291 



PLATE XIII Continued 



Page 



Figs. 18,19. Pleurophorella geinitzi (Meek) __ 235 



After Mark. Conemaugh formation :Portersville limestone, 



Portersville, Ohio. 



Fig. 18. "Squeeze" of right valve. x5 

 Fig. 19. Same, natural size. 



Figs. 20, 21 . Pleurophorus tropidophorus Meek __ 240 



Fig. 20. Right valve. Lower Mercer limestone: Mus- 



kingum County, Locality 45. 



Fig. 21. "Squeeze" of right valve of another specimen. 

 Lower Mercer limestone: Licking County, Flint Ridge, 

 Locality 47. 



