﻿344 SOLUTION -VALLEYS IX THE GLYME AEEA. [Ang. 1908, 



by the previous speaker, and was of opinion that that, too, had been 

 formed largely by chemical action in a similar manner to many of the 

 Derbyshire dales. He felt, however, that the action was a combined 

 one, namely, chemico-mechanical. Although he was unfamiliar 

 with the Glyme area, the slides exhibited appeared to him to show 

 none of the characteristic features of the chemico-mechanical 

 valleys of the Chalk or the Carboniferous Limestone, If the 

 Author's views were correct, then the valleys to which he had 

 referred had been considerably modified by subaerial erosion. 



Mr. G. Bakeow, while admiring the Author's enthusiasm, thought 

 that he was inclined to push the solution-theory of the origin of 

 the valleys under discussion a little too far. At no great distance 

 to the north-east, the Great Western Eailway cuttings showed that 

 nearly all the lime had been dissolved out of most of the calcareous 

 sandstone, which formed the bulk of the lowest portion of the Lower 

 Oolite. This dissolution had taken place evenly, without any refer- 

 ence to special lines of drainage, such as small valleys or hollows. 

 Once a valley had been formed, in rocks capable of solution, the com- 

 position of the latter did undoubtedly facilitate the widening and 

 deepening of the valley by solution. 



Prof. Garwood expressed his great interest in the subject dealt 

 with by the Author. He asked whether the even-graded valleys, 

 shown in the photographs, were tji'pical of these ' solution '-valleys. 

 He would have expected to find surface-depressions occupied, at all 

 events in fiood-time, by water due to unequal depression of the 

 surface. In districts where he had studied the eS'ects of solution 

 in the Alps, this was always a characteristic feature. 



The President thought that the Author had entered upon a very 

 promising field of investigation, and agreed with him in attributing 

 a very important role to subterranean solution, an agency which 

 seemed to have played a great part in the formation of the dry 

 valleys of the Chilterns. The absence of any features resembling 

 dolina was certainly a difficulty, but in an advanced stage of 

 erosion these might disappear or pass into hollows resembling 

 cirques. 



The Author briefly replied, saying that the characteristic lime- 

 stone valley-contours immediately ceased, and were replaced by 

 a level floor cut by a narrow stream-gorge, when the Lias was 

 reached in descending the Charlbury and other valleys ; but such 

 confirmatory marks of erosion were never observed in any limestone- 

 valley. He hoped to deal with the region much more fully and 

 in greater detail at a later period, as suggested by the President. 

 The evidence presented in the field left, however, no conclusion 

 possible but that lowering action in the dry valleys was entirely 

 underground and due to solution. 



