10 PROFESSOR P. F. KENDALL AND MR E. B. BAILEY 



to the general aspects of the case, he continues : " In all these cases the course of the 

 dry valleys is the same, north-eastwards, and is, therefore, at right angles to the present 

 stream courses. It is difficult to explain their formation by means of the small brooks 

 which flow in their neighbourhood, and their form is not that which would result from 

 glacial erosion. There are many such valleys, some of which are mentioned in the 

 Berwickshire memoir ; the same explanation does not, however, remove the difficulties 

 in each case ; their solution must, therefore, wait the results of more extended 

 inquiry." 



AVhen we add that many of the most typical examples are excavated entirely in 

 drift deposits, it becomes evident that the anomalies referred to cannot be regarded as 

 vestigial inheritances from a pre-glacial drainage system, nor can they be accounted for 

 as the consequence of a selective erosion acting along lines of geological weakness. 

 From what has already been stated the reader will have gathered that we intend to 

 apply the same explanation here as was developed by one of us * in order to account 

 for similar peculiarities in the Cleveland district of Yorkshire. 



Sir Archibald Geikie's remark with reference to the channel on the south side of 

 St Helen's Church might be repeated a score of times. " With the present configura- 

 tion of the land no stream could ever have flowed along this ravine." In the particular 

 case he cites, it might perhaps be suggested that the valley has been cut back to by 

 recent marine erosion, but such an explanation carries no weight in view of the 

 numerous inland examples. The inadequacy of " the present configuration of the 

 land " is nowhere better illustrated than in certain cases where stream gorges have been 

 cut into the uniform slope of a hill side, following instead of crossing the contour lines. 

 The Pressmennan Loch channel furnishes an imposing example. During the initiation 

 of this gorge it is necessary to suppose that the ice front itself supplied the northern 

 containing wall of. the stream, until the latter had sunk its channel into the solid rock. 



Almost equally impressive is the entrance to the Chesters Quarry ravine, a mile north 

 of Garvald. It seems at first sight indeed to have been fashioned in sheer contravention 

 to the ordinary laws of Nature, for it originates on an open plane, and straightway leads 

 across the imposing spur of Whitelaw Hill. But once in imagination replace the ice 

 sheet to the north and the difficulty vanishes. A lake forms behind the rocky ridge, 

 and its escaping waters are forced to take the route which at the present time seems so 

 unnatural. 



These are merely examples chosen well-nigh at random from a host. The Chesters 

 Quarry defile may also be noticed here as a representative " dry valley " ; for not only 

 was it cut entirely by glacially diverted waters, but being so cut it has in later times 

 failed to retain any stream of its own. Naturally, however, a great number of glacial 

 drainage channels are still employed as watercourses ; there is in such cases a very 

 marked tendency leading to the formation of corroms and the consequent establish- 

 ment of short cuts, so that the inadequacy of "the present configuration of the land" 



* P. F. Kendall, "Glacier-lakes in the Cleveland Hills," Q.J.G.S., 1902. 



