1852.] PRESTWICH ON THE THANET SANDS. 247 



such traces between Tweedale and Gillingham ; and at the ballast-pits 

 at Erith* the casts of bivalve shells are occasionally found. Mr. 

 Morris states that the cast of the Pholadomya has been met with in 

 the lower sands at Woolwich. Mr. Taylor confirms this fact, inas- 

 much as he has found impressions of shells in the sands at the large 

 ballast-pit near the Charlton station, and amongst them an indisputable 

 cast of a Pholadomya. In the various sections of these sands which 

 I have examined in Essex, I have never been able to find any organic 

 remains. 



There are, however, some very curious oviform bodies occasionally 

 met with in considerable abundance in the lower part of the Thanet 

 Sands. I first noticed them in Pegwell Bay, and afterwards at Shot- 

 tenden Hill ; more recently I have found them in still greater quanti- 

 ties at Bexleyf , and in a pit one mile nearly due W. from West Tilbury 

 Church. They form short quill-like tubes, consisting of an aggre- 

 gation of egg-shaped bodies about the size of cress-seed (see PI. XVI. 

 fig. 11). There is no organic structure visible, but this is apparently 

 owing to the organic matter being removed and replaced by an infil- 

 tration of argillaceous matter from the surrounding matrix. Is it 

 possible that these bodies may be the eggs of Gasteropodous Mol- 

 luscs ? 



Throughout Kent the traces of vegetables in a very fragmentary 

 state are not uncommon. They are generally mere small indistinct 

 impressions in the soft sand, or sometimes equally indistinct frag- 

 ments of carbonaceous matter, but they never occur in the connected 

 form and to the extent which they do in the overlying group. At 

 Grays and Woolwich long tubular fucoidal-looking casts are not un- 

 common ; and east of Heme Bay the large flat tabular masses of 

 calcareous sandstone are often covered with long vermiform impres- 

 sions and casts, apparently of Fuci or of spongiform bodies. 



In the determination of the species of Molluscs in the accompany- 

 ing list, Mr. Edwards and Mr. Morris have been so good as to assist, 

 and the latter to undertake the description of the new species. 

 I give columns of the three principal fossiliferous localities, but, as 

 before mentioned, there are other localities in which many of the 

 species are found. To Mr. T. Rupert Jones I am indebted for an 

 examination of several specimens of the Thanet Sands for Forami- 

 nifera. He found them only in a few specimens, and then but rarely J. 

 The chief locality where they occur is Pegwell Bay. 



At Richborough small bones and scales of fishes occasionally occur, 

 but I could not meet with any specimen sufiiciently perfect to deter- 

 mine the species. Teeth of the Lamna are also found in several places. 



is not very perfect, some portion of the shell heing generally wanting. Very beauti- 

 ful casts, in clear transparent quartz, of a very small Corbula, are, however, perfect 

 in form and very abundant. Sponge spicula are also abundant.— May 1852. 



* Mr. Morris informs me that teeth of the Shark have been found in the Thanet 

 Sands at Erith. I have just found there a large Cyprina. — [July 1852.] 



t In the lane leading towards Dartford Heath. 



X Mr. Jones has also been enal)led to add to my list a few Foraminifera and one 

 Entomostracan, that he had previously collected from the Thanet Sands of Peg- 

 well Bay. 



