PLATE XXVII 



PAGE 



Figs. 1-6. PAL^ONEILO EMARGINATA (Conrad) 241 



1. Left valve, showing the strong concentric ridges. Evitts Creek. 



2. Left valve of shorter form. Hancock-Harrisonville Road, about 



2 miles north of Hancock. 



3. Right valve of same specimen. 



4. External impression of right valve. McCoys Ferry. 



Romney formation, Hamilton member. 



5. 6. Right and left valves. Hamilton formation, New York. 



Fig. 7. PAL^ONEILO TENUISTRIATA Hall (?) 242 



Right valve of a broken and mostly exfoliated specimen. Romney 

 formation, Hamilton member, McCoys Ferry. 



Figs. 8, 9. PAL^EONEILO TENITISTRIATA Hall 242 



Left and right valves. Romney formation, Hamilton member, near 

 Cumberland. (After Hall.) 



Figs. 10-13. PALVEOXEILO CLARKEI Prosser n. sp 244 



10. Left valve. 



11. Broken left valve, sinus at anterior end caused by crushing. 



12. Right valve, shortened by the breaking away of the posterior end. 



13. Interior of hinge line of No. 12 enlarged, showing the taxodont 



dentition. X 2. 



Romney formation, Hamilton member, right bank of Potomac 

 River, about 3 miles below Cumberland. 



Figs. 14, 15. PAL^ONEILO ROWEI Prosser n. sp 244 



14. Internal impression of left valve, showing muscular markings and. 



hinge crenulations. 



15. Squeeze of same specimen. 



Romney formation, Hamilton member, McCoys Ferry. 



Fig. 16. PAL^ONEILO MARYLAXDICA Prosser n. sp 245 



Right valve. Hancock-Harrisonville Road, about 2 miles north of 

 Hancock. Romney formation, Hamilton member. 



no 



