THE CEPHALOPODA. 



217 



RANGE OF THE GENERA OF THE FOSSIL CEPHALOPODA IN 

 GEOLOGICAL TIME.^ 



Drawn up by the Eet. T. Wiltshire, M.A., r.G-.S., in 1867. See page 203. 







3 

 o 



a 

 O 



6 



s 

 3 



.2 



a 



a 



'a 



3 

 O 



O 



a 

 O 



1 



_3 



1. Argonauta . 



^ 















2. Enoploteuthis 



3. Plesioteuthis 





... ^ 

















4. Ommastrephes 



5. Loligo 





s 

 * 



S 

 f 















6. Teudopsis . 



7. Pliylloteuthis 



8. Beloteuthis . 





* 

















9. Geoteuthis . 





a 



■ 















10. Leptoteuthis 



11. Sepia . 



12. Belemnosis . 



* 



5, 



51 

















13. Beloptera . 



14. Heliceras . 



* 



* 



? 















15. Spiruhrostra 



16. Belemnites . 



* 



^ i 



i 















17. Belemnitella 





* 

















18. Belemnoteuthis . 





jl 



i 















19. Conoteuthis 





* 

















20. Xiphoteuthis 



21. Nautilus . 



22. Discoceras . 





* -J 



f 

 f 











» 



* 

 * 



23. Ophidioccras 



24. Gyroceras . 

















» 



* 

 * 



25. Cyrtoceras . 



26. Cyrtocerina 



27. Oncoceras . 

















* 



» 

 * 

 * 



28. Strep toceras 



29. Piloceras 



















* 



30. Lituites 



















* 



1 The stars opposite a genus in one or more of the columns show that the genus existed in the 

 geological period referred to in the column or columns. 



- The Jurassic formation includes the Oolite and the Lias. 



29 



