DOMAIN VIII. 



DIAMICTONIC. 



General 

 observations. 



THESE rocks, in which the substances 

 may be said to be chemically combined, 

 form the most difficult province of the 

 whole science, and might deserve a sepa- 

 rate treatise, like the Cryptogamia of the 

 Botanists. Siderous earth, for example, 

 may be found so intimately and equally 

 combined with the siliceous, that the rock 



