NORTHUMBERLAND AND DURHAIM. 285 



occurrence of this sliell in the above localities affords me much 

 pleasure, as it enables me to correct the false impression which 

 this learned Permian paLxontologist has so long and so unneces- 

 sarily entertained. 



On a future occasion I hope to make a few remarks on the 

 remaining portion of the fauna of the Permian System. 



EXPLANATION OF PLATE XL* 



Figs. 1, 2. Productus lafirosirafus, Howse, from the sliell-limastone, Dalton-le- 

 Dale. 



Fi(/s. 3, 4. CamarojyJioria Uambktonensis^ Howse, from the shell-limestone 



Humbleton. 

 ■ Figs. 5, 6. Spiriferina crisfata Schloth. sp., from the shell-limestone, Tunstall. 



Fig. 7. Solemya normalise Howse, from the shell-limestone, Humbleton. 



Figs. 8, 9. Solemya biarmica, De Verneuil, from the shell-limestone, Silksworth. 



Figs. 10-13. Edmondia elongafa^ Howse, from the shell- limestone, Tunstall 

 and Humbleton. 11. Cast showing fissure left bj^ the subumbonal 

 blade or plate. 12. Hinge-margin removed, showing the form of the 

 subumbonal blade. 



Figs. 14, 15. TelHna Dunelmensis, Howse, from the shell-limestone, Humbleton. 



Figs. 16, 17.- Cahjptrcea antiqua^ Howse, from the shell-limestone, Tunstall. 



Fig. 18. Chemnitzia Altenburgensis, Geinitz, sp, = Turritella Phillipsii, Howse, 

 from tlie shell-limestone, Tunstall. 



Figs. 19, 20. Littoi'ina heUciiia, Schloth. sp. ; varieties with nearly obsolete spiral 

 bands, from the shell-limestone, Tunstall. 



Figs. 21-25. Phurotomaria antrina., Schloth. sp. 23. Typical form and varie- 

 ties, from the shell-limestone of Silksworth and Dalton-le-Dale. 



Fig. 26. Nautilus Frieslebeni^ juv., Geinitz, from the shell-limestone, Silksworth. 



Fig. 27. Tlieca ? Kirkhyi^ n. s., from the shell-limestone, Tunstall. 



Fig. 28. Eetepoj^a Ehrenbergi^ Geinitz, from the shell-limcsKme, Silksworth. 

 o, portion of the large individual figured in "Perm. Mou." t. 5. f. 1. ; 

 6, young individual; c, fragment enlarged, showing interstices and 

 polype-cells ; c/, fragment slightly enlarged, showing the reverse or 

 non-celluliferous surface. 



Fig. 29. CaryophjlKa quadrijida, Howse, from the shell-limestone, Humbleton ; 

 a, c, coral-stem, natural size ; b, cast showing the position of the la- 

 minae or plates. 



* The use of this plate has been kindly pennittcd b.v the editor of the "Annals of Natural 

 History," and corresponds with pi. 4, vol. xix. of I hat Avork. 



VOL. III. I'T. IV. 1 M 



