198 M. Von Bucb on Volcanos and Craters of Elevation. 



elevation of the Somma. The included masses must therefore 

 have been in this district before the Somma, and much less Ve- 

 suvius, existed. They therefore cannot be ejected masses of 

 Vesuvius, or even of the Somma. Most probably they are the 

 products of a submarine deeply-seated volcanic action ; and as 

 an argument in favour of this opinion, we have the great analogy 

 which subsists between the substances now under consideration, 

 and the crystals which have been produced by the action of pri- 

 mitive rocks, that have been sent from beneath, on limestone, 

 and the contact edges of both rocks, as for example at Monte 

 Monzoni, in the valley of Fassa, in the valley of Ala in Pied- 

 mont, and also at Arendal in Norway. At all these localities a 

 great many of the Vesuvian minerals occur, and in part of equal 

 beauty, viz. vesuvians, garnets, epidote, unattached crystals of 

 augite, and others. It is only numerous species of the zeolite 

 family that are peculiar to Vesuvius. These have been formed 

 at a later period than the first mentioned minerals, and it would 

 seem under very different circumstances ; meionite, nepheline, 

 and sodalite, frequently cover vesuvian, crystals of hornblende, 

 and garnets, but are never covered or enveloped by these mi- 

 nerals. 



Should appearances so varied and so intimately connected to- 

 gether not be sufficient to prove the elevation of the Somma 

 through the strata of tuffa, and the elevation of Vesuvius in the 

 middle of the crater of the Somma, still more decided evidence 

 is to be found in the neighbourhood of Naples, a district so rich 

 in important volcanic phenomena ; evidence which seems to place 

 the question beyond all doubt. Thus the elevation of such strata 

 of tuffa with a crater actually occurred before our eyes. The 

 Monte Nuovo near Pozzuoli, formed on the 19th September 

 1538, is a true crater of elevation, and by no means an erupted 

 hill. The disintegrated strata of tuffa in the middle, and the 

 blocks, ashes, and dust scattered around by the gases of the 

 interior, by which Pozzuoli itself was nearly entirely buried, 

 and every thing involved in darkness ; might well lead the con- 

 temporaneous observers to the conclusion that the mountain itself 

 had been produced by these ejected masses; and so much the 

 more, because its surface was seen covered by them. But the 

 aspect of the crater teaches us quite a different view of the sub- 



