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Thus we have a prodigious number of 

 foffil produ6lions which have the moft fpe- 

 cious appearances of lavas, and vitreous 

 lavas, though they have never fuffered li- 

 quefaction ; as is incontrovertibly proved 

 by the pieces, which, when they come out 

 of the furnace, retain exactly the configu- 

 ration they had before they were expofed 

 to the tire. 



Inftrudted by thefe fa£ls, I confefs that 

 the firll: time I faw the Euganean moun- 

 tains, and found myfelf in a theatre very 

 different from that prefented by the Eolian 

 ifles, not to mention Etna and Vefuvius, I 

 could not avoid entertaining doubts whether 

 the numerous foeks, which in a great part 

 form thefe mountains, owed their origin to 

 volcanic eruptions, or were pre-exiflent to 

 the fubterranean conflagrations, that had 

 only penetrated them, infixing in them in- 

 delible traces of their adion, but ftill leav- 

 ing them in the place where we at prefect 

 fee them. Every doubt however was re- 

 moved, and I remained convinced that 



thefe 



