THEORY OF THE EARTH. 441 



influence. And if I consider this great deposit, with 

 its salt and gypsum, as constituting one of the greatest 

 blots in a Theory of the Earth, let it at least be de- 

 clared that we are in a state of utter ignorance ; though 

 let me repeat, that its wide extent, added to characters 

 so peculiar and so uniform, indicates some peculiar 

 condition in the earth, at, perhaps, the periods of 

 its formation and elevation both, which marks our 

 ignorance even more than the presence of these 

 minerals. 



If the lias denotes a marine deposition of ordinary 

 alluvia, accompanying the increase of marine animals, 

 the presence of terrestrial ones in certain portions of 

 it indicates nothing more than its superficial position 

 at these points ; proving also nothing respecting the 

 nature of that creation. But while the oolithe, or what- 

 ever analogous series may exist elsewhere, marks the 

 gradual increase of marine animals at least, its oolithic 

 portions possess a peculiar interest, connected with 

 those depressions which I have argued in the preceding 

 view of the Earth's conditions. These can only be 

 formed near the surface, or on sea shores, while, as 

 they are now vertically separated by solid calcareous 

 strata, it indicates the very changes of level in ques- 

 tion, during the progression of this great series ; and 

 thus tends to confirm these views ; as it also corrobo- 

 rates the former theory of the mode in which the suc- 

 cessions of coal beds have been produced. 



The absence of organic bodies and limestones from 

 large portions, at least, of the green sand, marks, as I 

 already said, the importance of the revolution pre- 

 ceding the deposition of this series. The subsidence of 

 the first lignite seems to have destroyed life, as that of 

 the inferior coal did ; and the results are seen in the 

 green sand, just as in the red inarl. How far this 



