PLATE X. 



PAGE 



Figs. 1-3. Athyris subouadraTa Hall 472 



1 and 2. Dorsal and front views of a specimen of the prevailing form. 

 ?> Dorsal view of a specimen wi h a more strongly marked fold. 



Fig. 4. Schizodus Chesterensis M. and W..... 474 



i. View of a le(t valve, from Maxville, Ohio, formerly identified an 1 labeled by F B. 

 Meek. 



Fig. 5. Pinna Maxvillensis Whitf. 474 



5. View of a left valve slightly restored at the apex. 



Fig. 6. Aelorisma Andrewsi Whitf. 475 



6. View of a right valve Irom Newtonville, Ohio. The figure is slightly restored on 



the borders. 



Figs. 7-8. Aelorisma maxvileensis Whitf. 475 



7. View of a right valve, natural size. 



8. View of a specimen retaining both valves, one of which is slightly larger than the 



other, perhaps accidentally so. 



Figs. 9-11. Straparoleus simieis M. and W 476 



9-11. Lateral vertical ar.d basal views of a specimen showing the irregularly ex- 

 panded carinaticn on the m ddle of the shell. 



Fig. 12. Holopea Newtonensis Whitf. 477 



12. Side view of the specimen from which the description was drawn. 



Fig. 13. POLVPHEMOPSTS MELANOIDES Whitf. 478 



13. View of a specimen showing the form and proportions. 



Fig. 14. Macrocheieus subcorpulentcs Whitf 478 



IE View of the aperture. 



Figs. 15-16. Naticopsis ziczac Whitf. 477 



15 aud 16. View of the back o r the shell, natural size aud enlarged, showing the pecu 

 liar surface markings. 



Figs. 17-19. Bellerophon alternodosus Whitf 479 



17-19. Three views of the same specimen, which is slightly imperfect. 



Figs. 20-21. Bellerophon subl.-Eyis Hall 479 



20and21. Back and profile views of a specimen from which the shell is mostly re- 

 moved. The auriculations being only partially preserved and the front removed. 



Fig. 22. Nautilus (Temnocheilus) spectabilis M. and W 480 



22. Lateral view of the inner septate portion of a specimen from near Rushville, Ohio, 



showing the character of the shell. 



Fig. 23. Nautilus pauper Whitf 481 



23. View of the specimen described showing the outer chamber and the impression of 



the inner coils. 



