PLATE 2. 



Page 

 Fig. 1. LiNOULA C ERYX 5 



1. An imperfect valve ia areoaceous rock. 



Fig. 2. LiNOULA DESIDERATA 6 



2 An imperfect valve enlarged to two diameters. 



(Fig. 3. LiNOULA MANNI 6 



3. A single valve of natural size. , , _.„_., 



* .banniJnoO— r 5iTA.fi 



Figs. 4-6. LlNGULA NCDA 10 



4, 5, 6. Separate valves presenting the nsnal variety of form of this species. 



Fig. 7. LiNOULA PUNCTATA , 10 



7. Profile of a specimen retaining both valves in connexion. 



. 11 " I 



Fig. 8. LiNOULA LioEA var .'. A ?{ . 8 



8. A specimen of this species from the Portage group, at Trumansburgh, N. Y. 



Fig. 9. LiNGULA DELIA 12 



9. A specimen of the natural size, showing the mark of a linear septum. 



Figs. 10, 11. LiNOULA DENSA ^ . i . ..i . i. « *i *.».». w. . 11 



10,11. A ventral and dorsal valve of the natural size. ' ' '''.„ ' ^. 



Fig. 12. LiNOULA LEANA ., j,. .^.^^ ,j,,^j 9 



12. A ventral valve of the natural size. 



Fig. 13. LiNOULA MAIDA 9 



13. A specimen of the natural size. 



Figs. 14, 15. LiNOULA ALVEATA 12 



14. An impression with the remains of the shell on the margin, showing the mark of a longitu- 



dinal septum. 

 16. A larger individual; the impression in shale shows what appears to have been a triple 

 medial septum. 



Figg. 16, 17. DiSCINA TULLIA 22 



16. Vertical view of a dorsal valve, natural size. 



17. Profile of the same. 



Fig. 18. DiSCINA HUMILIS 16 



18. View of a ventral valve. 



