PLATE XXXI— Concluded. 



PAGE. 



Fig. 22. A glabella of Cyphaspis ClinTonensis, Foerste 524 



Cumberland Gap, Tennessee. 



Figs. 23-24. Rynchoneula decemplicata Sowerby ? 



23. A brachial valve and a side view of the same. 



24. Perhaps a young form of this species. Cumberland Gap, Tennessee. 



Fig. 25. Strophomena ( Stropheodo.nTa? ) corrugata Conrad. 



The elongated form figured first by Hall under this species, but not the typical 

 form of Conrad. Cumberland Gap, Tennessee. 



Figs. 26-29. Strophomena (Stropheodonta?) corrugata var. peuri-striata 

 Foerste. 

 More like that figured second b3' Hall under 5. corrugata. It is not impossible that 

 this may prove to be the typical form of Conrad. 



26. Brachial valve and a line indicating its lack of convexity. 



27. Pedicle valve with a line indicating its convexity. Cumberland Gap, Tennessee. 

 29. Pedicle valve of an unknown species and a line indicating its convexity. Cumber- 

 land Gap, Tennessee. 



Fig. 30. Pachydictya emarcescens, Foerste 599 



30a Part of a frond, with a section showing its convexity. 

 305 A part of the same magnified. Eaton, Ohio. 



Fig. 31. Pachydictya farcta Foerste 55g 



31(7 Part of a frond with a section showing its convexity. 

 315 Part of the same enlarged. Eaton, Ohio. 



Fig. 32. Pachydictya (Rhinodictya?) rudis Foerste 599 



32a Parts of two fronds with section showing their convexity. 

 325 A part of the left hand specimen enlarged Eaton, Ohio. 



Fig. 33. Pachydictya ( Rhinodictya ? ) rudis Foerste 559 



33a Parts ol two fronds with sections showing their convexity. 

 335 A part of the left hand specimen enlarged. Eaton, Ohio. 



