280 ON THE PARTICULAR ORDER OF 



we must not establish this as a canon in the science ; 

 because, a priori, there appears no chemical or phy- 

 sical reason why it ought to be so. To lay down 

 such laws, is to throw obstructions in the way of our 

 own progress, to fabricate a science instead of de- 

 ducing one. To do less, by making rules which 

 apply only to the cases whence they are derived, is to 

 do nothing ; it is to client ourselves with the shadow 

 of a science. 



It is not indeed very easy to see what purpose is to 

 be attained by this generalization, if the doctrine of 

 universal formations is abandoned. It is the basis 

 and support of that doctrine, if not the very thing 

 itself. Nor is it probable that, on general principles, 

 there can be a definite order of succession among the 

 greater series over extensive tracts of the globe, any 

 more than among the smaller beds in a limited spot. 



It is easy enough to understand how, in one de- 

 posit, a constant order, at least as far as relates ta 

 the principal strata, should have been preserved. It 

 is equally easy to admit, that confusion may have 

 been produced among the less important, merely by 

 the omission of a few out of a great number of alter- 

 nating strata of different kinds, without affecting the 

 general integrity and order of the deposit. But till 

 further reasons are produced to show that these de- 

 posits are universal, it will be impossible to admit, 

 that wherever rocks occur of similar characters in 

 distant parts of the world, they must necessarily 

 maintain the same order. Further, till they are 

 shown to be of much greater continuous extent than 

 is now probable, it can excite no surprise if, even in 

 Europe, that order of succession should differ. The 

 existence of tertiary deposits, proves that particular 

 collections of strata are limited; and it would be no 



