOTES. 



plnce at more recent and very different periods from eacli other, and often in very 

 different directions. These groups of mountains, thus rising from a high plat- 

 form, are so connected in the Rocky Mountains as to form a rampart extending 

 through eight degrees of latitude; and being rendered conspicuous to a great 

 distance by conical summits, chiefly trachytic, twelve and thirteen thousand feet 

 high, they produce on the traveller the more impression (it appears to me), 

 because to the eye they have, illusively, the effect of rising direct from a low- 

 land plain. Although in the Cordilleras of South America, of which I know a 

 considerable portion from having myself explored them, it has been customary, 

 from the time of La Condamine, to speak of a double and triple range (the 

 Spanish expression " Cordilleras de los Andes " refers to such arrangement and 

 division); yet it is not to be forgotten that here also the directions of particular 

 groups, whether as long ridges or as a series of domes, are by no means generally 

 parallel to each other or to the direction of the entire chain. 



( Ml ) p. 395. Fremont, Explor. Exped. p. 281- 288: Pike's Peak, lat. 

 38 50', drawn in p. 114; Long's Peak, in 40 15'; the ascent of Fremont's 

 Peak. 13,570 feet high, is described in p. 70. The Wind Eiver Mountains take 

 their name from the sources of a tributary to the Big Horn River, whose waters 

 unite with those of the Yellow Stone River which falls into the Upper Missouri 

 in 47 58' N., 103 05' W. See the drawings of mountains having much mica- 

 slate and granite, in pp. 66 and 70. A change of direction takes place in the 

 chain of the Rocky Mountains between the parallels of Pike's Peak and Lewis' 

 and Clark's Pass, when it turns more to the west. This circumstance is recalled 

 for the sake of comparison with the chain of the Ural which, according to the 

 arduous examinations of my friend and travelling companion Colonel Ernst Hof- 

 mann, turns eastward near its northern extremity. Its length is fully 1020 

 geographical miles from the Truchmenian mountain Airuck-Tagh in 48^ N. to 

 the Sablja Mountains in 65 N.; in the course of these seventeen degrees of 

 latitude it deviates but little from the meridian of 59 E. of Greenwich, but in 

 65 it bends, as aforesaid, to the eastward, so as to reach the meridian of 66 E. 

 in the parallel of 67 N. Compare Ernst Hofmann, Der nbrdliche Ural und 

 d;is Kusten-Gebirge Pac-Choi, 1856, S. 191 and 297305, with Humboldt, 

 Asie Centrale (1843), t. i. p. 447. 



( Ms ) p. 396. Kosmos, Bd. iv. S. 321 (present volume, p. 277). 



( M3 ) p. 397. The Raton Pass, according to an itinerary map of 1855 be- 

 longing to the General Report of the Secretary of State, Jefferson Davis, is 7180 

 feet above the sea. Compare also Marcou, Re'sume explicatif d'une Carte ge*ol. 

 1855, p. 113. 



( M4 ) p. 397. We distinguish, proceeding from east to west, the ridges of 



