OF THE EARTH. 641 



glomerates do, although they are valuable records of 

 time, as formerly remarked: and that this cannot he 

 proved, I have shown in the preceding chapter. But there 

 is one case in which the evidence afforded hy organic 

 fossils is peculiarly valuable. It is that of the coal 

 strata; in which, the presence of terrestrial bodies 

 proves the production, above the level of the sea, of 

 strata which, but for that evidence, we might have 

 supposed to have been formed below it. The full 

 value of this fact will appear when these strata shall 

 hereafter be examined. 



In proceeding to enquire into the number of the 

 revolutions of the surface of the globe which appeal- 

 capable of proof from the evidence thus indicated, I 

 must remark, that it will depend on considerations of 

 other kinds, what the extent of these has been ; how 

 far they may be considered local, or general, or uni- 

 versal. It is also scarcely within the limits of our 

 means, to enquire into the lengths of the intervals of 

 repose between successive revolutions ; since the evi- 

 dence on which this ought to rest is of a very imper- 

 fect nature, from the numerous accessary circum- 

 stances by which it may be vitiated: though the little 

 which may be fairly offered in the way of rational 

 conjecture, will be stated. And the reader is now- 

 prepared to understand the causes of these revolutions ; 

 as they have already been examined in treating of those 

 elevations of strata which offer the most convincing 

 proofs of them. 



There was a time when Geologists expected that 

 every enquiry respecting the structure of the earth 

 should contain an investigation of its origin and crea- 

 tion. That period, it must be hoped, is past. If 

 there are any who are still desirous to commence their 

 researches from periods which lie beyond the scope of 



