288 



PLATE XII 



Page 



Figs. 1 to 4. Posidonia girtyi n. sp 214 



Lower Mercer member: Vinton County, Rock Hollow, 

 Locality 34. 



Figs. 1, 2. Right valves of two cotypes of medium size 

 showing small anterior auricle. 



Figs. 3, 4. Left valves of two cotypes of large size. 

 Figs. 5, 6. Posidonia vintonensis n. sp 216 



Lower Mercer member: Vinton County, Rock Hollow, 

 Locality 34. 



Fig. 5. Right valve of a cotype. x2 



Fig. 6. Left valve of another cotype. x2 

 Figs. 7 to 9. Naiadites elongata Dawson 220 



Figs. 7, 8. Right and left valves of two specimens show- 

 ing the usual condition of preservation. x2 Bear Run 

 coal member: Vinton County, Elk Fork, Locality 17. 



Fig. 9. Right valve of the most perfect individual found; 

 slightly enlarged. Sharon ore: Scioto County, head of 

 Higgins Run, John Alexander mine, Locality 3. 

 Figs. 10 to 13. Naiadites ohioensen.sp 221 



Sharon ore: Scioto County, head of Higgins Run, John 

 Alexander mine, Locality 3. 



Figs. 10, 11. Right valves of two cotypes, slightly en- 

 larged. 



Fig. 12. Left valve of another cotype, slightly enlarged. 



Fig. 13. Dorsal view of same specimen shown in Fig. 10. x2 

 Figs. 14 to 16. Schizodus subcircularis Herrick ' 225 



McArthur member: Jackson County, Monroe Furnace, 

 Locality 80. 



Figs. 14, 15. Right valves. 



Fig. 16. Left valve of another specimen. 

 Fig. 17. Schizodus affinis Herrick 223 



McArthur member: Jackson County, Monroe Furnace, 

 Locality 80. 



Left valve. 

 Fig. 18. Schizodus amplus Meek and Worthen ? 222 



Boggs member: Muskingum County, near Hopewell P. O., 

 Locality 26. 



Left valve imperfect in the posterior portion showing the 



muscle scars and pallial line. 

 Fig. 19. Placunopsis ? recticardinalis Meek 233 



Lower Mercer member: Licking County, Flint Ridge, 

 Locality 47. 



"Squeeze" of left valve showing superimposed markings. 



