Ch. XVIL] fossils of upper cretaceous rocks. 



247 



of which are distinguished by a fibrous texture, and are often met with in 

 fragments, having probably been extremely friable. 



Fig. 271. 



Fig. 272. 



Pecten 5-costatus. 

 White chalk, upper and 

 lower greensands. 



Plagiostoma Hoperi, Sow. 



Syn. Lima Hoperi. 



■White chalk and upper 



greensand. 



Plagiostoma spinoaum, Sow. 



Syn. Spondylus spinosus. 



Upper white chalk. 



Of the singular family called Hudistes, by Lamarck, hereafter to be 

 mentioned as extremely characteristic of the chalk of Southern Europe, a 



Fig. 274 



Fig. 275. 



Inoceramus Lamarckii. 



Syn. Catillus Lamarckii. 



White chalk (Dixon's GeoL Sussex, Tab. 23, 



fig- 29). 



Ostrea vesicularis.~ Syn. Gryphma ghbosa. 

 Upper chalk and upper greensand. 



single representative only (fig. 278) 

 chalk of England. 



has been discovered in the white 



Fig. 276. 



Fig. 27T. 



Ostrea columba. 



Syn. Gryphcea columba. 



Upper greensand. 



Ostrea carinata. Chalk marl, upper and 

 lower greensand 



