290 



PLATE XIII 



Page 



Figs. 1,2. Schizodus cuneatus Meek 223 



Lower Mercer limestone: Licking County, Flint Ridge, 



Locality 47. 

 Fig. 1. Right valve. 

 Fig. 2. Left valve. 



Figs. 3, 4. Aviculopecten herzeri Meek 226 



Fig. 3. After Mark. Conemaugh formation: Porters- 



ville limestone, Portersville, Ohio. 

 Left valve showing the average size of specimens from the 



Potts ville formation. 



Fig. 4. McArthur member: Vinton County, Elk Town- 

 ship, Moore mine, Locality 84. 

 "Squeeze" of left valve of an extremely large specimen. 



Figs. 5, 6. Deltopecten scalaris Herrick 228 



Lower Mercer member: Scioto County, Vernon Township, 



Locality 31. 

 Fig. 5. "Squeeze" of left valve of a specimen of average 



size. 

 Fig. 6. Internal cast of left valve showing delthyrium. 



Figs. 7, 8. Crenipecten foerstii Herrick 230 



Lower Mercer limestone: Muskingum County, southeast 



of Frazeysburg, Locality 43. 

 Fig. 7. Left valve. xl| 

 Fig. 8. Right valve. 



Fig. 9. Entolium aviculatus (Swallow) 232 



Lower Mercer limestone: Muskingum County, Rock Cut, 



Locality 28. 

 Left valve of specimen of average size. 



Fig. 10. Lima retifera Shumard 233 



After Mark. Conemaugh formation: Portersville lime- 

 stone, Portersville, Ohio. 



Right valve showing average size of the species in the 

 Pottsville formation. 



Figs. 11 to 13. Astartella concentrica (Conrad) 241 



Fig. 11. Right valve. Lower Mercer member: Perry 



County, Somerset, Locality 35. x2 Hyde collection 826. 



Fig. 12. Right valve. Upper PottsviUe (McArthur)?: 



Hocking County, Carbon Hill, Ohio. Slightly enlarged. 



Fig. 13. Left valve, slightly enlarged. Same locality. 



Fig. 14. Astartella newberryi Meek 242 



Lower Mercer limestone: Muskingum County, southeast of 



Frazeysburg, Locality 43. 

 Left valve. 



Fig. 15. Allerisma terminate Hall 234 



Lower Mercer limestone: Licking County, Flint Ridge, 



Locality 48. 

 Left valve. 



Figs. 16, 17. Pleurophorella sesquiplicata Price 235 



Lower Mercer member: Vinton County, Rock Hollow, 



Locality 34. 



Fig. 16. "Squeeze" of right valve of average size. 

 Fig. 17. Right valve of another specimen. x2 



(Continued on page 291) 



