636 



THE WONDERS OF GEOLOGY. 



Lect. VI. 



fauna of Faxoe* was produced more by geographical condi- 

 tions, such, for example, as the local shallowness of that part 

 of the cretaceous sea, than by any general change in the 

 creatures inhabiting the ocean, effected in the period that 

 may have intervened between the formation of the white 

 chalk and the Faxoe limestone." 



The remains of sponges are very frequent in the flinty 

 chalk, and in many places not only do they swarm in the 

 limestone, but also in the flints ; so that almost every nodule 

 1 2 



4 5 



Lign. 139. — Fossil Poriferous Zoophytes; from Faringdon, Berks. 



(Collected and drawn by Miss Ellen Marin Mantell.) 



Fig. 1. Tragos peziza. S. Verficil/ipora anastomosans. 

 2 and 4. Scyphia. 5. Tragos? 



encloses a sponge or other poriferous zoophyte. The green - 

 sand in some localities contains immense numbers of porifera\ 



* A locality in Denmark, where these deposits are best displayed. 

 See Geol. Trans, vol. v. new series. 



