3798 Isle of Wight Philosophical Society. 



Proceedings of the Isle of Wight Philosophical and Scientific Society. 



December 20, 1852. — Several new members were proposed for admission, to be bal- 

 loted for at the next meeting. 



Donations of numerous geological specimens were announced from C. Cramer, 

 Esq., Rev. C. U. Barry, and C. Pearson, Esq. 



Professor E. Forbes, of London, who has been for some time engaged in this loca- 

 lity upon the Geological Survey of Great Britain, exhibited some living specimens of 

 remarkable Limaces, taken in the Isle of Wight, by Mr. Gibbs, including the black 

 caricated slug {Limax Gagates), which had never been noticed but once before in 

 England. 



Professor Forbes then proceeded to give an account of the freshwater tertiary for- 

 mations of which the greater part of the northern portion of the Isle of Wight is made. 

 Hitherto it has been supposed by all geologists who have written upon the district, that 

 the well-known Headon Hill, upper and lower freshwater formation, constituted most 

 of the country to the north of the chalk range. Mr. Prestwich alone suggested that 

 the cliffs of Hempstead, near Yarmouth, were composed of higher beds. In reality, 

 however, the Headon-hill beds, properly so called, constitute but a very narrow strip 

 of the island ; and certain strata that rest upon them, including the limestones and 

 marls of Bembridge, Binstead, Cowes, Gurnet Bay, Hempstead Ledge, and Sconce, 

 form a large tract of country of an entirely different geological age, and distinguished 

 by distinct and peculiar fossil remains. These beds have hitherto been mistaken, both 

 by British and foreign geologists, for Headon-hill beds, and in most instances for beds 

 at the bottom of the Headon-hill series. Above them, lies another, and equally dis- 

 tinct, formation, of which Hempstead Hill, and probably Parkhurst, are composed. 

 The fossils in this highest group are also distinct. These upper tertiaries form a series 

 of rolls, constituting the undulated country between the eastern and western extremi- 

 ties of the island. These rolls, dependant on lateral compression, are also to be seen, 

 as lately observed by Mr. Bristow and Mr. Aveline, during the course of their 

 researches, affecting the older marine tertiaries, and the chalk itself. Altogether, there 

 is a thickness of more than 500 feet of freshwater strata, above the Headon-hill series, 

 unrecorded in works on British geology. Osborne House stands upon a formation 

 hitherto undefined, and not mentioned in geological manuals. 



Professor Forbes proposes to divide these additional groups into three series : — 1st, 

 The St. Helen's and Nettlestone beds ; 2ndly, the Bembridge beds ; and 3rdly, the 

 Hempstead-cliff beds. Full accounts of them will be published by the Geological 

 Survey of Great Britain, under the direction of Sir Henry de la Beche, who has, dur- 

 ing the last two years, been actively engaged in personally exploring and superintend- 

 ing researches in the Isle of Wight, and at whose suggestion the inquiries were made 

 which led to the discoveries now announced. An animated discussion ensued upon 

 the subject of Professor Forbes' communication. For this most interesting account, 

 as well as for his courtesy, in having made this Society (established especially for sci- 

 entific researches) the medium through which first to make a great fact public, — a 

 fact so peculiarly interesting to the island, — an unanimous and hearty expression of 

 thanks was passed to the discoverer of these new geological series. 



The Society then adjourned until Monday, .January 3, on which evening it was 

 announced that Dr. Drew would favour the Society with a paper on the causes which 

 led to the discovery of the new planets. 



