220 



OUR COMMON BRITISH FOSSILS. 



growth of fossil Polyzoa, many of them allied to, if 

 not identical with, existing kinds, such as Cellepora, 



i 



Fig. 186. Diastopora ventricosa (highly magnified) 



Membranipora> Hornera, etc. Others are locally ex- 

 tinct, and can only be found in warmer seas. Near 



Fig. 187. Cells of Diastopora Oolitica 

 (highly magnified). 



Fig. 188. Fascicularia aurantiui 

 (Coralline and Red Crags). 



Orford the young geologist will find plenty of round 

 balls, which, when split open, reveal a radiated struc- 



