CLASSIFICATION OF ROCKS. // 



triumphant, compared with even the last and most fa- 

 shionable arrangements of Zoology. Imperfect as any 

 arrangement may be, its uses are still apparent; and 

 were it no more, it might stand, like a Code in Legis- 

 lation, as a beacon to direct what time and knowledge 

 may hereafter demand. If I am not satisfied with the 

 following attempt, I have caused it to coincide with 

 the antient binary one, so as to allow of its use as a 

 mere improvement of that; and if I have only num- 

 bered the new classes, merely suggesting an ordinal 

 Greek term to those who love Greek just as they least 

 understand it, it is, that to make names before we are 

 sure of the things, is not the most prudent policy. 

 A few further remarks on this table will complete 

 what the reader might not observe for himself. I 

 have already* given reasons for repeating the same 

 rocks in more classes than one, and for distinguishing 

 the porphyries and traps into at least two classes. In 

 the fifth class, I have only given the principal varieties: 

 a fuller list, derived from the English .strata, would 

 be topographical ; while did I distinguish minutely 

 in the later rocks, I must have adopted the same pro- 

 ceeding as to the endless varieties of gneiss and others 

 in the primary class. The strata thus named are not 

 given as if in the order of nature, because I have 

 already shown that there is no such order : and, in the 

 secondary class, the order of England, if that be ex- 

 pected, is but an order among varieties. If I would 

 gladly have extended the few minute commentaries 

 given in the table, it was incompatible with that form. 

 I have only to add, that if my plan does not allow me 

 to follow it in the subsequent descriptions of rocks, 

 so have I been obliged to refer, for their details, to 

 that work on their Classification which is the grammar 

 of the present one, and of the science. 



