278 SUBMERGED ROCK- VALLEYS IN SOUTH WALES, ETC. [Aug. 1 898, 



cases, however, the Glacial deposits are devoid of mammalian 

 remains which occur in the lower Pleistocene gravels in various 

 localities of the same area. On the other hand, the stream-tin 

 deposits contain such remains, and also give the same evidence of 

 depression as do the deposits described in the paper. For these 

 reasons, these deposits appeared to him to be post-Glacial. 



Mr. J. E. Clark called attention to two important points which 

 the paper seemed to establish. The submergence in the South-west 

 exceeded that in the South-east, exactly as had been shown between 

 North-western and North-eastern England, and again in Western 

 and Eastern Scotland. The deepl)' submerged peats and tree-stools 

 indicated, again as in the North, that the post-Glacial recovery 

 brought the land-level almost to normal pre-Glacial conditions. 

 But its brief duration was strikingly shown by the York Central 

 Plain. If the Glacial beds were stripped away, there would now be 

 a vast inland sea, hundreds of square miles in extent, reaching 

 beyond York, whereas the post-Glacial Ouse had only time to cut 

 a narrow, 70 feet deep, gorge through the present site of the 

 city. 



Mr. Lamplugh commented on the steep trough-like character of 

 these old valleys in every part of the country, and on the fact that 

 they often occur within broad and shallow depressions of higher 

 antiquity. They were evidently due to an elevation of comparative 

 rapidity and of short duration, so that the streams had never reached 

 their new base-level of erosion. Hence they did not register the 

 full amount of the elevation. 



Mr. Clement Eeie and Prof. W. W. Watts also spoke. 



The Author, in reply, said that the Boulder Clay in the Neath 

 bridge-foundations was no longer visible, but the deposits close by 

 were still to be seen. The contained rocks appeared to be from the 

 high ground not far off. Most of the points raised in the discussion 

 were dealt with in the paper, for the favourable reception of which 

 he thanked the Fellows. 



