ITALY. LETTER XT. 125 



But now arifes another queftion, Whether the 

 volcanos be produced in calcareous beds or under 

 ground of them ? 



Though 1 cannot decide it, I have very good 

 reafons to believe, that the limeftone of the Apen- 

 nines, in thefe fouthern parts of Italy, is fuper- 

 incumbent to argillaceous flate, as well as in the 

 Northern ones, which have been taken notice of 

 in my former letters. As I happened lately to 

 travel to Salerno *, I faw it plainly appear from 

 under the limeftone, and rife above ground clofe 

 to the road near the gates of that place. Mr. 

 Guettard, who accompanied me, can acted it ; and 

 his evidence will be the more valuable, as before 

 he had many times objected my opinion. There- 

 fore I am inclined to believe, that, according to 

 what has been obferved in the old Vicentine and 

 Veronefe volcanos, the deeped fire-places of thefe 

 in the Southern part of Italy are not in the lime- 

 ftone but in the flate, if not in a greater depth. 

 There are perhaps in the flate pyriticeous veins, to 

 whofe inflammation the fubterraneous fire might 

 be owing ; but I want evidences for it, as well 

 as for many other fuppofitions. 



' >ni ii 



* Behind the Carmelite convent, at SaUrr.o, is a place 

 in the ground, which exhales fuffocating damps (meffette). 



The 



