EOCENE STRATA 11^ ENGLAND, BELGIUM!, AND FRANCE. 109 



relation between all the strata below the Bracklesham Sands is 

 so clear that by general agreement they are assigned to the Lower 

 Eocene. It is otherwise with the strata above. By some geologists 

 the Bracklesham Sands are retained as a middle division, and the 

 Barton Beds as an upper division of the Eocene ; but whereas Ethe- 

 ridge has shown that out of the 543 Mollusca of the Bracklesham Beds 

 only 81 are common to the London Clay, he finds that of the 310 

 Barton Mollusca 93 are Bracklesham species — the percentage of 

 common species in one case being 11, and in the' other 30. The 

 general facies of the faunas is also much alike. It seems, therefore, 

 better to link together these two formations as an upper division of 

 the Eocene series, as was done by Alcide d'Orbigny, and to make 

 two main divisions of the Eocene, corresponding with his Suessonian 

 and Parisian series of the Paris Basin. 



In conclusion, the classification I would now propose for the 

 Eocene is shown on p. 108. 



EXPLANATION OF PLATE V. 



In section No. 1 certain well-established sections between London and Brussels 

 are given. That of Bagshot is based on the railway section at Golds- 

 worthy Hill and on the well at Chobham Place ; London, on the mean 

 of the deep-well sections ; Sundridge, on the several sections on the 

 railway at and near Chiselhurst and in Sundridge Park; E-ochester, on 

 the Upnor pit-sections ; Heme Bay, on the cliff-section between Herne 

 Bay and the Reculvers ; Cassel, near Dunkirk, and west of Brussels, on 

 sections given by the Belgian geologists. 



Section No. 2. Hampstead, on the Heath and well-sections ; Woolwich, ballast- 

 pit near Charlton and well-section on Shooter's Hill ; Richborough, pit 

 adjoining the Castle ruins ; Watten, pits on the slope and summit of the 

 hiU ; Mons-en-Pevele, various pits and well-sections ; Bracheux, pit at 

 the Butte de la Justice ; Cuise-la-Motte, various pits and sections near 

 Compiegne. 



For fuller details of these and several other sections between Orchies and 

 Beauvais see my first correlation paper in Quart. Journ. Geol. Soc. vol. xi. 

 explanation of plate, pp. 241-246. 



The dotted lines represent the probable original prolongation of the strata. 

 The continuous line gives the level of the surface at the several localities ; but 

 owing to the great disproportion between the vertical and horizontal scales, the 

 connecting hues are only ideal. 



Discussioisr. 



The Pkesident referred to the value of the Author's early papers, 

 wherein he had succeeded in bringing order out of confusion, and 

 in establishing correlations between the British Eocene strata and 

 those of Belgium and the North of Erance. He now submitted a 

 revision of some parts of that early classification, whilst supporting 

 that classification on other points. 



Mr. Whitakee's chief cause of complaint against the Author was 

 that his work had been so thorough that there was but little left 

 for one who followed him to criticize. He referred to the character 

 of the earlier writings with respect to Lower London Tertiaries in 

 the neighbourhood of London, and how, in the year 1846, there 

 appeared the first of a series of papers which swept away errors, 



