372 



ME. C. EE1D OX THE 0KIGIX OF DRY CHALK 



differ from Boulder- clay ; though he thought the two deposits might 

 be connected in much the same way as gravels in the Eastern 

 Counties were the residue of Boulder-cla} T left after tidal waters 

 had washed the clay away. The clay had been swept out of the 

 Findon valley. He believed the entrance to such a valley was wide 

 in proportion to the duration of marine action upon it, and that 

 although other agencies may have since softened its features, there 

 was no ground for appealing to them to account for its origin. 



Mr. Evaxs was grateful for any new theory offering an explana- 

 tion of the Elephant-bed. He agreed as to the possibility of the 

 frozen condition of the ground, but was not prepared to go the 

 whole length of the Author. He dissented from the views of Prof. 

 Seeley. The question of the Elephant-bed was distinct from that of 

 the formation of Coombes. Its age was undoubtedly subsequent to 

 the elevation of the old submerged cliff. He considered that with 

 a certain amount of submergence, streams of water would run in 

 the now dry valleys. According to the Author's hypothesis, the 

 more impervious the condition of the Chalk the more rapid would be 

 the process of excavation. This he was prepared to accept ; but a 

 greater rainfall would have much the same effect as frost. If the 

 Chalk hills were saturated with water, the conditions would, as he 

 had elsewhere shown, be very nearly the same as if the rock were 

 frozen. Even a double rainfall might in some Chalk districts pro- 

 duce saturation nearly to the surface. 



He strongly objected to Prof. Seeley's ideas respecting the deposit 

 on the hill tops : it was more probable that the heights of the South 

 Downs were capped by a chemical deposit, which was the residuum 

 of the chalk already removed by solution. 



He again expressed an opinion that Mr. Reid's theory was well 

 worthy of consideration. 



Dr. Geikie had accompanied the Author over the ground and 

 considered him to be on the right track. Without doubt the valleys 

 were the result of subaerial denudation, and he was astonished at 

 what had fallen from Prof. Seeley. The valleys were doubtless 

 outlined before the Chalk was exposed at the surface, and their sub- 

 sequent erosion in the Chalk had been effected by solution and 

 mechanical abrasion under conditions which have now disappeared. 



Dr. Hicks observed that Mr. Eeid spoke of great cold, therefore 

 the period he was describing must have been the climax of the Ice 

 Age. The animals found in the Pleistocene deposits referred to were 

 simply driven from their northern home by the advance of the ice. 

 Man would follow the animals on which he lived ; therefore the 

 implements obtained from these deposits belonged, probably, to 

 the northern man, who must be considered as of pregiacial age. 



Mr. Toplet, after alluding to the breadth of the discussion, bore 

 testimony to the value of the Author's hypothesis. It was not a 

 new idea that the Coombe Rock represented the glacial deposits of 

 the north of England ; but the really new point in the paper was the 

 notion of the ground south of the area under ordinary glacial condi- 

 tions having been solidly frozen ; and if the whole country were 



