PLATE XXI. 



PAGE 



Fig. 1. Cancellaria geaciloides Aldrich var 128 



Ventral view of specimen from 1 mile southeast of Aiason Springs. 



Fig. 2. Cancellaria sp 129 



Much enlarged view of specimen from 2 miles below Potomac Creek. 



Figs. 3, 3a. Cancellaria (Narona) potomacensis n. sp 129 



3. Ventral view of specimen from 1 mile northeast of Piscataway. 

 3a. Dorsal view of same siiecimen. 



Figs. 4, 5, 5a. Volutilithes petrosus (Conrad) 130 



4. Pomonkej^ Xeck. U. S. Xational Museum. 



5. Dorsal view. Potomac Creek. 

 5a. Ventral view of same specimen. 



Figs. 6, 6a. VoLUTiLixnES sp 131 



6. Ventral view of cast. Aquia Creek. 

 6a. Dorsal vie^v of same specimen. 



Figs. 7, S. Caricella pyruloides ( ?) (Conrad) 131 



7. Spire and part of body whorl. Potomac Creek. ' 



8. Cast. Aquia Creek. 



Figs. 9, 9a. MiTRA marylandica Clark 132 



9. Dorsal view. Pomonkey Neck. U. S. National Museum. 

 9a. Ventral view of same specimen. 



Figs. 10, 10a. MiTRA pomonkensis n. sp 132 



10. Ventral view. Pomonkey Neck. U. S. National Museum. 

 10a. Dorsal view of same specimen. 



Fig. 11. MiTRA potomacensis n. sp 133 



Enlarged view. 1 mile northeast of Piscataway. 



Figs. 12, 12a. Latirits marylandicus n. sp 133 



12. Ventral view. 2 miles below Potomac Creek. 

 12a. Dorsal view of same specimen. 



373 



