Explanation of the Plates. 



331 



PLATE II. 



Fig. 1. 

 " 2. 



CONOCEPHALITES SHUMARDI. 



A head, natural size. 



A pygidium, natural size. 



CONOCEPHALITES NASUTUS. 



Fig. 3. A small head, natural size. 

 " 4. A larger head. 

 " 5. A very conical glabella. 



44 6 & 7. Two forms of cheeks, associated with the heads. 

 " 8. A pygidium enlarged three diameters. 



" 9. A pygidium enlarged two diameters, with two nodes on the terminal segment. 

 The figures 8 and 9 represent two pygidia found associated with the heads of Conocephalites 

 nasutus. It is impossible at this time to determine which of them belong to the heads described. 



Fig. 10. A head, natural size. 

 44 11. Impression of a cheek. 



" 12. A thoracic segment, in outline, occurring on the same stone with figures 10, 11 & 16. 

 " 13, 14, 15. Thoracic segments from different parts of the body. From Lacrosse. 

 " 16. A pygidium. From Trempaleau. 



Fig. 17. A small specimen twice enlarged. From Kickapoo. 

 " 18. A head, natural size ; a shorter form, from Root river. 

 " 19. Profile of the same. 



" 20 & 21. Two forms of cheek, associated in the same rock. 

 " 22. Part of a thoracic segment. 

 " 23. A pygidium, natural size. 



CONOCEPHALITES EOS. 



Fig. 24. A head of this species, 

 " 25. An imperfect thoracic segment. 



CONOCEPHALITES WINONA. 

 Figs. 26, 27 & 28. A head, cheek and pygidium, enlarged three diameters. 



Fig. 29. A small head : from Trempaleau. 

 44 30. A larger head : from Black river. 

 " 31. A large head : from Root river. 

 44 32. Parts of thoracic segments. 



44 33. A pygidium partly restored, showing the peculiar furrows in the ribs of the lateral lobes ; 



CONOCEPHALITES ERYON. 



CONOCEPHALITES 



PERSEUS. 



CONOCEPHALITES IOWENSIS. 



from Black river. 



CONOCEPHALITES ANATINUS. 



Fig. 34. A glabella. 



44 35. A cheek, associated with the same. Three miles above Reed's landing, Lake Pepin. 



