250 DOMAIN XI. DECOMPOSED. 



anthus, may become rifty, and thus split by the 

 weather. 



Decayed Saussurite, from the Alps. 



The same, with amianthus, from the Pyrenees. 



NOME XIII. D. MARBLE. 



Argillaceous marble, as already mentioned, is 

 peculiarly subject to decomposition. In the 

 north of England, black marble has been ob- 

 served, accompanied with a soft grey substance 

 called rotten-stone; but this seems rather an 

 adherence than a decomposition. Rotten-stone, 

 though also used in polishing, must not be con- 

 founded with tripoli, which seems a mixture of 

 very fine clay and sand, and is only found in 

 veins. 



NOME XIV. D. ALABASTER. 



In particular circumstances, this substance 

 first becomes of a dull white, and then decom- 

 poses into dust. 



