EXPLANATION OF THE PLATES. 



PLATE I. 



Fig. 



1. Phytolithus verrucosus, 



a. suppressed tubercles. 



c. longitudinal sulcus. 



2. Phytolithus verrucosus. 



b. traces of leaves. 



d. included, cylindrical body 



3. Fossil strobilus. 



a. tubular processes passing 

 from the internal part 

 to the surface. 



4. Phytolithus cancellatus, epi- 



dermal surface. 



Fig. 

 5. 



6. 



7. 



Phytolithus cancellatus, cortical 



surface. 

 Phytolithus cancellatus, ligneous 



surface. 

 Transverse section of siphonia. 

 Upper extremity of siphonia 



Websteri. 



Species of Mantellia. 



Fossil teeth from Stonesiield 

 slate. 



Palythoa. 



PLATE IL 



Fig. 

 1, 



represents the general form and 

 characters of the genus echi- 

 nus and cidaris ; the tuber- 

 cles being perforated in the 

 latter genius. 

 Clypeaster. 

 Galerites. 



> Fibularia, 



Fig. 



6. Clypeus. 



7. Cassidulus. 



8. Kchinarachnius. 



9. Ananchytes, the upper surface. 



10. Scutella. 



11. Spatangus (Cor. Marinum). 



12. Ananchytes, the under surface. 



13. Spatangus (Ovum Marinum, 



Brissus} . 



Fig. 



1. Planospirites. 



2. Oscana. 



3. Testacella. 



4. Patella. 



5. Fissurella, 



6. Emarginula, 



7. Concholepas. 



8. Stomatia. 



9. Argonauta. 



PLATE IIL 



Fig. 



10. Carinaria. 



11. Sigaretus. 



12. Haliotis. 



13. Calyptrea. 



14. Infundibulum. 



15. Crepidula, 



16. Dentalium. 



17. Siliquaria. 



18. Vermicularia. 



Fig. 



19. Seroula. 



20. Pup"a. 



21 . Aspergillum, 



22. 

 23. 

 24. 

 25. 

 26. 



Conus. 



C'ypraea. 



Ovula, 



Bulla. 



Terebellum. 



