234 Reports and Proceedings — 



francs, wliile the two next will be given medals of silver and bronze 

 of similar shape.^ 



Geological Society of London. 



L— Marcb 23, 1881.— Robert Etheridge, Esq., F.R.S., President, 

 in the Chair. — The following communications were read : — 



1. " The Upper Greensands and Chloritic Marl of the Isle of 

 Wight." By C. Parkinson, Esq., F.G.S. 



In this paper the author described the Upper Greensand as ex- 

 posed at St. Lawrence and along the Undercliff. At the base of the 

 St. Lawrence cliff there are hard bands of blue chert, from which 

 astaciform Crustacea have been obtained ; and quite recently, in 

 a large boulder of the same material lying on the beach, there were 

 found the remains of a Chelonian, referred by Prof. Owen to the 

 family Paludinosa, and named by him Plastremys lata. The 

 presence of these freshwater organisms was thought to imply 

 a connexion with the Wealden continent. The chert-bed, 2 feet 

 thick, was regarded by the author as marking the boundary between 

 the Gault and the Greensand. Above it the author described 

 56 feet of compact red and yellow sands, of which the first 

 20 feet are un-fossiliferous, the upper 32 feet show traces of organic 

 remains ; between them there is a fossiliferous zone 4 feet in 

 thickness, containing Ammonites infiatus, A. aiiritus, and species 

 of Panopcea, CucullcBa, Area, and Trigonia, and immediately below 

 this a separate band containing an undetermined species of Ammonite. 

 These sands are followed by 38 feet of alternate beds of hard chert 

 and coarse greensands, having at the bottom 6 feet of inferior 

 building-stone, surmounted by 5 feet of fx'eestone. The latter con- 

 tains Ammonites rostratiis, and the cherts various fossils, chiefly 

 bivalves. Clathraria Lyelli also occurs at this level. Above the 

 greensands come 6 feet of chloritic marl : — the upper 3^ feet 

 fossiliferous, with a base of hard phosphatic nodules containing 

 crushed specimens of Pecten asper ; the lower 2-| feet compact, with 

 darker grains and few fossils. The author compared the sections of 

 this series given by Capt. Ibbetson and Dr. Barrois ; his own views 

 closely correspond with those of the latter writer, 



2. " On the Flow of an Ice-sheet, and its Connexion with Glacial 

 Phenomena." By Clement Eeid, Esq., F.G.S. 



The author considers that the Boulder-clays have been formed 

 beneath an ice-sheet, and consequently there must have been 

 formerly a huge mass of ice, which would have to flow 500 miles 

 on a nearly level surface, and then to ascend a gentle slope for nearly 

 another 100 miles. He does not think a great piling up of the ice 

 at the north pole can be assumed to account for this motion. This 

 he explains by the gradual passage of the earth's heat through the 

 mass of ice, raising the temperature of the whole instead of lique- 

 fying the surface -layer. As the heat passes upwards, it raises the 



' This last paragraph we extract from an article in " Nature," March 31st, 1881, 

 by Mr. De Eance. 



