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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



exceedingly scarce in the London Tertiaries. Thirdly, the structure 

 of the Lower Tertiary sands is much more regular and uniform, and 

 they are not, like these beds, broken up and disturbed in a way which 

 seems to have arisen from the irregularity of the bed of the under- 

 lying chalk, both prior to their formation and by an increase in 

 that irregularity at a subsequent period by the action of water wearing 

 pipes. And fourthly, because I find similar beds on the chalk-downs 

 on the opposite side of the Channel, between Calais and Boulogne ; 

 and thence, passing across the plain of French Flanders, we again 

 meet with analogous strata, — though more important and with more 

 ironstone, — on the top of Cassell Hill, 515 feet above the sea, and over- 

 lying the Calcaire grossier series. No fossils are found there ; but 

 M. Dumont and Sir C. Lyell refer those beds to the Diestian Sands, 

 which they class with our Crag ; for M. Dumont had found near 

 Louvain these same sands overlying the Limburg and Bolderburg 

 strata and containing impressions of shells, of which the following 

 species are mentioned by Sir C. Lyell : — Terebratula grandis, Solen 

 Ensis, and Syndosmya prismatica; and 13 genera, of which the 

 species could not be determined, are enumerated*. 



From the apparent identity of the more important outliers of 

 yellow sands, loams, and iron-sandstones at various places on the 

 North Downs, with the small isolated fragmentary beds at Lenham 

 and Harrietsham, and from the circumstance that, when even such 

 outliers f are wanting, it is common, nevertheless, to find portions of 

 similar sands and pebbles in the core of the pipes dotted over the 

 high chalk-surface, thus showing the former wide extension of the 

 beds, I conclude that they all belong to the same series, and also that 

 they extended formerly for some distance beyond the summit of the 

 Chalk Downs, and that they are all of the same Pliocene age. Hitherto 

 no trace of any Crag has been found south of the Thames J ; the 

 occurrence, therefore, of these beds in Kent, not only so far from the 

 main mass, but also at altitudes so far exceeding any which it attains 

 in Suffolk and Essex, is a matter of considerable interest, — an interest 

 further increased by the circumstance that it gives us a still nearer 

 date whereby to limit the denudation of the Weald ; whilst, from 

 this rise in their level, and the fact of their stretching thus far inland, 

 it is probable that they may formerly have ranged over the Wealden 

 area, and even have been connected with the beds of that age in 

 Normandy and Brittany §. 



* Quart. Journ. Geol. Soc. vol. viii. p. 295. 



f The ironstones which form a marked feature in Belgium and East Kent seem 

 further westward to be of merely local occurrence. 



t My friend Mr. John Brown, of Stanway, considers some sands at Chislet, 

 between Canterbury and the Reculvers, to belong to the Crag. I cannot agree 

 with him, as I believe them to be identical with the beds beneath the London 

 Clay at Heme Bay ; but I mention the fact in order to direct the attention of 

 others to the point in dispute, and to state that, in case Mr. Brown's view should 

 prove correct, his observations at Chislet should have the priority over mine at 

 Paddlesworth and Lenham. Amongst the fossils which he has collected in that 

 locality there are some which he considers to be Crag species, whilst others are 

 distinctly Eocene, such as the Cyprina Morrisii, and others. 



§ It furnishes us also with an important clue to the age of some of the drift- 

 beds on the south of the Thames. 



