PLATE VI. 



Phacops CRISTATA. 



Page 14. 



See Plate 8 \ 



Fig. 1. 'I'll'- eephalon. A cast of the lower surface, somewhat flattened and restored at the left genal angle. 



Schoharie grit. Knox, A ■ ity. 



Fig. 2. Profile view of another eephalon. \ ca '. slightly flattened upon the glabe 



Schoharie grit. Near ClarksviUe, A a ity. 



Fig-. :!. Profile view of an uncompressed eephalon, showing the normal convexity ami the tronggenal spine. 

 Fig. 4. Dorsal aspect of the same. 



S i iharie grit. Near ClarksviUe, Albany county. 

 Pig. 5. Lower aspect of a eephalon, showing the protuberance of the glabella, the frontal sulcus arid 

 epistoma. The drawing fails to represent the crenulations upon the sulcus near the- genal 

 extremitie 



Schoharie grit. Schoharie, St ounty. 



Fig. ti. Profile view of a small eephalon : a BUS* of tin- interior. 

 Fig. 7. Dorsal aspect of the sai 



Schoharie grit. A '//. 



Fig. 8. A cephJtlon referred with iloufet to this species: 



Schoharie grit. A ity. 



Fig. 9. A fragment of a young- individual. 51 of the thorax and pygidium and retail ing the crust, 



Tin- ape -i in. • r 1 is enlarged to two diameters and shows the axial row of spines, 

 oharie grit. Near ClarksviUe, A mty. 



Fig. 10. A nearly entire individual, drawn from an impression obtained from a natural mould of the doreal 

 surface. In the drawingthe/axial spinesiand the right genal spine are net given sufflciertl 

 prominence. 



Schoharie grit. Albany county. 

 Fig. 11. A fragment retaining a portion of the thorax ancj jjygidium, showing the axial spines and the 

 duplicate pleural, ambulations on the pygidium. 



Corniferous limestone! Indian quarries', Ononddpa.cmi 

 Fig. 12. A pygidium retaining a portion id' the crust and showing the charaeter of 'the pleural aunulatii 

 Fig. 13. Profile view of the same. 



Schoharie grit. ScTioharie, Schoharu county. 

 Fig. 1 » '> . A eephalon retaining the normal convexitj of the glabella and impressions ol the tubercles upon 



its surface, but not showing the occipital or the cheek-spines. 

 Fig. 17. Front view of the same. 

 Fig. 20. The under surface of the same. 

 Fig. 21. Profile view of the same. 



Corniferous limestone. Helderberg mountains. 

 Fig. 18. A eephalon denuded of its crust, and showing the cheek-spines. 

 Fig. 19. Profile of the same, showing the crenulations upon the frontal sulcus. 



t !< irniferous limestone. 

 Fig. 22. A smaller eephalon. retaining normal convexity and showing the tubercles upon the glabella. 

 Fig. 23. The under surface of the same, showing the broad doublure. The crenulations upon the lateral 

 branches of the frontal sulcus are not made sufficiently conspicuous, and they do not appear on 

 the frontal limits of this sulcus, as represented in the drawing. 



Upper Helderberg limestone. Clarence Hollow, Erie county. 

 Fig. 24. A small eephalon partly denuded of its crust, showing strong genal s] 

 Fig. 25. Profile view of the same. 



Upper Helderberg limestone. Cayuga, Province of Ontario. 



