136 On some of the Strata in the Neighl our hood of London, 



in two feet of the surface, are divers strata of sand and 

 gravel mixed with fragments of shells, and small pebbles; 

 and it is in some of these last-mentioned strata that the fos- 

 sil shells are imbedded. These fos5.ils lie promiscuously 

 together, bivalve and turbinate, neither do the strata ia 

 which they lie observe any order, being sometimes higher 

 and sometimes lower in the cliff; with strata of sand, gravel, 

 and fragments of shells between. Nor do the shells always 

 lie separate or distinct in the strata, but are sonietiincs found 

 in lumps or masses, something friable, cemented t(>gelher 

 with sand and fragments, of a ferruginous or rusly colour, 

 of which all these strata are*." 



The coast of Essex is here separated from that of Suffolk 

 by the river Stour, by which the continuity of this stratum 

 is necessarily interrupted. It however occurs again on the 

 opposite side of the river, and through Suffolk and great 

 part of Norfolk the same bed of shells is found on digging; 

 thus appearing to extend over a tract of at least forty miles 

 in length. 



These shells are in general fotind in the same confused 

 mixture as is described by Mr. Dale ; but they are also 

 sometimes so disposed, that patches of particular genera 

 and species appear to be now occupying the very spots 

 where they had lived. This seems particularly the case with 

 the small pectens, thr mactrce, 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 acknow- 

 ledged fossil shells, however, have undergone much less 

 changes than those of this stratum ; the original coloured 

 markings are entirely discharged, and the external surfaces 

 are deeplv penetrated with a strone; ferruginous stain ; the 

 iliner surfaces also are considerably changed, their resplen- 

 dence being superseded, to a considerable depth, by a dead 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 cnly, which may be placed among those which are 

 supposed to be lost, or among those which are the inhabi- 

 tants of distant seas, arc 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. 



* Appendix by Samuel Dale to the History and Antiquities of Harwich 

 and Dovercourt by Silas TayJor, 1732. ' • 



Among 



