

NATURAL PHENOMENA OF THE EQUATORIAL REGIONS. 377 



the globe. The arrangement of their strata too is perfectly equatorial 

 similar. Granite forms the base of the chain of the Andes ; 

 and their ridge is every where covered with porphyritic for- 

 mations, basaltes, phonolites, and greenstone. But a cir- 

 cumstance peculiar to the equatorial mountains is the vast 

 height, to which the rocks of subsequent formation to gra- 

 nite ascend. This base is almost wholly covered by these 

 more recent formations, and the highest point at which 

 Mr. von H. observed it was 3500 met. [3825 yards]. The 

 summits of Chimborazo, Antisana, &c, at the height of 

 6372 met. [6964 yards], are of porphyry. Mr. von H. 

 likewise points out the different heights, at which the other 

 stratifications are met with. The remains of organic bodies 

 arc very rare in the mountains near the equator, as calca- 

 reous stones are by no means abundant. Some are found 

 however at the height of 4300 met. [4699 yards]. The 

 fossil bones of elephants, which Mr. von H. has collected, 

 were found about 3000 met. [3278* yards] only. 



The great masses of sulphur, that abound in the Cordil- Sulphur, 

 lera, are frequeutly met with in primitive rocks, at a dis- 

 tance from volcanoes. 



The greatest number of volcanoes are found in the chain Volcanoes, 

 of the Andes. There are more than fifty, between cape 

 Horn and mount St. Elias, that still emit flames. Some of 

 them pour out lava; others, as those of Quito, throw up 

 scorified rocks, water, and clay. 



The most recent volcano is that of Xorullo, or Jorullo, 

 [of which an account has already been given in p. 81 of this 

 volume]. The air collected at the bottom of the crater by 

 Messrs. von H. and Bonpland contained more than 0*05 of 

 carbonic acid. y 



The lowest limit of the snows under the equator is one of Limit of snoir. 

 the most constant of the natural phenomena. From the 

 various measures which he took Mr. von H. estimates it at 

 4795 met. [5240 yards]. The Cordillera of the Andes has 

 no glaciers, owing probably to the little snow, that falls 

 between the tropics; but at Chimborazo, on digging in the 

 earth, snow of very great antiquity is found. 



In his description of the animals that inhabit the Andes, 

 Mr. von II. notes the different heights, at which they are 

 seen. 



His 



