XXIII. On the fossil remains of the soft parts of, discovered in the chalk and flint of the South-East of England

Abstract

The last communication I had the honour to lay before the Royal Society, related to the organic remains of the colossal extinct Reptiles, which inhabited the dry land, during that remote period when the Wealden strata were deposited. The present notice embraces the consideration of the fossil relics of beings so minute as to be invisible to the unassisted eye, that swarmed in the cretaceous ocean, and of which numeious genera and species have descended through succeeding ages, and constitute a large proportion of the inhabitants of the present seas. In a microscopical examination of chalk and flint, undertaken for the purpose of testing the accuracy of the statement of M, Ehrenberg, that a considerable portion of the cretaceous strata is composed of minute organisms, I observed that the chambers of the shells of many Rotaliœ were filled with a substance, varying in appearance from a dark opaque brown, to a light transparent amber; and resembling in form, the soft bodies of existing species of Polythalamia. I was particularly struck with the similitude between some of the fossils, and the recent Nonionina when deprived of its shell by immersion in diluted hydrochloric acid; and having, by the courtesy of Mr. Williamson of Manchester, procured Rotaliæ from mud dredged up in the Levant, I found among them several that contained the body of the animal partially collapsed, and of a dark brown colour, which presented an analogous appearance. I was therefore led to infer, that the substance filling the cells of the flint Rotaliæ was the remains of the soft parts of the original animalcules, in the state of molluskite .