Ch. IX.] 



OF AQUEOUS ROCKS. 



99 



Groups of Fossiliferous Strata observed in Western Europe, arranged 

 in ivhat is termed a descending Series, or beginning' with the newest. 

 (See a more detailed Tabular view, pp. 101-106.) 



1. Post-Tertiary, including 



Recent and " 



•" 





Post-Pliocene. 

 2. Pliocene. 



._ Tertiary, Supracretaceous,* 





3. Miocene. 





or Cainozoic.f 





4. Eocene. 



j 





d 



5. Chalk. 



■ 





'8 



6. Greensand and Wealden. 









7. Upper Oolite, including the Purbeck. 





8. Middle Oolite. 





'» Secondary, or Mesozoic. 





9. Lower Oolite. 









10. Lias. 









11. Trias. 



. 



- 





12. Permian. 



' 



" 





13. Coal. 







zS 



14. Old Red Sandstone, or Devonian. 





o 



15. Upper Silurian. 





- Primary. 



- o 



16. Lower Silurian. 









17. Cambrian and older fossiliferous strata. J 



\ 



It is not pretended that the three principal sections in the above table, 

 called primary, secondary, and tertiary, are of equivalent importance, or 

 that the eighteen subordinate groups comprise monuments relating to 

 equal portions of past time, or of trie earth's history. But we can assert 

 that they each relate to successive periods, during which certain animals 

 and plants, for the most part peculiar to their respective eras, have flour- 

 ished, and during which different kinds of sediment were deposited in the 

 space now occupied by Europe. 



If we were disposed, on palseontological grounds,^ to divide the entire 

 fossiliferous series into a few groups less numerous than those in the above 

 table, and more nearly co-ordinate in value than the sections called pri- 

 mary, secondary, and tertiary, we might, perhaps, adopt the six groups or 

 periods given in the next table. 



At the same time, I may observe, that, in the present state of the 

 science, when we have not yet compared the evidence derivable from all 

 classes of fossils, not even those most generally distributed, such as 

 shells, corals, and fish, such generalizations are premature, and can only 

 be regarded as conjectural or provisional schemes for the founding of 

 large natural groups. 



* For tertiary, Sir H. De la Beche has used the term " supracretaceous," 

 a name implying that the strata so called are superior in position to the 

 chalk. 



\ For an explanation of Cainozoic, see p. 95. 



\ Palaeontology is the science which treats of fossil remains, both animal and 

 vegetable. Etym. vaXaios, palaios, ancient, ovra, onta, beings, and hoyos, logos, a 

 discourse. 



