270 Geological Gleanings. 



" The alleged parallelism and uniformity of thickness in the 

 volcanic beds of the Val del Bove, when traced over wide areas, 

 is next considered, and the author remarks that neither in the 

 northern nor southern escarpments of the great valley, could he 

 and his companion verify the existence of such parallelism. Ex- 

 ample of a marked deviation from it are given, both in cliffs seen 

 from a distance, and in others which were closely inspected, even 

 in cases where these last, when viewed from far off, appeared to 

 contain regular and parallel strata. 



"The direction and position of the dikes in the Val del Bove is 

 then spoken of, both in reference to the two ancient centres of 

 eruption, and to the question of the altered inclination of the inter- 

 sected beds. In regard to the arrangement also of tbe lateral 

 cones of eruption, the question is entertained, whether they are 

 disposed in linear zones, or are in some degree independent of the 

 great centre of Mongibello. 



" The origin of the Val del Bove has been variously ascribed 

 to engulfment, explosion, and aqueous erosion. Admitting the 

 probable influence of the two first causes, the author calls attention 

 to the positive evidence in favour of aqueous denudation afforded 

 by the accumulation of alluvium in the low country at tbe eastern 

 base of Etna between the Val del Bove and the sea. This rudely 

 stratified deposit, 150 feet thick and several miles in length and 

 breadth, contains at Giarre, Mangano, Riposto and other places, 

 fragments, both rounded and angular, of all the rocks, ancient and 

 modern occurring in the escarpments of the Val del Bove, and it 

 implies the continuance there for ages of powerful aqueous erosion. 

 The alluvium of Giarre is therefore supposed to bear the same re- 

 lation to the Val del Bove that the conglomerate of the Barranco 

 de las Angustias bears to the Caldera of Palma in the Canaries ; 

 and those two craterlike valleys, as well as the Curral of Madeira, 

 are believed to have been shaped out in great part by running 

 water. But to render this possible, the suspension, for a long 

 period, of the outpouring of lava on the eastern flank of Etna must 

 be assumed." 



" The author fully coincides in the generally received opinion 

 that the accessible parts of Etna are of subaerial origin, and refers 

 to some fossil leaves presented to him by MM. Gravina and 

 Tornabene of Catania, as well as to others collected by himself in 

 situ, from the volcanic tuffs of Fasano and Licatia, which have 

 been determined by Prof. Heer to belong to terrestrial plants, of 



