( 42 ) 



The fpacious and deep excavations made 

 in the tufa by the rain-water, and which 

 extend from the bottom of the mountain 

 to the fummit, afforded me an opportunity 

 to difcover and examine the ftony fub- 

 ftances I have defcribed ; for it was only in 

 thofe excavations that they were vifible : in 

 every other part nothing appeared but the 

 naked fuperficial cruft of the tufa. None 

 of thefe fubftances are dlfpofed in currents; 

 they are all detached ; and thus render it 

 probable that they fell into the tufa after 

 having been thrown up into the air in vol- 

 canic ejedions. 



When "we have reached the fummit of 

 the mountain, an ample plain opens, formed 

 of the fame tufa, but become earthy, in 

 which corn is fown, and a few vineyards 

 are planted. Here we find numerous 

 pieces of a fhining glafs, which is femi- 

 tranfparent, of a blackilh colour, and fome 

 of the fineft and pureft to be found in Li- 

 pari. As I wiflied to difcover the origin of 

 this fubiUnce, 1 caufed the place where it is 



founcj 



