224 Notices of Memoirs — 



wichii, Morris. Thus the palaeontological relations are as strong 

 between the sands of Bracheux and Thanet as between these and 

 the Lower Landenien — a fact which is further attested by the lists 

 of determined species given by Mr. Prestwich in 1852, and com- 

 pleted by Mr. Whitaker in 1866, and which are not found in beds 

 higher than the Woolmch series. 



2. (a). The Woolwich beds, Lignites of Soissons, and the Upper 

 Landenien. 



The identity of the fauna of the Lignites of Soissons and the 

 Woolwich beds is complete, for in the Paris basin the fauna of the 

 lignites has little relation with that of the Bracheux sands, or even 

 with that of Joncher}^ its nearest representative. 



Mr. Whitaker cites (Quart. Journ. Geol. Soc. 1866, vol. xxii. 

 p. 404) the following species as common to the Thanet sands and 

 those of Woolwich : — Corbida Arnouldi, Nyst, CucuUcea crassatina, 

 Lam., Cyprina Morrisii, Sby., Cytherea orhiculaiHs, Edw., Glycimeris 

 rutupiensis, Morr., Nucula fragilis, Desh., Ostrea Bellovacina, Lam., 

 Pectunculus terebratularis, Lam., Psammobia Edwm-dsn, Morr., Thracia 

 oblata, Sby. Two of these species are peculiar to the Woolwich 

 series ; others range higher, even to the London Clay ; and some are 

 characteristic of the Bracheux sands. Thus, from the succession 

 of the mineral characters, which is the same in the two basins of 

 England and France, from the identity of the faunas, and the 

 relations which unite these faunas in England, we are acquainted 

 with the complete succession of the phenomena, and there is no 

 possibility of intercalating between the Bracheux sands and the 

 lignites a deposit of a different nature, such as the Eilly limestone, 

 notwithstanding the occurrence of a certain number of freshwater 

 fossils common to the fauna of this limestone and that of Jonchery. 

 The relations between the sands of Bracheux and the lignites is still 

 more close in Belgium, so that Dumont has comprised them both in 

 his Systeme Landenien. The Upper Landenien corresponds to the 

 lignites of Soissons, for we there find the lignite beds and the princi- 

 pal fossils of this fauna. 



2. (&). The Clays of Ypres or Lower Ypresien. — London Clay. — Lacuna 

 in the Paris Basin. — Emergence.— Oldhaven Beds. 



In Belgium the beds with Cyrena cuneiformis are directly covered 

 by the Clay of Ypres, above which occur the glauconiferous sands 

 with Nummidites planidatus, Turritella edita, and T. hybrida, and 

 other fossils charaeteristic of the sands of Cuise. This clay, which 

 is the j)erfect representative of the London Clay of England, is 

 wanting in France, so that, as suggested b}"^ Dumont,' the French area 

 was probably emerged during the formation of the Clays of Ypres 

 and London. M. Hebert believes there are proofs of this emergence, 

 and cites a pebble-bed at Vignolles, between the lignites and the 

 Mercin sands, similar to those of Cuise, as a proof of an interruption 

 in the deposition, or a lacuna ; these pebbles having been produced 



1 Bull, de I'Acad. Roy. de Bel^ique, t. xix. 



