FOSSIL SEA' MATS, 



219 



species in superabundance is the " Coralline " Crag, 

 which took its geological name from their numerical 

 abundance, in the early zoological days when sea- 

 mats and sea-firs {Hydrozoa and Polyzod) were 

 grouped together as " corallines." 



a 



^ 





' ^"^^ ^(t^ ilis^ 



Fig. \^.—DiastoJ>orct ventricosa ; NS (natural size). 



The "re-deposited" Coralline or White Crag is 

 best seen in the neighbourhood of Aldborough and 

 Orford, in Suffolk, where it is about eighty feet thick, 

 and of a pretty cream-colour. The fossils in this 

 bed are abundant, but every one is encrusted with a 



