PLATE m— Continued. 



AVICULOPECTEN INSIGNIS. 



Page 34. 



See Plates 1 and 81. 



Fi{r. 13. The interior of a right valve imbedded in shale, showing the ornamentation a.< it ajipears on the 



interior of the shell. 



Hamilton group. Hamburg, Srie Co., N. Y. 



AviCULOPECTEN ORNATUS. 

 Page 37. 

 See Plate 2. 

 Fifr. 14. 'I"he interior of a left valve imbedded in shale, X 2. 



Hamilton group. CaiiawUiif/ua lake, N. Y. 



AviCULOPECTEN MUCRONATUS. 

 Page 38. 

 Fig. 15. The interior of a left valve imbedded in shale. 



Hamilton group. Dresden, Yates Co., N. Y. 



AviCULOPECTEN LAUTUS. 

 Page U. 

 See Plate 81. 

 Fig. 16. 'ITie interior of two attached valves imbedded in shale, showing their comparative form and pro- 

 portions. 



Hamilton group. West BloomJUld, N. Y. 

 Fig. 17. ITie interior of a left valve preserved a.s the preceding. Another figin-e of this specimen is given 

 on plate 81, fig. 5, taken from an impression of this mould. 



H.TKiiltiin n-roii].. York Centre, Livingston Co., N. Y. 



AviCULOPECTEN EXACUTUS. 



Page S. 

 Fig. 18. 'ITie interior of ii left valve imbedded in shale. 



Hamilton group. Hamburg, Erie Co., N. Y. 

 Fig. 10. A small left valve with the anterior ear imperfect. 



Hamilton group. Canandaigua lake, N. Y. 

 Fig. 20. A large impei'fect left valve. The beak is represented as too acute, and the concentric lamella' 

 are not shown an on the specimen. 



Hamilton group. Hamburg, Erie Co., N. Y. 

 Fig. 21. A left valve deiuided of the test. The .specimen shows the pallial line and muscular impression. 



as described in the text. 

 Fig. 22. 'I'he upper portion of a right valve preserving the test. 

 Hamilton gi-oup. Hamburg, Erie Co., N. Y. 



