184-6.] PRESTWICH ON THE ISLE OF WIGHT TERTIARIES. 225 



Alum Bay, and of the mixture of freshwater and marine shells in 

 the so-called upper marine formation, which he considered to be of 

 estuary origin. The sands, plastic clay, and London clay, he groups 

 in one formation. 



In 1822 Professor Sedgwick* confirmed the general correctness 

 of the divisions introduced by Mr. Webster, and noticed that in stra- 

 tum "c?" the fossils rather resembled those of the Bognor rocks than 

 those of Barton Cliff; he also found marine shells in the most north- 

 ern vertical strata of White Cliff Bay agreeing in character with 

 those of the sandy and overlying beds, which repose upon the Lon- 

 don clay at Hordwell Cliff. In this notice Professor Sedgwick gave 

 a detailed account of the nature and range of the freshwater beds 

 over the north of the Isle of Wight, and showed the mixture and 

 passage of the marine and freshwater exuvia, and the passage of 

 indurated calcareous marls into clays and argillaceous marls. 



In 1822 Dr. Mantellf noticed the great extent of the Bognor 

 rocks, described their organic remains, and gave full details of the 

 Newhaven plastic clay beds. 



In 1824 Dr. Buckland J announced the discovery by Mr. Allan of 

 the remains of the ^'' Anoplotherium commune" in the lower fresh- 

 water limestone of Binstead. 



In 1826 Mr. Lyell§ gave a detailed account of the beds underlying 

 the London clay between Muddiford and the chalk at Stutland, and 

 also of tlie beds above the London clay at Hordwell Cliff. He 

 showed the paucity of organic remains in the former, and their great 

 abundance in the latter, which he considered to belong exclusively 

 to the lower freshwater formation. 



In 1829 Mr. P. J. Martin || contributed some interesting observa- 

 tions on the anticlinal line of the London and Hampshire basins. 



In 1830 Mr. Pratt ^ discovered in the quarries of Binstead remains 

 of the PalcBotherium and of a new species of ruminant allied to 

 Moschus. 



In 1831 Professor Sedgwick** stated that he considered the anti- 

 clinal axis of the Isle of Wight to have been formed subsequently to 

 the deposition of the lower beds of the freshwater formations, a 

 portion of which he had discovered to be in vertical position in the 

 cliffs of White Cliff Bay. He considered Mr. Webster's minor 

 divisions not tenable, but the main ones he thought held good. 



In 1832-33 Mr. Lyellff coincided with these views of Professor 

 Sedgwick, and traced the probable period and duration of the anti- 

 clinal disturbance of the Isle of Wight. He concluded that it was 

 gjadual and prolonged. 



* Annals of Philosophy, vol. xix. p. 339 to 355, 



t On the Geological Structure of Sussex. 



X Annals of Philosophy, vol. xxvi. p. 360. 



§ Trans. Geol. Soc. 2nd Series, vol. ii. part ii. p. 279 to 285. 



II Philosophical Magazine and Annals of Pliilosophy, 1829. 



^ Proceedings Geol. Soc. vol. i. p. 239. 



** Ihid. vol. i. pp. 289 and 29 1. 



ft Principles of Gcologv, Art. Eocene strata. 



<i 2 



