PLATE LIV 



PAG0 



Figs. 1-4. CAMAROTCECHIA EXIMIA (Hall) 579 



1. Ventral valve. Town Creek, 4596. 



2. Cast of interior of ventral valve. Allegany Grove, 1860. 



3. Cast of interior of dorsal valve. Western Maryland Railroad, 2 



miles west of Pawpaw, 4703. 



4. Anterior view showing slight development of sinus. X 2. Town 



Creek, 4596. 

 Jennings formation, Chemung member. 



Figs. 5-8. LIORHYNCHUS MESACOSTALE Hall 581 



5. Ventral valve. 



6. Cast of interior of ventral valve. 



7. Cast of interior of ventral valve of young individual. 



8. Cast of interior of ventral valve of a somewhat crushed individual. 



Jennings formation, Parkhead member, Williams Road, 3% 

 miles east of Cumberland, 1393. 



Fig. 9. LIORHYNCHUS CF. MUI/TICOSTUM Hall 581 



Exterior of ventral valve. Jennings formation, Parkhead member (?), 

 National Road, west side of Green Ridge. 



Figs. 10-16. LIORHYNCHUS GLOBULIFORME (Vanuxem) 582 



10-12. Dorsal, anterior and ventral views of an internal cast of an 

 unusually elongate individual. Yellow Springs Road, 3 miles 

 east of Berkeley Springs, W. Va., 1124. 



13. Enlargement of muscular scars and hinge of ventral valve. X 3. 



National Road, east of Millstone, 1122. 



14. Cast of interior of dorsal valve of usual form. Western Maryland 



Railroad, 2 miles west of Pawpaw, 1300. 



15. Enlargement of hinge and muscular scars of fig. 14. X 4. 



16. Cast of interior of dorsal valve. Locality not known. 



Jennings formation, Woodmont member, Ithaca fauna. 



Figs. 17-22. PUGNAX PUGNUS VAR. ALTUS Calvin 583 



17-19. Ventral, dorsal and side views of internal cast. Woodmont, 1000. 



20. Cast of interior of a dorsal valve bearing more pronounced angular 



plications. 



21. Enlargement of muscular scars and hinge of ventral valve. X 3. 



Same locality as figs. 17-19. 



22. Enlargement of hinge of dorsal valve. X 3. Yellow Springs Run 



Road, 3 miles east of Berkeley Springs, West Virginia, 510 feet 

 west of beginning of section. 

 Jennings formation, Woodmont member, Ithaca fauna. 



Fig. 23. CRYPTONELLA CF. EUDORA Hall 584 



Internal cast of a ventral valve. Jennings formation, Chemung mem- 

 ber (?), Williams Road, Polish Mountain. 



137 



