376 Reports and Proceedings — 



1. They were all composed of one rock, and that invariably a rock 

 to be found in place close by. 



2. Any denudation which could have removed the clay and 

 smaller stones of the drift would have obliterated the traces of 

 glaciation on the surface of the rock. 



3. The boulder which had protected the fine glacial markings 

 below it from the action of the rains would certainly in some cases 

 have preserved a portion of the stiff Boulder-clay. 



4. The margin of the Boulder-clay along the flanks of Ingle- 

 borough was generally marked by lines of swallow-holes, into 

 which the water ran off the Boulder-clay ; and when the impervious 

 beds overlying the limestone had been cut back by denudation, a 

 number of lines of swallow-holes marked the successive stages in 

 the process ; but there was not such evidence of the former extension 

 of the drift up to the Norber boulders. 



5. The boulders themselves were not rounded and glaciated in the 

 same way as the masses of the same rock in the drift, but resembled 

 the pieces now seen broken out by weathering along the outcrop of 

 the rock close by. 



Having thus shown the improbability of these boulders having 

 been let down out of a mass of drift the finer part of which had 

 been removed by denudation, or of their having been masses floated 

 to their present position on shore-ice, he offered an explanation of 

 their peculiar position, which he thought was not inconsistent with 

 the view that they belong to some part of the age of land-ice. 



That they were to be referred to some exceptional local circum- 

 stances seemed clear from the rarity of such glaciated pedestals, 

 while boulders and other traces of glaciation were universal over 

 that part of the country. He therefore pointed out in explanation, 

 that they occurred always where there was a great obstacle in the 

 path of the ice: — at Cunswick the mass of Kendal Fell curving 

 round at the south and across the path of the ice ; at Farleton the 

 great limestone escarpment rising abruptly from Crooklands ; at 

 Norber the constriction of the Crummack valley near Wharfe and the 

 great mass of Austwich grit running obliquely across its mouth. In 

 all these cases the ice had to force its way up hill ; and there would 

 be a time when it would just surmount the obstacle after a season of 

 greater snowfall, and fall back after warm seasons, until it fell back 

 altogether from that part. During the season of recession, boulders 

 would be detached below the ice-foot ; during the seasons of advance 

 they would be pushed forward ; and in those exceptional localities 

 of isolated hills from which the drainage from higher ground was 

 cut off, the boulders were left on a clean furrowed surface of lime- 

 stone, which was then acted upon by rain-water and the vegetation, 

 except where protected by the boulders. 



2. " On some Derived Fragments in the Longmynd and Newer 

 Archaean Eocks of Shropshire." By Dr. Charles Callaway, F.G.S. 



Further evidence was added to that given in the author's previous 

 paper (Q.J.G-.S. 1879, p. 661), to show that the Longmynd rocks 

 of Shropshire were chiefly composed of materials derived from the 



