584 



GEOGRAPHICAL BOUNDARIES 



[Ch. XXIII. 



* 



periods from the volcanos of Auvergne, now extinct, we find 

 the bones and skeletons of lost species of quadrupeds. 



Mexico. — The great volcanic chain, after having thus pur- 

 sued its course for several thousand miles from south to 

 north, sends off a branch in a new direction in Mexico, in 

 the parallel of the city of that name, and is prolonged in a 

 great platform, between the eighteenth and twenty-second 

 degrees of north latitude. Five active volcanos traverse 

 Mexico from west to east — Tuxtla, Orizaba, Popocatepetl, 

 Jorullo, and Colima. Jorullo, which is in the centre of the 



t? 



platform 



miles from 



ocean — an important circumstance, as showing that the 

 proximity of the sea is not a necessary condition, although 

 certainly a very general characteristic, of the position of 

 active volcanos. The extraordinarv eruntion of this 



moun 



tain, in 1759, will be described in the sequel. If the line 

 which connects these five vents be prolonged in a westerly 

 direction, it cuts the volcanic group of islands called the 

 Isles of Revillagigedo. 



To the north of Mexico there are said to be three, or ac- 

 cording to some, five volcanos in the peninsula of California; 

 and a volcano is reported to have been in eruption in the 



JNT.W. coast of America, near the Colombia River, lat. 



45° 37' N. 



West Indies. 



Quito 



inclines to the belief, that if we were better acquainted with 

 the region to the east of the Madalena, and with New Gra- 

 nada and the Caraccas, we might find the volcanic chain of 

 the Andes to be connected with that of the West Indian, or 

 Caribbee Islands. The truth of this conjecture has almost 

 been set at rest by the eruption, in 1848, of the volcano of 

 Zamba in New Granada, at the 

 lena.* 



Of the West Indian Islands there are two parallel series, 

 the one to the west, which are all volcanic, and which rise 

 to the height of several thousand feet ; the other to the east, 

 for the most part composed of calcareous rocks, and very 



mouth of the river Mada 



* Comptes Eendus, 1849, vol. xxix. p. 531 



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