and on the Fossil Remains contained in them, 145 



made whilst the shells were in a softened state. This cir- 

 cumstance is particularly evinced in the Crjcladcs, in which 

 a partJcuiar characfei in the huige n-as thub concealed; in 

 a mass ot these shells from the "isle of Wicrht, it appears 

 that the lateral teeth are crenulated, son;e\\hat similar lo 

 those of the Mactra soliaa iu (he gravel stratum; but in 

 the Cydadei of Plumsteaci this was not discoverable, from 

 the injuries which their surKice had sustained from the sand. 

 The to-sils of this stratum evidently a^ree with those 

 found by Lamarck and M. De France abJVc the chaik at 

 Grignon, Courtagnon, &c, anil they have been just shown, 

 incidentally, to exist in the Isle of Wight. In an eastern 

 and southern direction from London ihis stratum with its 

 fossils is frequently discovered. 



On the heaih near Crayford, about four miles eastward 

 of Charlton, long vaulted oysters are found similar to those 

 already mentioned. About two miles further, in the parish 

 of Stone, is Cockle-shell- bank, so called, as Mr. Thorpe, the 

 author of Custumale Rffense, says, p. 254 of that work, 

 *' from the great number of small shells there observable." 

 These are the Cydadts already spoken of, and which Mr. 

 John Latham, author of The general Synopsis of Birds, 

 thought bore some resemblance to Tdiina cornea Linn. 

 Histor. Condiyl. of Lister, tab. 1.59, fig. 1-1. Mr. Latham 

 here also met with a species of Cerithmm, and another of 

 Turritella. Fragments of these shells are also frequently 

 turned up with The plough in that neighbourhood. They 

 have likewise been found at Dartford, at Bexley, and at 

 Bromley, to the southward. 



Mr. Thorpe also relates that in the parish of Stone there 

 was a large niass of stone, ol' some hundreds weight, full of 

 shells, which was brought from a field, and used as a brid2;e 

 or stepway over a drain in the farm-yard, [Custumale RdF- 

 fense, p. 255.) 



In several spots in the neighbourhood of Brom'ey, stone 

 is found near the surface, formed of ovster-shells still ad- 

 hering to the pebbles to which they were attaclied, and 

 which arc similar to those which have been just described 

 as occurring al Plumstead and at Charlton ; the whc^le be- 

 ing forn.ed by a calcareous cement into a coari^e shelly lirne- 

 Klone containing numerous pebbles. The only quarry of 

 this stone which has been yet worked is in the grounds of 

 plaude Scott, Esq. 'I'he opening hitiierln made i-iljut small ; 

 it is however sufficient to show that the stratum here worked 

 has suriered some degree of di;;piacenient, as it dips with an 

 angle of about forty-five degrees. 



Vol. 3.S. No. 160. Aiic-uit iBil. K At 



