( I? ) 



ferent parts, in one place prefentlng gentle 

 declivities, and in another fteep and rugged 

 defcents ; here plains nearly level, and there 

 precipices almoft perpendicular. The tufa 

 with which it is covered, takes exad:ly the 

 fame courfe ; and fometimes curves, and, as 

 it were, waves on the furface : nor does it 

 in the lead differ in its finuofities and wind- 

 ings, from the moft completely chara([le- 

 rifed currents of lava, which it likewife re- 

 fembles by being difpofed in beds lying one 

 over the other, as appears in thofe places 

 which have been moft corroded by the rain. 

 I therefore was of opinion, that this tufa 

 had been a ftream, if I may ufe the ex- 

 preffion, of flimy fubftances, that had flow- 

 ed down the mountain ; as examples are 

 not wanting of fimilar eruptions, produced 

 in the humid way, in the mountains Vefu- 

 vius, Etna, and Hecla. 



But here a difficulty prefented itfelf in 

 oppofuion to this hypothecs. Had this 

 part of the mountain been inundated by a 

 torrent of water ifluing from the earth, 



VOL. III. C when 



