PLATE VI. 
Phacops cristata. 
Page 14. 
See Plate 8 a. 
Fig. 1. The cephalon. A cast of the lower surface, somewhat flattened and restored at the left genal angle. 
Schoharie grit. Knox, Albany county. 
Fig. 2. Profile view of another cephalon. A cast, slightly flattened upon the glabella. 
Schoharie grit. Near Clarksville, Albany comity. 
Pig. 3. Profile view of an uncompressed cephalon, showing the nm-mal convexity and the strong genal spine. 
Fig. 4. Dorsal aspect of the same. 
Schoharie grit. Near Clarksville, Albany county. 
Fig. 5. Lower aspect of a cephalon, showing the protuberance of the glabella, the frontal sulcus and 
epistoma. The drawing fails to represent the crenulations upon the sulcus near the genal 
extremities. 
Schoharie grit. Schoharie, Schoharie county. 
Fig. 6. Profile view of a small cephalon ; a cast of the interior. 
Fig. 7. Dorsal aspect of the same. 
Schoharie gi'it. Albany county. 
Fig. 8. A cephalon referred with doubt to this species. 
Schoharie gi-it. Albany county. 
Fig. 9. A fragment of a young individual, composed of the'thorax and pygidium and retaining the crust. 
The specimen is enlarged to two diameters and shows the axial row of spines. 
Schoharie grit. Near Clarksville, AlbaJiy county. 
Fig. 10. A nearly entire individiial, drawn from an impression obtained from a natural mould of the dorsal 
surface. In the diawing the axial spines and the light genal spine ai’e not given sufficient 
prominence. 
Schohai'ie grit. Albany county. 
Fig. 11. A fragment retaining a ^lortion of the thorax and pygidium, showing the axial splines and the 
duplicate pleural annulations on the pygidium. 
Corniferous limestone. Indian quarries, Onondaga county. 
Fig. 12. A pygidium retaining a portion of the crust and showing the character of the pleural annulations. 
Fig. 13. Profile view of the same. 
Schoharie grit. Schoharie, Schoharie county. 
Fig. 16. A cephalon retaining the normal convexity of the glabella and impressions of 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 cephalon denuded of its crust, and showing the cheek-spines. 
Fig. 19. Profile of the same, showing the crenulations upon the frontal sulcus. 
Corniferous limestone. 
Fig. 22. A smaller cephalon, retaining normal convexity and showing the tuber(',les upon the glabella. 
Fig. 23. The under surface of the same, shelving 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 di-awing. 
Upper Helderberg limestone. Clarence Holloio, Erie county. 
Fig. 24. A small cephalon partly denuded of its crust, showing strong genal spines. 
Fig. 25. Profile view of the same. 
Upper Helderberg limestone. Cayuga, Province of Ontario. 
