156 



" Embedded in tl" e substance of tbe Coral is a Gastrochcena, 

 (Gastrocliocna Moreana, Buvignier,) and the surface is sometimes 

 obscured by a slender species of Vermilia. Near the bottom 

 of each layer, and also in the Eubble and indurated Clay 

 forming the separations between each growth of Coral, are foimd 

 abundantly, Littorina muricata, and more rarely Trochotoma 

 ternata, Turbo funiculatus, Nerita Icevigata, and other littoral 

 gasteropods. Commonest amongst the bivalves are Gastrochcena 

 Moreana, Area cemula, Cueulloea pectinata, and Modiola inclusa. 

 Of the large bivalves, the abundance and character of which 

 in the true Coralline Oolite indicate deeper water and an 

 undisturbed condition of the sea, there are few or none. 



" Cidaris Smithii has been discovered in the Ayton Quarry 

 only, but Pseudodiadema versipora is not uncommon in them all. 



" The inference suggested is, that after the elevation of the 

 Coralline Oolite proper, has come a period of depression, during 

 which the land has again been partially submerged and the 

 Coral reefs constructed — this period having preceded the 

 commencement of the Cretaceous era, the Geological evidence 

 of the transition to which is involved in much obscurity in 

 this vicinity. 



" The Mollusca of the subjoined list are found in the Coral. 



"MOLLTJSCA IN THE CoRAL ReEFS. 



Turbo funiculatus, Phillips 

 Trochotoma ternata, Phillips 

 Littorina mwricata, Sowerby 

 Phasianella striata, Sowerby 

 Natica clymenia, D'Orbigny 

 Nerita Icevigata, Sowerby 

 Phillips 



(bellulata,) Bean, MS. 



Neritopsis Guerrei, Deslongchamps 

 Cerithiu/m Limceformis, Roemer 

 Nerinea fasciata, Voltz. 



fusiformis, D'Orb. 



Exogyra mima, Phillips 



