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tone, rudely formed, it is true, but very 

 diftinguifliable. They confift of a lava of 

 a cinereous grey colour, of a perroGliceous 

 bafe, and marked, in many parts, witii thin 

 reddifli flreaks parallel to each other. A 

 confiderable number of rhomboidal, iliin- 

 ing, and tranfparent fel tfpars, and a few 

 black, hexagonal particles of mica are con- 

 tained in the bafe of this lava, which 

 changes in the furnace into a dark grey en- * 

 am>el, with the fufion of the feltfpars and 

 the micas. In feveral parts of the moun- 

 tain, when we dig into it, we find imper- 

 fect prifins ; and they frequently proje«£t 

 out near tlie fumniit, and on tie fides ; as 

 we may obferve in the road leading to 

 Praglia. The mountain U formed of this 

 lava, which, on the furface, is decompofed 

 and become earth, in which a number of 

 olive-trees grow and thrive. A fimilar de- 

 compoiitlon is obfervable at Monte Roflb, 

 the earth of which is, in a great meafure, 

 a mixture of fragments of micas, feltfpars, 

 and flioerls. 



The 



