MINER A LOGICAL QUERIES. 125 



with greenstone-slate, and hence is to be consider- 

 ed as of primitive formation \ but the fullers-earth 

 of England, is evidently a flcetz formation, and 

 appears to occur in beds, in a particular kind of 

 sandstone which forms the fundamental rock of 

 the chalk formation f. This is all we know of the 

 English fullers-earth, — a proof how much remains 

 to be done before we can consider our knowledge 

 of its geognostic relations as complete and satisfac- 

 tory. 



14. Does the limestone of Derbyshire, belong 

 to the transition class ? 



* Aitken's " Dictionary of Chemistry/' article Ful- 

 lers-earth. 



