90 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Part II.* — The Paris Group (^continued). 



§ 1 . The Bracklesham Sands and Calcaire grossier ; general features 

 and shells common to the two deposits. 



In my paper of June 1854 I expressed an opinion that the lower 

 members of the Sables Inferieurs of France, — the Landenian and 

 Lower Ypresian Systems of Belgium, — and the Thanet Sands, Wool- 

 wich series, and London Clay of England, formed a natural and well- 

 marked geological division of the Eocene Tertiaries, to which, as their 

 development is most complete in this country, I proposed the term 

 of the ''London Tertiary Group." 



Above this group commences a new order of things ; the rich fauna 

 of the Calcaire grossier extends over the French, Belgian, and En- 

 glish areas, accompanied by a profuse exhibition of nummulites — a 

 feature the more marked from the absence of these Foraminifera in 

 the underlying London Group. For this next overlying series I have 

 proposed the name of the " Paris Tertiary Group" f . 



The commencement of the Paris Group is in England represented 

 by the unfossiliferous Lower Bagshot Sands ;|;, in Belgium by the 

 partially fossiliferous Upper Ypresian System, and in France by the 

 nummulite-bearing Lits coquilliers and associated sands of M. 

 D'Archiac, or the Glauconie moyenne of M. Graves. With the evi- 

 dence bearing on the synchronism of these beds I concluded my 

 former paper, and I now propose to consider the exact correlation 

 we should assign to the Bracklesham Sands and to the Barton Clay. 



It so happens that where the Bracklesham series is well exposed 

 and easily accessible, as at Alum Bay and in the opposite Hampshire 

 Cliffs, it contains no organic remains, with the exception of the perish- 

 able impressions of shells in the soft sandy strata near Christchurch. 

 In the cliffs at White Cliff Bay, — where, on the contrary, the strata 

 are in parts very fossiliferous, — the beds are much masked by the 

 falling of the cliffs, and their separation from the Barton Clays is not 

 so well seen as at the former places ; and, excepting a few leading 

 species, the fossils have not been worked out with that care and atten- 

 tion which have been bestowed on them at Bracklesham. At this 

 latter place, however, no superposition is visible. The beds crop out 

 below high-water mark in the open cliffless bay for the distance of 

 above two miles ; and the fossils have to be picked up or dug out, 

 when, after favourable conditions of wind and tide, the surface of the 



* For Part I., see Quart. Journ. Geol. Soc. vol. xi. p. 206, &c. ; where will also 

 be found a section (pi. 8) partially exhibiting the range of some of these divi- 

 sions. I have there used the old term ** Gres de Beauchamp " instead of " Sables 

 moyens." 



t Its upper limits I leave as a matter of future inquiry. 



X I had applied the term of the Lower Bracklesham Sands to the 100 feet of 

 yellow unfossiliferous sands (No. 5 of my White Cliff Bay section, Quart. Journ. 

 Feb. 1846) overlying the London Clay in the Isle of Wight; and I took them 

 then, as I still do, to be the equivalent of the Lower Bagshot Sands. I think, 

 however, it will be more convenient to confine the term of the Bracklesham 

 series to the overlying fossiliferous strata, and only to call the lower unfossili- 

 ferous sands the LoAver Bagshot Sands. 



