This bed consists of a soft, whitish, tenacious clay, which, when immersed in water, is found to be largely composed of minute grains, that prove to be foraminifera. These shells belong to many species and genera; and are associated with the cases of entomostraceous crustaceans, spicula of sponges, &c. The organisms readily separate from the amorphous particles by washing, and specimens may be easily obtained as distinct and perfect as if recent. See _Lign. 109_, _ante_, p. 342. Intermingled with the cretaceous forms, are minute fresh-water shells, apparently derived from a modern source. The Charing deposit appears to have originated from the action of water on the unconsolidated chalk of the neighbouring Downs, before the surface of the hills was protected by a covering of vegetable soil. Through the liberality of Mr. Harris, I have been able to examine an extensive series of the Charing Foraminifera; and Prof Williamson has figured and described the principal types in an interesting memoir in the Transactions of the Manchester Philos. Soc. vol. viii. 1847. As in most of the cretaceous strata, the prevailing species are referable to the genera Textularia, Rotalia, Rosalina, Cristellaria, Lagena,[332] &c. There are numerous spicula of sponges, and needle-like calcareous prisms, which are the detritus of the fibrous shells, called Inoceramus. [332] This interesting type of Foraminifera is the subject of a Memoir by Prof. Williamson; Annals, Nat. Hist. 1848, vol. i. Foraminifera of the Oolite, Lias, &c.--The occurrence of certain genera in particular rocks has been incidentally noticed in the previous descriptions, and it is needless to particularize any localities of the Oolite, Lias, and other secondary deposits. It must suffice to state that Dr. Carpenter, Prof Williamson, Prof Phillips, Mr. Sorby, Mr. Rupert Jones, and other able observers, have figured and described foraminifera from the strata between the Chalk and the Carboniferous formations: the report to be drawn up by the two first-named gentlemen for the British Association, will present a resume of the British fossil genera and species. It is deserving record, that no vestiges of foraminifera have been found in the Wealden strata; the fluviatile origin of those deposits renders it improbable that the remains of these marine organisms should occur in great numbers, yet from, the estuary character of some of the beds, the presence of foraminifera might be expected.