Figs. 9, & 10. Different parts of the same specimen of a brachiopodous bivalve belonging to the genus _Productus_, so named from the lengthened or produced form of the convex valve. "This is generally filled with limestone, which conceals the internal structure; but, with a slight blow, the shell divides, when the edge of the small valve rests against the inside of the produced cylindrical part of the larger one; generally about half an inch from the top of the shell: one side of the valve, before hidden, fig. 9 _a_, is then exposed, as shown in fig. 10."--_Mr. Parkinson._ Fig. 9. _a_, the beak of the upper valve; _c_, a cavity in the superior part of the shell. Fig. 10. The under part of the shell; _b_, a depression receiving the beak of the upper valve, a. Fig. 10*. The inner surface of another upper valve, having a longitudinal fissure. The species figured is the _Productus Martini_ of Mr. Sowerby. From the mountain limestone of Derbyshire; in which deposit numerous examples occur. Fig. 11. A large species of Spirifer (_Spirifer striatus_, of Sowerby), from the mountain limestone of Derbyshire. In this species the upper valve is broken away, and one of the large spiral apophyses is seen lying imbedded in the limestone with which the cavity of the shell is filled. Fig. 13, is a beautiful example of part of one of the spiral appendages of the same species. Fig. 12. "A patch of square scales of a fish from Dorsetshire."--_Mr. Parkinson._ These evidently belong to a Lepidoid fish (_Dapedius_), whose remains are common in the Lias;[63] perfect specimens are often obtained. The British Museum contains some beautiful examples of this fossil fish. [Footnote 63: Wonders of Geology, vol. ii. p. 529.] Figs. 14, & 15. A curious fossil bivalve, from the Devonian strata of the Eifel. The flat valve is shown in fig. 14; and the deep conical valve in fig. 15; _a_, tooth in the posterior margin; _b_, a part of the surface magnified, to show its cellular structure. The species is _Calceola sandalina_, of Lamarck. Fig. 16. A species of Spirifer; _a_, medial convexity of the upper valve; _b_, the triangular foramen at the beak. Fig. 17. Spirifer (_S. cuspidatus_, of Mr. Martin), from the Mountain limestone of Derbyshire. Fig. 18, represents a common appearance in certain chalk flints. Although I have examined hundreds, and some in which the form was more definite than in the specimen figured, I am not able to offer any probable suggestion as to their origin, should they be organic bodies, of which there is much doubt.