1847.] 



PRESTWICH ON THE LONDON CLAY. 



373 



Table showing the range of the Fossils given in the foregoing lists 

 into other 'parts of the Eocene series of London and Hampshire, 



Localities. 



Number of 

 identified 

 and de- 

 scribed spe- 

 cies found 

 at each 

 locality. 



Isle of Wight , 



Southampton 



Clarendon Hill 



Cuffell and Clewett's Green 

 Newnham and Old Basing.. 



37 

 33 

 23 

 51 

 43 



Species 



common to 



Highgate 



or Hamp- 



stead. 



Species 



common to 



Bognor*. 



29 

 24 

 16 

 39 

 30 



Species 



common to 



Brackle- 



sham. 



19 

 17 

 14 

 24 

 21 



Species 



common to 



Barton. 



14 

 12 

 11 



18 

 19 



13 

 12 

 11 

 16 

 19 



From this examination it appears that the per-centage of species com- 

 mon in each locahty to Highgate, Hamp stead and Bognor is far greater 

 than to Bracklesham and Barton f, and that the Highgate and Hamp- 

 stead forms exist in nearly as large a proportion in these strata in 

 Hampshire as they do in the western portion of the London district. 



It is therefore fair to assume, both from strict analogy of structure 

 and a near similarity of organic remains, that the London clay is 

 represented in Hampshire by the lowest fossiliferous beds, which in 

 my last paper I had termed the Bognor beds, and that consequently 

 it is older than the Bracklesham beds, and still older than the Barton 

 beds. I should also propose that the term Jjondon clay be applied 

 and restricted to this its equivalent in Hampshire instead of the term 

 of Bognor beds, as being the better-known designation, and the more 

 important section of this formation (see table at end, and Plate XIV. 

 Comp. Sect.). 



I have previously stated I the probability that the Bognor beds are 

 at or near the base of the London clay ; but the same genera which at 

 Bognor form a distinct and typical group, associated within narrow 

 vertical limits, are found in the Isle of Wight in greater dispersion 

 and isolation through a vertical range of 200 to 300 feet. (Strata 3 

 to 6 of Alum Bay, and 3 and 4 of White-Cliif Bay— see Plate XIV. 

 Comp. Sections, figs. 2 and 3.) At Highgate, and elsewhere in the 

 neighbourhood of London, we find the Bognor group of fossils chiefly 

 congregated in great abundance at the base of the London clay. I 



* The number of species found at Bognor amounts at present to about 32. 



t I believe it likely that the proportion of species common to London, Barton 

 and Bracklesham will be materially reduced as our knowledge of the Highgate, 

 Hampstead and Sheppey forms extends. In the fine collection of Mr. Wetherell of 

 Highgate, many of the numerous undescribed species from Highgate and the 

 neighbourhood are of common and characteristic forms. If these were added to 

 the list of London clay species, we should probably find, as at Newnham and in 

 Hampshire, that the London clay of Highgate would exhibit a larger proportion 

 of Testacea peculiar to it. The large work upon which Mr. Dixon of Worthing 

 is engaged will also, I hope, shortly make known a more complete Hst of the 

 organic remains from the productive locality of Bracklesham Bay, and also of 

 those of Bognor. 



X Journal of the Geol. Soc. for August 1846, page 236. 



