270 



OUR COMMON BRITISH FOSSILS. 



dead shell of an Ammonite, etc. — where it settled, there 

 it grew, adapting its expanding shell to the object it 



Fig. z^i^.—Ostrea vesctctilaris 

 (Chalk) 



Fig. 2SS-—Cardium Lil^ 

 lannnt (Greensand). 



Fig. 256. — Exogyra 

 conica (Greensand). 



was attached to ; and so in the Chalk-pits near Nor- 

 wich we find this very common fossil more than half 



Fig. 2<,1.—Pecien quadri- Fig. 258. — Inoceramtis 

 costaUis. concentricus. 



encircling the solid shafts of Be- 

 lemnites, or actually taking the 

 impression of some coiled Am- 

 monite. ■^'2* ^59- - Rostellaria ParMnsonu. 



Other bivalve mollusca of the Chalk are the grace- 

 ful Inoceramtis mytiloides and /. labiatus, the latter 

 not unfrequent near Dover, whilst the former is found 

 generally in the Lower White Chalk. 



