112 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



likewise sometimes bored by the Teredo, and with the structure beau- 

 tifully preserved. 



The middle bed " h " passes towards Heme Bay into a dark clayey 

 sand full of traces of vegetable matter and with a large number of 

 concretions of iron pyrites. This may possibly represent the carbo- 

 naceous and fluviatile clays of Upnor and Woolwich. The only 

 other fossils I have found in this bed were in the cliff at Bishopstone 

 ravine. They consisted of a few rare fragments of Myliohates, Eda- 

 phodon, and Chelonia, but the specimens were too small and imper- 

 fect to distinguish the species. A few fish-vertebrse and teeth of 

 Lamna also occur. 



The upper bed " c" is an argillaceous green sand without fossils. 



Although rather dissimilar in appearance, the base of these three 

 beds is nevertheless alike, consisting in each case of quartzose sands 

 and green sand. This common character becomes more apparent 

 as the beds trend towards the Reculvers, where they pass into a light 

 greenish quartzose sand easily separable from the Basement bed above, 

 but Avithout any well-marked line of separation from the Thanet 

 Sands beneath. This want of clear divisional surfaces, and the occur- 

 rence of several of the same species of shells in the two series, might 

 be considered an objection to their being thus separated. The fossils, 

 however, taken as a group, are different from those of the Thanet 

 Sands, whilst the sands are more siliceous and contain a larger pro- 

 portion of green sand and some disseminated flint-pebbles — two mi- 

 neral characters deriving some importance from their breadth and 

 constancy. 



The indistinctness of the separating surfaces is, I believe, to be 

 attributed merely to the lithological structure of the beds ; for, owing 

 to the soft and yielding nature of the Thanet Sands on which the 

 sands of the Woolwich series were deposited, the upper surface of 

 the former would be liable to be moved and stirred up by the currents 

 which brought dowu the latter, and as both must have been in the 

 state of muddy sand, an intermixture of the surfaces in contact would 

 be almost inevitable. An illustration in point is furnished in the 

 same cliff-section between the Bishopstone ravine and the Reculvers. 

 There, in one place, a drift of light brown brick-earth reposes upon 

 the Woolwich sands. The difference of age of these two deposits 

 will not be disputed, but nevertheless there is no defined line of de- 

 marcation between them, and the " Drift " appears to pass down into 

 these old Tertiary beds. 



At Richborough the division of the Thanet Sands from the Wool- 

 wich group is still less apparent. A close examination will, however, 

 show the prevailing sharp quartzose and slightly green-sand character 

 of the latter, whilst a thin seam of green sand full of the Corbula 

 Regulbiensis, and with an occasional large Cyprina, occurs precisely 

 in the position as the same fossiliferous band at Heme Bay. I have 

 recently had this view confirmed by tlie small but beautiful series of 

 fossils obtained from this bed by the Rev. James Layton of Sandwich 

 at the railway ballast-pit, adjoining Richborough Castle. They con- 

 sist of the following species : — 



