Ch. VII.] VAL DEL BOVE. 87 



Fal del Bove. After passing up through the defile, called 

 the e Rocca di Calanna,' we enter a third valley of truly 

 magnificent dimensions the Val del Bove a vast amphi- 

 theatre four or five miles in diameter,, surrounded by nearly 

 vertical precipices, varying from one thousand to above three 

 thousand feet in height, the loftiest being at the upper end, 

 and the height gradually diminishing on both sides. The 

 feature which first strikes the geologist as distinguishing this 

 valley from those before mentioned, is the prodigious mul- 

 titudes of vertical dikes, which are seen in all directions tra- 

 versing the volcanic beds. The circular form of this great 

 chasm, and the occurrence of these countless dikes, amounting 

 perhaps to several thousands in number, so forcibly recalled 

 to my mind the phenomena of the Atrio del Cavallo, on 

 Vesuvius, that I imagined once more that I had entered a 

 vast crater, on a scale as far exceeding that of Somma, as Etna 

 surpasses Vesuvius in magnitude. 



But having already been deceived in regard to the crescent- 

 shaped precipice of the valley of Calanna, I began attentively 

 to explore the different sides of the great amphitheatre, in order 

 to satisfy myself whether the semicircular wall of the Val del 

 Bove had ever formed the boundary of a crater, and whether 

 the beds had the same quaqua-versal dip which is so beauti- 

 fully exhibited in the escarpment of Somma. If the supposed 

 analogy between Somma and the Val del Bove should hold true, 

 the tuffs and lavas, at the head of the valley, would dip to the 

 west, those on the north side towards the north, and those on 

 the southern side to the south. But such I did not find to be 

 the inclination of the beds ; they all dip towards the sea, or 

 nearly east, as was before seen to be the case in the Valley of 

 Calanna. 



There are undoubtedly exceptions to this general rule, which 

 might deceive a geologist who was strongly prepossessed with 

 a belief that he had discovered the hollow of an ancient crater. 

 It is evident that, wherever lateral cones are intersected in the 

 precipices, a series of tuffs and lavas, very similar to those which 



