258 REPORT OF MEETINGS FOR 1902 



by no means uniform. In some parts of a valley the depression 

 was deepened very much more than in some of the parts 

 adjoining, in which respect glacial erosion diflPers essentially 

 in its work from the eroding work of a river, for in this 

 case the bed of a water course everywhere slopes more or 

 less downhill and seawards. 



About Peebles one of these cases of unequal erosion took 

 place on a somewhat extensive scale. The whole of the valley 

 for several miles above the river gorge on which Neidpath 

 Castle is situated was scooped out by the ice to perhaps as 

 much as a hundred feet lower than it was before ; while at 

 the gorge mentioned it is probable that the erosion was 

 relatively small. In other words, while a great rock basin 

 was being ground out by the ice above Neidpath, that part 

 of the valley where the gorge is now was spared. So a 

 great lake basin was formed, whose rock barrier extended 

 from near the foot of the Manor Water to close upon Peebles 

 itself. All the valleys above this, including the Lyne Water, 

 were locally deepened and widened, more or less, by the same 

 agency. 



So it happened that when the Age of Snow was giving 

 place to what one is almost justified in calling the Age of 

 Rain, and the great masses of ice were melting away, extensive 

 lakes gradually formed within each of the valleys. A large 

 lake extended from far above Drummelzier to a mile or so 

 below Dalwick. Another series of lakes occupied part of 

 the Lyne. And the same may be said of other river courses 

 near Peebles. 



By degrees, however, two other sets of factors came into 

 operation, both tending, as must always be the case, to reduce 

 the lakes to the normal condition and replace them by rivers. 

 One of these, in the present case, was the lowering of the 

 bed of the river in what is now the gorge below Neidpath, 

 which tapped the lakes and eventually drained them. The 

 other was the steady inflow of sediment, by which the remaining 

 water of the lakes was gradually replaced by silt, and alluvial 

 haughs left in their stead. 



Perhaps this explanation will give an answer to the question 

 why there are so many high-level river tejrraces about Lyne 

 Church. 



