( i6 ) 



tufa. In more than one place, in this work i 

 . I have fpoken of volcanic tufas, but almoft 

 always incidentally. The prefent fpecies of 

 this fubftance requires to be treated of fome- 

 what more at length. 



At the beginning of this work, when 

 fpeaking of the volcanic tufas of Pofilipo, 

 I faid, and endeavoured to prove, that 

 it was probable they were formed by 

 ilimy eruptions ; though I would not deny 

 that afhes, fand, and other fubtile matters 

 ejected by volcanos, and penetrated either 

 by the rain-waters or thofe of the fea when 

 they covered the bafes of the burning moun- 

 tains, have been confolidated into fome 

 tufas*. The tufa of Lipari, of which I now 

 fpeak, has every appearance of having been, 

 an earthy current. It begins at about a hun- 

 dred paces from the city, and continues, 

 without interruption, to beyond the fum- 

 mit of the Monte della Stufe, or Mountain 

 of the Stoves. This mountdn, like mofl 

 of the others, varies confiderably in its dif- 



» See Chap. II. 



ferent 



