268 



CHAP. XIV. 



On the particular Order of Succession among Rocks. 







IT had been so often and so confidently said that 

 a definite and constant order of succession existed 

 throughout all rocks, that it had passed into an axiom 

 in geology. Time has not yet dissipated this phantom, 

 though it is gradually fading from among the 

 realities in which the science abounds. As there are 

 few among the dogmas of geologists which have more 

 contributed to impede the progress of investigation, 

 it will be useful to examine the grounds on which it 

 still holds its place. The first step in forming a firm 

 foundation is to remove the tottering materials of the 

 old one. 



As the doctrine of universal formations is in a great 

 measure implicated in this hypothesis, the same ex- 

 amination will serve to try the truth of both. Such 

 also are the catenations of hypotheses, that I must 

 equally notice that branch of the same theory, which 

 asserts that the successive rocks are found to terminate 

 at lower levels above the mean surface of the earth, 

 in an order corresponding to that of their superposition 

 or formation. 



As also it is held to be unfair to examine part of a 

 theory separated from its connexions with the re- 

 mainder, it must be remembered that in this one it is 

 asserted that no extensive denudations of the surface 

 have taken place, particularly in antient times. 



In strictness of meaning, the term universal forma- 



