PLATE VI. 



AVICULOPKCTEN PKINCEPS. 

 rage 1. 

 See Plates 1, 5, 24 anJ 81. 

 Fig-. 1. A large loft valve, much extended posteriorly. 



Hamilton group. Seneca lake, N. T. 

 Fig. 2. The impression of the exterior of a large right valve, showing the ligaraental area. The spot near 

 the middle of the valve has been caused by the attachment of a Crania to the exterior of the 

 shell. Hamilton group. Hamilton, N. ¥. 

 Fig. 3. An impression of the interior of a right valve. The striated ligamental area is shown in the 

 specimen, but not represented in the tigui'e. 



Hamilton group. Hamilton, Madison Co., N. Y. 

 Fig. 4. An imperfect left valve. 



Fig. 5. The right valve attached to the preceding, showing the comparative size and ornamentation. 

 Fig. 6. A small oblique left valve. The hinge-line should be represented as straight, and with a strong 



ligamental area. 

 Fig. 7. A sjiecimen presei'ving both valves. 



Hamilton group. Borodino, N. Y. 

 Fig. 8. A left valve, showing the ordinary characters of the species. The ligamental area is preserved 

 in the specimen, but not here i-epresentcd, and the hinge-line is too short in the figure. This 

 valve is associated with, and probably belonged to the right valve shown in figure 3. 

 Hamilton group. Hamilton, N. Y. 

 Fig. 9. An imperfect left valve. 



Hamilton group. SkaneateUs lake, iV. Y. 



