Chalk Formation.
I.—Shanklin, or Lower Greensand. Ly. p. 219.
Dr. Fitton's Memoir, previously quoted, contains numerous figures of the characteristic shells of this division of the Chalk, particularly of the species which abound in the celebrated Whetstone of Devonshire. Geol. Trans. New Series, vol. iv. Pl. XIII-XVIII. See also Prof. E. Forbes's Catalogue of Lower Greensand Fossils, in the Quart. Geol. Journal, vol. i.
II.—Galt and Upper Greensand. Wond. p. 307; Ly. p. 218.
Inoceramus concentricus; Wond. p. 330, fig. 1.
————— sulcatus;—fig. 3.
Terebratula lyra; Ly. fig. 219.
Pecten quinquecostatus;—fig. 203.
Ostrea carinata;—fig. 204.
In Plates XI. and XII. of Dr. Fitton's Memoir, there are figures of more than twenty characteristic shells of this division of the Chalk.
III.—White Chalk. Ly. p. 211, Foss. South D., Geol. S. E.
Some cretaceous species are delineated in Lign. [125], [126], [128], [129], [130], [138]; and Sir C. Lyell figures other species; but I must refer the student to the Foss. South D., Geol. S. E., and Dixon's Fossils of Sussex, as accessible works containing numerous figures of the fossil shells of the Chalk. Accurate descriptions and representations of all the British chalk shells, however, are still much required. Mr. Davidson has done much towards the illustration of our Cretaceous Brachiopods; and the shells of the Cretaceous strata of the United States are figured and described in an elegant work by Dr. Morton, of Philadelphia.
Tertiary Formations.