408 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 21, 



and Reading has been described by Mr. Prestwich*, near Pinner 

 by my colleague the late Mr. Trench, and near Reading, Amersham, 

 Chesham, and Maidenhead by myself f. 



(6) This bed, which consists of alternations of brown clay and 

 loam, is local, occurring only, I believe, east of Paversham. It may 

 be seen at Pegwell Bay, where it is separated from the Chalk by 

 little more than a foot of the base-bed. No fossils have been foand 

 in it. 



This is mostly overlain by, and passes up into, the sandy marl {d), 

 although another bed sometimes occurs between. 



(c) In the railway-cutting close to Bekesbourne Station, east of 

 Canterbury, there is a little sand below the sandy marl (d), in which 

 the greater part of the cutting is made ; and this I take to be the 

 same as the Thanet Sand of London and the western part of Kent. 

 The only other place in that neighbourhood where I saw anything 

 of it was at Selling. 



This fine light-buff, sand thickens westward, and near Sitting- 

 bourne forms a considerable part of the Thanet Beds. Further west 

 it gets still thicker, at the expense of the beds above, until, on the 

 other side of the Medway, it rep^'.aces tbem altogether, and takes up 

 the whole of the space between the Woolwich Beds and the base-bed, 

 some 60 or 70 feet. It thins slightly to the neighbourhood of 

 Woolwich, and then rather more rapidly until it dies out west of 

 London. 



No fossils, excepting some casts oiPholadomya at Erith (recorded by 

 Mr. Prestwich), have been found in this bed, which is fairly uniform 

 throughout its range. At Charlton and elsewhere its lower part is 

 more clayey, and it passes down into the base-bed. 



(d) Near and east of. Canterbury a grey sandy marl is the most 

 marked member of the Thanet Beds. It is often rather hard, con- 

 tains green grains, and is of a slate-grey colour, which weathers to 

 a sort of brownish-yellow by exposure, the division between the 

 two colours being sometimes sharp enough to mislead one into 

 thinking that there are \;Wo distinct beds. 



It often abounds in fossils ; and from it have come most of the 

 rarer specimens in the collections of my East Kent friends, such as 

 the parts of Crustacea, a few Echinoids, the Turritella, a Solarium, 

 ard other small univalves, besides many remarkable distorted speci- 

 mens of Gyprina Morrisii and P^ioladomya cuneata. In the dis- 

 coloured exposed parts the fossils are nearly all casts, the shell 

 having been dissolved away ; whilst in the less exposed part the 

 shells remain, but are very fragile. 



This division may be much thicker in some places than is shown 

 in the section (Plate XXII.) ; for Mr. Dowker found 93 feet of '' blue 



* Quart. Joiirn. Geol. Soc. vol. x. pp. 82, 87, 88, 116. 

 t aeol. ISurvey Meni. on ^heet 7, pp. 29, 37, 39, 44 ; and on Sheet 13, pp. 29, 

 37-39. 



