Geological Society. 385 



3. "High-Level Glacial Gravels, Gloppa, Cyrn-y-bwch, near 

 Oswestry." By A. C. Nicholson, Esq. Communicated by W. 

 Shone, Esq., E.G.S. 



These gravels are found at Gloppa, and are situated at a height 

 of from 900 to 1160 feet above sea-level, on the eastern slope of a 

 ridge of Millstone Grit which forms the western border of the 

 Cheshire and Shropshire plain. 



The beds present the appearance of having been abruptly cut off 

 on the north-eastern slope. The gravels are in places much contorted, 

 and false-bedding is frequent. They contain numerous striated 

 erratics. Amongst the boulders are Silurian grits and argillites, 

 granites like those of Eskdale, Criffel, &c, Carboniferous rocks, Lias 

 shale, and Chalk flints. The shells are often broken, rolled, and 

 striated, but the bulk of them are in fairly good condition. 



A list of the shells is given, including nine Arctic and Scandina- 

 vian forms not now living in British Seas, nine northern types, also 

 found in British seas, two southern types, and nearly fifty species 

 of ordinary British forms. Comparative lists of the shells of Moel 

 Tryfan and of those now living in Liverpool Bay are placed side by 

 side with the list of shells from Gloppa. 



December 23.— W. EL Hudleston, Esq., M.A., E.B.S., 



Vice-President, in the Chair. 



The following communications were read : — 



1. " On Part of the Pelvis of Polacanihus" By E. Lydekker, 

 Esq., B.A., E.G.S. 



2. "On the Gravels on the South of the Thames from Guildford 

 to Newbury/' By Horace W. Monckton, Esq., E.G.S. 



The author stated that the greater part of the hill-gravel in the 

 district referred to belonged to the Southern Drift of Prof. Prestwich, 

 and that the valley-gravels for the most part consisted of material 

 derived from the Southern Drift. Small patches of Westleton Shingle 

 and Glacial Gravel occurred near Beading and Twyford. 



He divided the Southern Drift into three classes : — 



1. Upper Hale type, characterized by the abundance of small 

 quartz pebbles and the scarcity of chert. 



2. Chobham Bidges type, with abundance both of small quartz 

 pebbles and chert. 



3. Silchester type ; quartz scarce, and chert very rare or alto- 

 gether absent. 



He described the localities at which these types occurred and their 

 limits of distribution, and then referred to the Glacial Gravels of the 

 Tilehurst plateau, which he believed to have been deposited before 

 the excavation of the valley of the Thames between Beading and 

 Goring. 



The author then dealt with the valley-gravels, which he believed 

 to be mainly derived from the hill-gravels of the immediate neigh- 

 bourhood, and showed how the various types of hill-gravel had 



