﻿Gastropod 



(Helico- 



toma) 



Coral 



(Strepte- 



lasma) 



Astylo- 

 spongia 



Trilobites 

 (Trinucleus) 



(Calymene) 



(Asaphus) 



Crinoids 

 (Glypto- 

 crinus) 



Polyzoan 



Pterdnaea 



Graptolite 



(Dicho- 



graptus) 



Cystid 



(Echinos- 



phaera) 



Lampshell 



(Platys- 



trophia) 



(Ceraurus) 



ORDOVICIAN MARINE LIFE 



[To face page 22 



