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PRELIMINARY REMARKS ON THE NATURE AND 

 CHARACTERS OF THE PRIMARY CLASS. 



IN the name of this class, is implied the essential 

 character on which it is founded. The rocks that 

 are included in it, are so arranged, from an opi- 

 nion that they were formed previously to the de- 

 position of those which are ranked in the secon- 

 dary class. That opinion is founded on the fact, 

 that wherever the rocks of the latter division 

 occur in company with the former, they are al- 

 ways superior in geological position; and that, 

 in no case, a member of the primary class is found 

 intruding among those of the secondary. 



If, in all instances where rocks occur in na- 

 ture, both classes were to be found together, or a 

 regular sequence could be inferred by the com- 

 parison of positions, there would exist no diffi- 

 culty in distinguishing the two, in every case, by 

 their geological situations; it being here pre- 

 sumed that their common line of separation is 



