PLATE XVIII Continued. 



PLEUROTOMARIA NODOMARGINATA 



Fig. 15. Enlargement to three diameters of a typical specimen, from the lower portion of the 

 Carboniferous Group. 



METOPTOMA PEROCCIDENS 



Fig. 16. Summit view, showing the outline and the radiating dark lines and fine concentric 

 striae. 



ORTHOCERAS RANDOLPHENSIS ? 



Fig. 17. View of a crushed fragment of the tube. 



BELLEROPHON TEXTILIS 



Ffg. 18. View of broken specimen, showing the surface characters and general form. 



EUOMPHALUS(S.) SUBRUGOSU8 



Fig. 19. Summit view of a small characteristic specimen. 



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