PLATE LIII 



PAGE 



Fig. 1. SCHIZOPHOBIA STRIATULA ( Schlotheim) 572 



Cast of interior of ventral valve which approaches the next variety. 

 Jennings formation, Chemung member, Ellerslie, Penna., 1474. 



FigS. 2-9. SCHIZOPHORIA STRIATULA VAR. MARYLANDICA n. Var 574 



2-4. Internal casts of dorsal valves. 

 5. Internal cast of ventral valve. 

 6-8. Three ventral valves. 

 9. Dorsal valve. 



Jennings formation, Chemung member, Deer Park and vi- 

 cinity. 



Fig. 10. SCHIZOPHORIA STRIATULA (Schlotheim) ? 572 



Internal cast of ventral valve. Jennings formation, Parkhead mem- 

 ber, Rocky Run, 7 miles southeast of Cumberland. 



Figs. 11-16. CAMAROTCECHIA CONGREGATA VAR. PARKHEADENSIS n. var 575 



11. Ventral valve more elongate than usual. Parkhead member, 



National Road, east of Hancock, 1600. 



12. Cast of interior of ventral valve. Associated with fig. 11. 



13. Dorsal valve. Associated with preceding. 



14. Posterior view of cast of interior. Chemung member, National 



Road, Polish Mountain above 7th turn. 



15. Cast of interior of dorsal valve. Associated with fig. 14. 



16. Cast of interior of ventral valve. X 2. Associated with preceding. 



17. Cast of interior of ventral valve approaching C. sappho in form. 



Base of Parkhead member, road 1 mile north of Rocky Run. 6 

 miles southeast of Cumberland. 

 Jennings formation. 



Figs. 18-20. CAMAROTCECHIA CONTRACTA (Hall) 577 



18. Ventral valve of typical form showing sharp angular plications. 



Allegany Grove, 2957. 



19. 20. Ventral valves possessing less angular plications, approaching 



C. congregata var. parkheadensis. National Road, Polish Moun- 

 tain, above 7th turn. 



Jennings formation, Chemung member. 



Fig. 21. CAMAROTCECHIA CONTRACTA (Hall) var 577 



Cast of interior of ventral valve. Jennings formation, Chemung mem- 

 ber, National Road, east of Millstone, 3116. 



Figs. 22-25. CAMAROTCECHIA HORSFORDI (Hall) 578 



22. Ventral valve, doubtfully referred to this species. Chemung 



member, National Road, Polish Mountain above 7th turn. 



23, 24. Cast of interiors of ventral and dorsal valves. Parkhead mem- 



ber. 2% miles north of mouth of Sideling Hill Creek, 1700. 



25. Anterior view of shell. Parkhead member, Western Maryland 



Railroad, 2 miles west of Pawpaw. 

 Jennings formation. 



Figs. 26, 27. CAMAROTCECHIA ORBICULARIS (Hall) 579 



26. Cast of interior of dorsal valve. 2% miles southwest of Mountain 



Lake Park. 



27. Side view of dorsal valve. Jennings Run Road, 1 mile east of 



Barrelville. 



Jennings formation, Chemung member. 



136 



