246 SECONDARY LIMESTONES. 



The groups which I have thus described in conformity 

 to custom, quite as minutely as I think necessary, have 

 been formed under presumptions rather than evidence, 

 and further, being local, have been generalized into 

 models or types for all the earth ; while they have also 

 been made deceptive, by adopting a single term for a 

 very compound series, and taking also a single member 

 for that term. If any of the presumed groups is a real 

 one, that must be determined by some definite condi- 

 tion of the earth under which it was formed, not 

 under the hypothesis of a nation or a sect: and, of 

 the true evidence and its value I shall soon enquire, 

 that I may prove, if possible, what geologists have 

 hitherto assumed, and at least separate evidence from 

 hypothesis. 



As to the extension of these groups, the red marl 

 is the only one yet proved to be widely spread over 

 the earth : arid when one nation infers identities, and 

 another disputes them in favour of its own, philoso- 

 phical geology turns a deaf ear to both ; having shown 

 that the Causes will not thus submit to dictation, and 

 must not be, as they ever have been, forgotten. I 

 have shown that the series in the primary rocks will 

 admit of no such generalizations, of either nature ; and, 

 since the secondary have been produced in a similar 

 manner, the same diversity must hold, in both re- 

 spects. Did I act respecting the primary strata of 

 Scotland as Geologists do about the secondary ones 

 of England, I should maintain them as the patterns 

 for the world : yet they who can now perhaps see the 

 one folly, can as little discern the other, as the Wer- 

 nerian school was unable to discover the equal fiction 

 of its Universal formations. The hypothesis is the 

 same for both ; but that is not yet seen, though it is 

 fully time that it should ; since it is not Geology, 



