PLATE XII 



PAGE 



Figs. 1-8. CHONETES SCITULUS Hall 150 



1. Interior of ventral valve. X l 1 /^. 21st Bridge. 



2. Ventral valve. X 1%. Right bank of Potomac about 4 miles south 



of Cumberland. 



3. Ventral valve. X \Vz- Same locality. 



4. Dorsal valve of same specimen, showing cardinal area and spines of 



ventral valve. X 1%. 



5. Partly exfoliated dorsal valve (?). X 1%. Iron Bridge over Town 



Creek northeast of Oldtown. 



6. Interior of ventral valve. X 2 1 / i. B. & O. R. R. cut opposite Han- 



cock. 



7. Dorsal valve (?). X 1%. McCoys Ferry. 



Romney formation, Hamilton member. 



8. Dorsal valve, showing cardinal area and deltidium. Hamilton 



formation, New York. 



Figs. 9-13. CHOXETES LEPIDUS Hall 153 



9. Ventral valve partly exfoliated, showing two cardinal spines. X 3. 

 Evitts Creek. 



10. Valve showing three cardinal spines. X 4. Evitts Creek. 



11. Interior of dorsal valve (?). X 3. Iron Bridge over Town Creek, 



northeast of Oldtown. 



12. Interior of ventral valve, showing cardinal teeth. X 3. West of 



Tonoloway Ridge. 



13. Ventral valve (?). X 3. B. & 0. R. R. cut opposite Hancock. 



Romney formation, Hamilton member. 



Figs. 14-21. CHONETES vicixus (Castelnau) 155 



14. Ventral valve. Evitts Creek. 



15. Portion of the same near the umbo, showing the intercalation of 



radiating and fine concentric striae. X 8. 



16. Partly exfoliated ventral valve showing one cardinal spine. X 1^4' 



Iron Bridge over Town Creek, northeast of Oldtown. 



17. Interior of ventral valve. X 1 1 A. McCoys Ferry. 



18. Interior of dorsal valve. X 2. Hancock-Harrisonville Road, 2 



miles north of Hancock. 



19-20. Exteriors of ventral valves. X 2. Same locality. 

 21. Interior of the dorsal valve. X 3. Same locality. 

 Romney formation, Hamilton member. 



