12 Historical 



the desert of Gobi. Towards the west, they collect in the Oxus 

 which carries them to the Lake of Aral. 



Other chains, of a considerable absolute elevation, rise above 

 these high plateaux. On the northeast, Thian-Schan, whose cul- 

 minating point is Bogda-Oola, borders the great desert, and joins 

 Altai and the mountainous ridge which separates the basin of the 

 Arctic Ocean from that of the Pacific. To the southwest, Hindou- 

 Kouch, which prolongs Karakorum and is fully as high at-the begin- 

 ning, joins the chain of Elburs by the mountains of Korassan. To 

 the south, Soliman-Kouch stretches along the river Indus. 



America. The orographic system of America forms a striking 

 contrast to that of Asia. Here there is no central group from which 

 diverging chains extend, like so many gigantic arms. On the con- 

 trary, a ridge, certain summits of which are dominated only by 

 those of the Himalayas, stretches along the shores of the Pacific 

 Ocean from Patagonia to Alaska. In the part farthest toward the 

 south, the Cordillera is simple and of moderate height; but towards 

 the north its average elevation gradually increases and reaches two 

 maximum points, in Bolivia and at the Equator. At the same time, 

 while its western side remains consistently abrupt, so that moun- 

 tains 6000 meters high are sometimes less than 20 leagues from the 

 sea, there appear on the eastern side foothills whose size constantly 

 increases, so that in Bolivia there is a group 100 to 150 leagues wide 

 with an average height of 4000 meters, in which there stand out 

 particularly two parallel chains bounding the lofty valley of the 

 lake of Titicaca (3915 meters) . These two chains, with their inter- 

 mediate valley cut by knots, where rise the Maranon and the 

 Ucayali, on which are built La Paz, Puno, Cuzco, Quito, and other 

 cities, first drop, spreading out to the knot of Pasco, then rise again 

 and reach their highest point just at the Equator. Here the eastern 

 ridge forks in its turn and ends at the sea, by the chain of Vene- 

 zuela and the Nevada of Santa-Marta, whose principal summit, the 

 Horqueta (5500 meters) , rises almost on the edge of the sea of the 

 Antilles. 



The western Cordillera, considerably reduced in height, next 

 forms the isthmus of Panama, stretches along the Pacific in Central 

 America, rises again, and spreads out in Mexico. Thence extend, 

 as in South America, two great parallel chains, this time much 

 farther from each other, and much less lofty. On the east, the 

 ridge of the mountains of New Mexico, of the Rocky Mountains, 

 of the Mountains of the Chipways, separates the waters of the 

 Atlantic from those of the Pacific. The western chain remains near 



