42 



ETNA. 



[Ch. XXVI. 



must 



from a vessel at sea off Aci Castello, to get a view of the V 1 

 del Bove througli the opening. This notch is a section of ^a 

 ravine of denudation once continuous with the Yalle d ^ 

 Tripodo, which furrowed the old cone before the Val del 

 Bove was formed. 



The second valley, called ' dei Zappini,' runs parallel to the 

 former, and is similar in its geological features though less 

 grand. The torrents that drain both of them are swallowed 

 up at their louver end in the holes and grottoes of the great 

 lava current of 1792, which, flowing down from a different 

 and higher part of Etna, crossed the channels of these 

 torrents and blocked up the ravines in which they flow. 



The third valley, that of Calanna before alluded to, is the 

 most interesting because at its upper end we find the preci- 

 pice before described, figs. 85 and 86, p. 34, over which the 



lavas of 1819 and 1852 have cascaded. There can 

 be no doubt that this precipice, the Salto della Giumenta, was 

 the site of a waterfall when a river flowed down from the 

 ancient cone, before the origin of the Val del Bove. The 

 space between the hills of Zoccolaro and Calanna indicates 

 the place of the upper valley, while the Salto was formed by 

 the river cutting its way backwards after the manner of the 

 stream in the Cava Grande before described, p. 35, or of the 



modern 



Ma 



compare 



If Vesuvius continues to be as active as it has been for the 

 last eighteen centuries, its lavas may one day top the crest 

 of the Atrio and cascade over the precipices at the head of 

 the Casa del' Acqua and the Fosso di Cancharoni, in the same 

 way as the Etnean st 



down the Salto della Giumenta. 



earns 



^f the cone of Et 



emai 



1. p. 91) that confined notions in regard to the quantity of 



more 



to retard the progress of sound theoretical views in geology; 

 the inadequacy of our conceptions of the earth's antiquity 

 havmg cramped the freedom of our speculations in this 



Cf' 



i^ 



( 





p 



e 



jten 



1)01111 



<j 









ffi 



itbii 



much in the same 



views 



Ifl 

 erupt 



volca 



an ex 



aver! 



of s 

 tlie 



con 



acti( 

 sions 

 serei 



betm 

 ofth, 



mend 

 ando 

 rise a 

 aiieiei 

 Bore. 



exalts 

 of i-eji 



If. 



W t, 



