66 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [DoC. 4, 



Introduction. — We are indebted to Mr. Prestwich for a clear con- 

 ception of the age of the Bracklesham series, and of its place among 

 the Eocene Tertiaries ; while the late Mr. Dixon has described the 

 fossils of Bracklesham and Selsea, and given a very interesting 

 account of the coast of that part of Sussex. In the course, however, 

 of collecting specimens from these beds during the last eight years, 

 I have been led to think that there are many points of interest on 

 which a more minute description of the succession of their subordi- 

 nate divisions, and of the fossiliferous localities, might be acceptable. 



The term " Bracklesham Beds" is applied to the group of strata, 

 many of them rich in organic remains, the greater part of which are 

 seen displayed at low water upon the shore of Bracklesham Bay in 

 Sussex. But I shall include under that name beds that are above 

 any seen at Bracklesham Bay, because, when the deposits of Stub- 

 bington and of the New Eorest come to be described, it will appear 

 that many of the fossil forms peculiar to the Bracklesham Beds 

 range higher than the highest stratum seen at the Bay. In other 

 words, I shall group certain strata, which appear to intervene 

 between the base of the Barton series and the highest beds of 

 Bracklesham Bay, among the Bracklesham Beds, on account of their 

 containing an assemblage of fossils more akin to the fauna of the 

 latter than of the former. 



As regards the inferior limit, I have not seen anywhere any marine 

 fossiliferous beds below the lowest at Bracklesham Bay until we 

 reach the Bognor Eock or the London Clay, except it be in a thin 

 stratum of clay at the very base of the Bracklesham series at White 

 Cliif Bay. 



Many species, as is well known, range uninterruptedly from the 

 Bracklesham Beds into the "High Cliff Sand" (by which term I do 

 not intend the sands at the base of High Cliff, but those about its 

 middle portion, so long known for the richness of their fossil-beds), 

 and a considerable proportion into the still higher beds of Barton 

 Cliff. (See fig. 2, p. ST.) For the purposes of this paper I shall 

 follow Mr. Prestwich in considering the High Cliff Sand as a part 

 of the Barton series *. 



The Carclita planicosta, Pecten cornetis, Sanguinolaria HoUowaysii, 

 Solen ohliquus, Cythe^ea suberycmoides, Voluta cithara, and Turri- 

 tella sulcifera range throughout the group, and seem to be confined 

 to it, with the single exception that Pecten corneus is rarely met with 

 in the High Cliff beds. There are certain species which have a 

 much more confined range tj and by means of these I have divided 



* Quart. Joum. G^eol. Soc. vol. v. p. 44. 



t The genus Pleuroioma affords great help in subdividing the beds, as Dr. 

 Wright and others have remarked of the Ammonites in the Mesozoic rocks. 

 With a few exceptions, the range of the various species seems very confined. 

 Pleuroioma plebeia has a very extended range, even throughout the Eocene 

 period. Pleuroioma jprisca ranges throughout a great portion of the Bracklesham 

 and Earton beds. These are the chief exceptions. The great abundance of the 

 individuals generally adds to the value of this genus in correlating beds ; while 

 the complete Monograph of Mr. Edwards renders their determination com- 

 paratively easy. 



