CLASSIFICATION OF ROCKS. 73 



initive class, they are necessarily placed at high angles, 

 and, in the secondary, at low ones, or horizontally. In 

 both, they are found at every possible angle ; and I 

 trust that I need not quote evidences, when horizontal 

 gneiss and vertical chalk must be known to every 

 geologist, in addition to thousands of cases more. 

 Again, when it is said that a consecutive order, or 

 common parallelism, exists in each class, this, which 

 may be true of the primitive, is not so of the second- 

 ary, as I have fully shown ; while I need not recur 

 either to the facts or the theory, in this case, which 

 prove that such a secondary class is not a natural one. 

 The whole arrangement therefore is artificial ; though, 

 if the main defects lie in the secondary class, as far as 

 the strata are concerned, it evidently confounds, in 

 both, every thing respecting the unstratified rocks, 

 which, in reality, it had not distinguished : while its 

 modern followers either forget this most important 

 circumstance, or persist in preferring a geological 

 Pope to all evidence. But, even as artificial, it is de- 

 fective by not distinguishing these, and further, by 

 forgetting the tertiary deposits ; not to mention also 

 the alluvial and the volcanic substances. It remains to 

 attempt a new classification ; while this criticism, de- 

 manded by the state of the science and of the prac- 

 tice, will also have tended to explain the grounds on 

 which it is recommended. The emendation of this 

 antient division, which I adopted in the Classification 

 of rocks, did nothing more than separate the unstrati- 

 fied ones ; while I even adopted appendices for what I 

 did not then choose to touch. Proposing, now, that 

 still imperfect one, which is all that I know how to 

 invent at present, I must premise a few remarks. 



I need not repeat that a Natural classification is the 

 only worthy object of pursuit, while it is, unfortu- 



