PLATE X. 



Fig. 



1, 2. Terebratula perovalis, Sou: The original specimens now in Mr. J. de C. 



Sowerby's collection. 



3. „ ,, From the Inferior Oolite, Dundry. 



4. „ „ From the Inferior Oolite of Dimnington. 



5. „ „ The largest specimen, I believe, yet found in 



England. 



6. „ „ Interior. 



7. Terebratula impressa, De Buck. var. From the Inferior Oolite ; in the British 



Museum. 



8. Orbicula reflexa, Sou: From the Lias ; in the British Museum. 



