19 



ton of the substances of which it undertakes to 

 treat. 



In attempting an accurate limitation of terms, 

 it must either accomplish that object imperfectly, 

 and thus increase the confusion of the present 

 nomenclature, or else introduce a cumbrous and 

 u n wieldj' catalogue. 



The facility of investigation professed to be 

 acquired by such an arrangement, is limited to 

 the mere knowledge of the specimen in the stu- 

 dent's hand : it affords him no assistance in dis- 

 criminating the accidental from the essential, 

 nor in tracing the rock and its connections from 

 a knowledge of the specimen. 



If it involves no hypothesis, it also rejects all 

 those known geological relations which have 

 been rescued from this censure. 



To which disadvantages it may also be added, 

 that it makes all rocks of equal importance, how- 

 ever rare or however accidental they may be. 



That it multiplies trifling and unimportant 

 distinctions. ^ 



That it renders geological description, either 

 c 2 



