M. L. Elie de Beau mount on the Structure and 



face. Such a soulevement would even render it much more easy 

 to understand a subsequent " eboulcment" 



The question thus presents itself, Whether the masses which 

 form the circuit of the Val del Bove occur at the present day in 

 their original position, or if they do not owe to a soulevement 

 subsequent to their formation, the outline which elevates them 

 above the whole neighbouring country ? I have been led to de- 

 cide this question in favour of the hypothesis of the " souleve- 

 ment" by six considerations, nearly independent of one another : 

 viz. l.v^, By the consideration of those veins which rise to the 

 upper part of the escarpments of the Val del Bove ; for, if the 

 fissures which have given rise to these veins took place across a 

 mass of such magnitude as the nucleus of the gibbosity of Etna 

 of the present day, the melted matter could not have filled them 

 to the top. ^d, By the consideration of the thickness of the layers 

 which have been formed by the melted matter poured out from 

 the openings of the veins ; for a mass of melted matter flowing 

 from the lower extremity of a fissure on a plane so highly in- 

 clined as some of the layers are at present, could only have 

 formed a narrow current. 3c?, By the consideration that the 

 volcanic products given out by the openings of the veins are 

 equally distributed on the two sides of the opening, whereas on 

 an inclined surface they could only be spread over the side to- 

 wards which the slope was directed, ^th, By the consideration 

 of the invariably insignificant thickness of the layers of loose 

 matter, which, if they had been received on a surface inclined 

 under an angle of 27% for example, would have slipt down, and 

 have been accumulated at the base of the declivity to a consi- 

 derable thickness, and thus have given rise to a rectilinear talus 

 5th^ By the consideration of the uniformity of the thickness pre- 

 sented by the layers of melted matter, even in the places where 

 they are undulated ; a fact quite contrary to the phenomena ob- 

 served in modern lavas, which, when they stop on an undulating 

 surface, present alternate enlargements and contractions. Finally, 

 I am anew led to the same conclusion by a Qth oi'der of consi- 

 derations, which seems to me still more conclusive, and in re- 

 gard to which it is necessary for me to enter a little into detail 



The uniformity which I have particularly specified as charac- 

 terizing the layers of melted matter in the Val del Bove is not 



