No. III. — Pausilipo and the Lago cCAgnano. S51 



magnitudes, and bearings. To gain a true idea of the ar- 

 rangements of this wonderful district, nothing can be more 

 proper than a visit to the Camaldoli : from it we have a 

 view of at least fifty miles in one direction only, that of Ter- 

 racina. In constitution, the ground over which we pass to 

 this convent, resembles much the upper strata of the hill of 

 Pausilipo, and is particularly pumiceous, the beds varying in 

 colour, but little in composition, and invariably friable and 

 harsh to the feel, showing few of the characters of the tufa, 

 which probably constitutes a great part of its mass, as it does 

 of that part of the ridge with which it is connected, and indeed, 

 it is seen to alternate with the pumiceous strata ; and the lat- 

 ter are found divided by others, in which clay and sand are 

 mixed with the pumice. Indeed, I have remarked in my me- 

 moranda of this interesting excursion, that part of the beds 

 resemble so strongly simple formations of alkivium, that, to an 

 unpractised eye, it requires the sense of touch to prove that the 

 materials are harsh volcanic cinders, which so remarkably as- 

 sume the characters of alluvial deposits. This marks unequi- 

 vocally the true origin of these tufaceous mountains ; and it 

 may be proper here to say a word or two on the subject, 

 though some time hence, when treating of the theoretical con- 

 clusions to be drawn from the physical appearances of the Bay 

 of Naples, we shall have an opportunity of considering it with 

 more connection. 



Enough has been already said in this and my last paper, to 

 show how much facts tend to prove, in the vicinity of Naples, 

 that the volcanic agency has been combined in these formations 

 with all the peculiarity of subaqueous deposits. Indeed this is 

 one of the very few points on which geologists are pretty 

 generally agreed, and Nature has seldom written the history 

 of her revolutions in former ages in more legible characters. 

 When I first viewed these formations myself, and endeavour- 

 ed, though with the eye of a novice, to compare them with 

 those in the Campagna di Roma, before I was initiated into 

 the doctrines of more profound observers who had preceded 

 me, by a separate track I gained the same general conclusions, 

 and saw spread before me in the fields of volcanic fire, proofs 

 that nature had performed these great acts of creative energy 



