C 288 ) 



fioned by the micas of that colour which 

 have remained, ina greatmeafure, refradory. 



I fhall omit to defcribe another porous 

 lava, Hkewife from Rua ; and two of the 

 compact Ipecies, with a horn-ftone bafe, 

 found in that vicinity. I think more de- 

 ferving of attention one difpofed in ftrata 

 obhque to the horizon, which is found on 

 the fides of the road leading from Galzig- 

 nano to Ciefa. 



This lava'is white, and has the compa£l- 

 nefs of fine carbonates of lime, which it re~ 

 fembles in appearance, fracture, and weight. 

 It affords a few fparks with fteel, and is 

 dul:inguiihed from other lavas by numerous 

 points of a delicate green, fcattered over the 

 white ground ; but which, to be viewed 

 diflinctly, require a lens with a ftrong light. 

 When thus magnified, v\^e find that they are 

 a femi-pulverous earth, which may be de- 

 tached with the point of a needle, and is 

 placed between the fiffures of minute amor- 

 phous maiTes of fhining, white, and ex- 

 tremely 



