182 Reports and Proceedings. 



region of "Wales and of tlie north, whicli was owing mainly to tlie absence of lime- 

 stone adapted for the formation of caves and of material for gravels. 



Prof. Eamsay argued that caves such as those in which Mammalian remains occur 

 must have existed in Pre-glacial time, and therefore that it would be strange if none 

 of those explored contained Pre-glacial remains. He was not satisfied as to the cause 

 of the Thames forming a line of demarcation marking the absence of Glacial deposits. 

 It could only be accounted for in his mind by the valley of the Thames having been 

 entirely excavated since the Glacial period, though he acknowledged this was a bold 

 speculation. He had always regarded the Thames valley deposits as Post-glacial. 



Mr. Whitaker had been brought to the conclusion that the brick-earth of the 

 Thames valley belonged to the latter part of the Post-glacial period. Beneath the 

 Corbicula beds of Erith were the remains of Pisidium and many of the common recent 

 species of the neighbourhood. He saw no such extreme difficulty in the excavation 

 of the Thames valley since the deposition of the Boulder-clay. (See Letter, p. 188.) 



Mr. J. Gwyn Jeffreys mentioned the Helix ruderata and E. fruticum as being 

 instances of shells of northern character occurring in the Thames valley at Ilford. 

 No shells of an Arctic or Boreal character occurred in the south of England, so that 

 it would appear that it had not been submerged. 



Mr. Prestwich was glad to find that the opinion of the Thames valley deposits 

 being Post-glacial was gaining ground. He called attention to the existence in 

 France of river-gravels belonging to an earlier period, such as that near Chartres, so 

 that such might exist elsewhere. He could not reconcile the occim'ence of Hippo- 

 potamus so far north as Leeds with its annual migration, as had been suggested. 



Mr. Godwin-Austen agreed with the view of the author of the " Reliquise Diluvianise," 

 that the animals whose remains occur in caves lived prior to the submergence which 

 filled the caves, or, in other words, to the Glacial period. He thought that it was 

 impossible for all the animals whose remains occurred in the river- gi-avels to have 

 occupied the land surface at the same time. He considered that English geologists 

 were too prone to argue from phenomena confined to this country. A long island 

 must have existed where now is the south of England, at the Glacial period ; and he 

 thought that at that time all animal life must have ceased there. If so, our divisions 

 of time could not apply to the continent, where no such extreme changes in conditions 

 took place. 



Mr. W. Boyd Dawkins, in reply, admitted that possibly some animals classed as 

 Post-glacial belonged also to the Glacial period ; but for convenience sake he had 

 adopted the three divisions in the paper. He saw no necessity for any of the animals 

 being of purely southern origin. He did not identify the Lower Brick-earth of the 

 Thames valley with the other river-deposits, though from the presence of the Musk- 

 sheep, he was inclined to place them later than at one time he did. The only reason 

 he could give for the absence of Pre-glacial caves both in England and on the con- 

 tinent was, that the rocks containing them may have been removed by denudation. 



GrEOLOGiCAL SOCIETY OF Glasgow. — I. TMs Societj met on the 

 evening of January 5th, Mr. Edward A. Wunsch, V.P., in the chair. 



The Eev, Henry W. Crosskey exhibited a small block of limestone, 

 bored by Pholas, from Great Orme's Head, which he had lately 

 visited in company with Mr. E. D. Darbishire, of Manchester. He 

 described the position and peculiarities of the sujoposed Pholas 

 borings. The specimen exhibited was from a height of 570 feet. The 

 preservation of the Pliolas burrows in the position in which they are 

 now found, proves that the elevation of the land must have taken 

 place since the Glacial epoch. 



Mr Edward Hull exhibited some specimens of pebbles from the 

 New Eed Conglomerate (Trias) of Central England, in the neigh- 

 bourhood of Burton-on-Trent. The majority of these pebbles were 

 stated to be composed of purple, pink, or " liver coloured" quartzite, 

 while a few pebbles of local origin from the Carboniferous rocks also 

 occur. The quartzite pebbles are invariably rounded and water- 



