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PLATE XVI 



Page 



Figs. 1, 2. Zygopleura plenum (Herrick) 258 



Fig. 1. "Squeeze" of internal cast. Lower Mercer lime- 

 stone: Muskingum County, near Fairview school, 



Locality 45. 

 Fig. 2. Lower volutions of another specimen. McArthur 



limestone: Vinton County, Elk Township, Moore mine, 



Locality 84. xl 



Figs. 3, 4. Plagioglypta prosseri n. sp 245 



Fig. 3. "Squeeze" of internal cast of a cotype. Lower 



Mercer member: Muskingum County, near Fairview 



school, Locality 45. 

 Fig. 4. Another specimen with the shell partly preserved. 



Lower Mercer member: Licking County, Flint Ridge. 



From the collections of Dr. G. H. Girty. 



Figs. 5, 6. Orthoceras isogramma Meek 266 



Fig. 5. A portion of the shell above the living chamber. 



Lower Mercer limestone: Licking County, Flint Ridge, 



Locality 49. 

 Fig. 6. A fragment of a much larger specimen. Upper 



Mercer member: Coshocton County, Jefferson Town- 

 ship, Locality 71. 



Figs. 7, 8. Metacoceras pottsvillensis n. sp 269 



Lower Mercer member: Lawrence County, near Hanging 



Rock, Locality 3. 

 Fig. 7. Lateral view. 

 Fig. 8. Cross section near body whorl. 



Fig. 9. Phillipsia trinucleata Herrick % 274 



Lower Mercer limestone: Licking County, Flint Ridge, 



Locality 48. 

 Pygidium of typical size. 



