376 NATURAL PHENOMENA OF THE EQUATORIAL REGIONS'. 



Mountains. The height of the loftiest mountains is so trifling conu 



pared with the radius of the Earth, that it has had very littl« 

 influence ou the grand phenomena of geology: but it is 

 perceptible with regard to a small part of the Earth's sur- 

 face, and the law according to which the different rock- 

 formations are arranged above the level of the sea. The 

 equatorial regions exhibit both the loftiest summits, and the 

 most extensive plains. We cannot therefore ascribe to the 

 rotary motion of the globe this group of mountains. Be- 

 sides, the chain of the Andes at its two extremities extends 

 toward the poles as far as 29 Q or 30 p *. This chain is very 

 unequal: in many places it is not above 200 met. [218*57 

 yards] high; but in four places it attains a colossal height. 

 These are in 17° south latitude ; under the equator in the 

 kingdom of Quito; atMexico, in the latitude of 19 Q north; 

 and opposite Asia, in 60° north lat. This height varies 

 from 50.0Q to 6000 met. [5464 to 65*57 yards]. The chain 

 of the Aiidts is not less astonishing for its bulk, than for its 

 height. Near the volcano of Antisana, at the height of 

 4000 met. [4371 yards], Mr. von H. found a plain twelve 

 leagues in circumference. In some parts this chain is from 

 40 to CO leagues broad. | 



Chimborazo forms one extremity of a colossal group. 

 The chain that extends to the south stretches so far toward 

 the ocean, that the islands near the continent may be con- 

 sidered as fragments of it. On the north the Cordillera se- 

 parates into, three branches. The easternmost forms the 

 group of Santa Martha and Merida. The westernmost, 

 from which we are furnished with platina, forms a group 

 near the city of Mexico, some of the peaks of which, as 

 Popocatepec and Oribaza, exceed' 5300 met. [57S2 yards]. 

 This chain afterward diminishes considerably, but in the vi- 

 cinity of Asia it forms a fourth group, in which Mount 

 St. Elias is 55 12 met. [6024 yards] high. In these latitudes 

 the Andes appear to have a subterranean communication 

 with the volcanoes of Kamtsehatka. 



In their interior structure the mountains of the equator 

 anite almost every kind of rock discovered in the rest of 



* It should be 50° or 60°. C. 



the 



