170 



SERPENTINE, 



Mineralogical writers have enumerated this 

 in their catalogues of minerals, but it is only 

 known as forming simple masses of rock. It 



does not enter into mixed rocks unless with 



/ 



limestone: supposing the conglomerates to be ex- 

 cluded from this term. 



STEATITE 



Is not a common ingredient, and is nearly 

 limited to serpentine and limestone. In granite 

 it rather seems accidental than essential. 



NOBLE SERPENTINE 



Occurs in similar situations with the former ; 

 to which it is very nearly allied. 



GYPSUM. 



This is found only in Gypsum, which has been 

 here enumerated among the rocks. 



IRON, 



This metal deserves to be enumerated among 

 the constituents of rocks, on account of the quan- 

 tity in which it sometimes enters into their com- 



