354 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 26, 



1. On the probable Age of the London Clay, and its Relations to 

 the Hampshire and Paris Tertiary Systems. By J. Prestwich, 

 Juii., Esq., F.G.S. &c. 



It is not intended on the present occasion to enter generally upon 

 the subject* of the London clay, nor yet to describe its structure 

 and fauna further than may be necessary to prove the argument of 

 this paper, which is, that the London clay of Highgate, Sheppey, and 

 other places in the neighbourhood of London, apparently is not, as it 

 has hitherto been considered, synchronous with the Calcaire grossier 

 of Paris, nor yet with the clays of Barton, and the clays and sands of 

 Bracklesham ; but that it is of older date than these, and consequently 

 occupies a lower position in the Eocene series. 



* For previous descriptions (Mr. Webster's especially) of the Hampshire Ter- 

 tiaries, see my paper in the Journal of the Society for August 1846, pp. 224 to 226. 

 Since then Mr. Searles Wood has contributed some important information to our 

 knowledge of Hordwell Cliff. His list of the organic remains from its freshwater 

 and fluvio-marine strata is far more complete than my own. 



The following are the additional species given by Mr. Wood : — 



Marine Beds. 



Aeteon. Cytherea obliqua, Desk, 



Area elegans, S. Wood, MS> Cytherina. 



Csecum. Gastrochsena. 



Cancellaria muricata, S. Wood, MS. Lucina pulvinata, S. Wood, MS. 



elongata, S. Wood, MS. Melania angulata, S. Wood, MS. 



Cardium. muricata, S. Wood, MS. 



Cerithium terebrale, S. Wood, MS. Melanopsis minuta, S. Wood, MS. 



Chemnitzia, 2 species. Natica epiglottina, Lam. 



Cristellaria. Odostomia subulata, S. Wood, MS. 

 Cyrena cycladiformis, Desk. 



Freshwater Beds. 



Cyclas exigua, S. Wood, MS, Melania circincta ?, Lea. 



Cyrena obliquata, Desh, Paludina unicolor, Swainson. 



pisum, Desh. ■ ? impurata, S. Wood, MS. 



Dreissena Brardii, Faujas. Planorbis hemistoma ?, Sow. 



Helix labyrinthicus, Sar/. planulatus, Desh. 



striatella, Anthony. platystoma, S. Wood, MS. 



Lymnea strigosa, Brong. Potomomya subangulata, Sow. 



elodes, Say. Potamides funatum, Sow. 



Melania carinata, ^S*. Wood, MS. Succinea imperspicua, S. Wood, MS. 



subulaspira, S. Wood, MS. 



Besides these, Mr. Wood found a magnificent lower jaw of an Alligator, for which 

 he proposes the specific name of Hantoniensis ; also remains of the following Ver- 

 tebrata — Dichobune, Palaotherium, Seal, Lepidosteus Jimbriatus, S.Wood, — two 

 new genera, for which he proposes the names of Microchmrus erinaceus and Spa- 

 lacodon, and a Rodent allied to Anomalurus and Sciurus. (See Charlesworth's 

 London Geol. Journal, Nos. 1 and 3, 1846-47.) 



To the Marchioness of Hastings we are also indebted for some valuable palseon- 

 tological discoveries in the freshwater beds of Hordwell Cliff, including a new 

 species of extinct Pachyderm, which Prof. Owen has named Paloplotherium, aud 

 a Crocodile, named by Prof. Owen Crocodilus Hastingsii. (See Report of the Meet- 

 ing of the Brit. Assoc, for 1847, in the ' Athenaeum' of the 3rd of July.) 



These further observations confirm the views expressed in my last paper, that 

 these strata are not the equivalents of the freshwater formations of Paris, but are 

 yather of the age of the Upper Calcaire grossier. The evidence however is yet far 

 from being sufficiently positive. — September 1847. 



