Origin of Mount Etna, S81f 



transversely by an immense number of veins of lava, sometimes 

 vertical, sometimes more or less oblique, which, less crumbling 

 than the beds, sometimes project beyond the escarpments like 

 remains of gigantic walls. These veins arc old fissures, analogous 

 to the meridional rents of Etna, that have been filled by ancient 

 lavas, and through which the melted volcanic matter, now dis- 

 posed in regular layers, would seem to have issued. But notwith- 

 standing this analogy, it must be remarked that these veins have 

 a general tendency to an E.N.E. direction, which shews that the 

 fractures which they have filled were not meridional fractures, 

 standing in connexion with a central axis, and that at the eptx.'h 

 of the outflowing of the lava, the eruptions had not, as at tJie 

 present day, a fixed and determinate centre. 



The rock being cut so sharply in the escarpments of tlie Val 

 del Bovc, it is incontestable that this vast circus owes its exist- 

 ence to the removal of an enormous mass of matter which for- 

 merly occupied the space, or at least a great part of it. Profes- 

 sor Buckland, Mr Lyell, and M. de Buch have successively 

 formed the idea that the matter now wanting must have been 

 ingulfed in the interior of the mountain, an opinion which seems 

 to me the most probable that can be advanced. This inguli'ment 

 may have been comparable to the falling in of the volcano of 

 Papandayang, in the Island of Java, and to that of the cones of 

 Carquairazo, and of Capac-urca, in the Andes of Quito. But as 

 the lava does not rise to the external surface either in the voJ- 

 canos of Java or of Quito, we have abundant latitude for con- 

 ceiving that there are empty spaces in their interior ; while if 

 cavities exist under Etna, they must be filled by lava, at least 

 during the period of eruptions, for the lava is then elevated even 

 to the summit. The surface that the ancient lavas have covered 

 was in this respect in the same condition as modern Etna, for the 

 lava flowed to the surface by fissures, which were produced at 

 Certain intervals. We might in fact say that the ingulfment 

 would take place in a cavity which the lava filled and abandon- 

 ed alternately. But if tlie lava could issue from that cavity, 

 could re-enter, and be submitted to a pressure capable of making 

 it mount by the fissures to the external surface, there seems no- 

 thing impossible in believing that it may have upraised that sur- 



