the case with the small pectens, the mactræ, and the left-turned whelk.
From the excellent state of preservation in which many of these shells have been found, it has been thought that they could hardly be regarded as fossil. Many acknowledged fossil shells however have undergone much less changes than those of this stratum; the coloured markings are entirely discharged, and the external surfaces are deeply penetrated with a strong ferruginous stain; the inner surfaces also are considerably changed, their resplendence being superseded, to a considerable depth, by a dead whiteness, the consequence of the decomposition of this part of the shell.
Like the fossils of most other strata this assemblage of shells manifests a peculiar distinctive character. A few shells only, which may be placed among those which are supposed to be lost, or among those which are the inhabitants of distant seas, are here discoverable; the greater number appearing not to differ specifically, as far as their altered state will allow of determining, from the recent shells of the neighbouring sea.
Among those, of which no recent analogue is known, appears to be the terebratula, figured in Dale's History and Antiquities of Harwich, &c. tab. XI. fig. 9. p. 294, and described, Phil. Trans. No. 291, p. 1578. Mr. Dale describes this shell as Concha longa fossilis fasciata, and remarks that he has not observed “ either in Aldrovandus, Rondeletius, Belonius, Gesner, Johnson, Lister, or Bonanus, any shell that resembles this our fossil, unless it is one of those figured by Lachmund, p. 43, No. 6 and 7, the inward part resembling our fossil.“ The shells figured by Lachmund are undoubtedly terebratulæ, but they manifest no particular agreement with this fossil.
This shell appears to be figured by Lister, Histor. Conchyl. tab.
