306 THE BTJNTEK PEBBLE-BEDS OF THE MIDLANDS. [May 190a, 



suggested that some of the pebbles might come from the north, 

 others from the south. Now the fossiliferous pebbles, which it 

 was urged came from the latter direction, had been found at least 

 as far north as Nottingham ; so that it was difficult to imagine 

 the river-system which would bring about such an extraordinary 

 crossing of materials. Prof. Sollas had been misinformed as to the 

 relation of size and shape in the Devon pebbles. There large and 

 small were disc-like ; both, in the Midlands, were generally egg- 

 like. He could not understand how, by any survival of the fittest, 

 the small minority, in beds not exceeding 100 feet in the one case, 

 could become the majority in beds of thrice that thickness in the 

 other. He knew the district of which Mr. Gibson had spoken, but 

 failed to see the significance of the alleged thickening of the 

 pebble-beds about the South Staffordshire Coalfield, unless Mr. Gibson 

 looked upon that as the source of the pebbles. He had seen some- 

 thing of the East Anglian gravels, mentioned by Mr. Clement Eeid, 

 but, having regard to the very different dates of the two, did not see 

 that they had much to do with the present question. The materials 

 also were very different, as were the rocks of the Ardennes region, 

 from that of the Bunter pebbles. To Prof. Watts he replied that 

 he had already been careful to point out, so long ago as 1888, 

 the difference in the action of mountain-torrents and strong streams; 

 that there was not room in the Midlands for the former, and, as he 

 had shown in his paper, no probability of the latter coming from 

 any but a northern direction. The Longmynd conglomerates were 

 inadequate as a source of the quartzite-pebbles ; the Torridonian he 

 had shown to be a quartz- rhyolite rather than a quartz-felspar grit ; 

 and the argillites were apparently absent from the Midland Bunter. 

 Its more important constituents occurred to the north ; all other 

 localities suggested were supported by hypotheses, not by facts. 



