( Jio ) 



from the knowledge we have of our cGm> 

 mon fire, how fuch a flone can be liquefied 

 and flow without lofmg one of its natural 

 lineaments. 



LaRly, the lavas with a piteh-flone bafe, 

 which are very abundant in thefe moun- 

 tains, are a third objed: deferving our 

 attention. It is not certain that Etna or 

 Vefuvius have ever thrown out a fingle 

 fragment of them : and the fame obferva- 

 tion may be made of the reft of the Phle- 

 grsean fields. In Lipari alone, among all 

 the Eolian iflands, I have found detached 

 and fcattered pieces, but which had rather 

 pafied into the ftate of enamel *. The 

 volcanic pitch-ftone is not peculiar to the 

 Euganean mountains : the volcanos of 

 Hungary and thofe of Auvergne furnifh 

 fome noble fpecimens .of it. It remains, 

 however, to enquire whether it is to be 

 clafled among the lavas, or rather whether 

 it has ever formed currents. We may be. 



* See Chap. XVII. 



fatlsfied 



