580 



GEOGRAPHICAL BOUNDARIES 



[Ch. XXIII. 



the equator, and continuing for about 1 30 miles north of it, 

 when there occurs another undisturbed interval of more than 

 six degrees of latitude, after which we arrive at the volcanos 

 of Guatemala or Central America, north of the Isthmus of 



Panama.* 



Having thus traced out the line from south to north, I may 



first state, in regard to the numerous vents of Chili, that the 



volcanos of Yantales and Osorno were in eruption during the 



great earthquake of 1835, at the same moment that the land 



was shaken in Chiloe, and in some parts of the Chilian coast 



permanently upheaved ; whilst at Juan Fernandez, at the dis- 



eruption took place beneath the sea 



miles from 



We 



thus 



an eruption took piaue ucucauu ^^ »^. ..- — ~ 



proofs of a great subterranean disturbance extending simul- 



miles 



and south, and in one part at least 600 due east and west (see 



XXVIII 



Some 



summit 



height, as that of Antuco, in lat. 37 



which is at least 16,000 feet above the sea. From the flanks 



immense 



have issued, one of which flowed in the year 1828. This 

 event is said to be an exception to the general rule ; few vol- 



Quito 



modern 



ving merely 



ejected vapour or scoriae. 



Both the basaltic (or augitic) lavas, and those of the fel- 

 spathic class, occur in Chili and other parts of the Andes ; 

 but the volcanic rocks of the felspathic family are said by 

 Yon Buch to be generally not trachyte, but a rock which has 



mixture 



The 



mentioned 



found in common felspar. 



The volcano of Eancagua, lat. 84° 15' S., is said to be 

 always throwing out ashes and vapours like ' Stromboh, a 

 proof of the permanently heated state of certain parts of the 

 interior of the earth below. A year rarely passes in Chili 

 without some slight shocks of earthquakes, and in certain 



Buch's Description of valuable sketch of tie principal volcanos 



Canary Islands (Paris, ed. 1836) for a 



* See Von 



of the globe. 





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