ON THE GLACIATION OF EAST LOTHIAN SOUTH OF THE GARLETON HILLS. 7 



The third example occurs at Woodcotte Park, a mile to the east of Fala. The 

 limestone forms two little knolls known as the Little Hill and Meikle Hill respectively. 

 Here, as at Kidlaw, the field evidence strongly suggests that the limestone is resting 

 on the Upper Old Red Sandstone, only in this case upon the south side of the 

 Lammermuir fault. The exposure was known some sixty years ago to Charles 

 Maclaren * and David Milne HuME,t who regarded it as belonging to a natural outcrop. 

 Maclaren remarks, however, that he saw none in place. The evidence for believing 

 that these knolls consist of transported limestone is therefore identical with that put 

 forward in respect to the Kidlaw example, and the probability of the interpretation is 

 heightened in that it is not invoked merely to explain a single occurrence. It is 

 noteworthy that Mr Howell in his mapping long ago did not treat these smaller 

 masses as being in place, although one of them was formerly quarried and burnt 

 for lime. 



The carboniferous limestone seems in certain other places to figure more largely in 

 the drift than might at first be expected ; this suggests that in pre-glacial times the 

 more important beds of limestone may have given rise to conspicuous little escarpments 

 with long, exposed dip slopes, and that these furnished an abundant supply of blocks 

 during their degradation by the ice sheet, while at the same time they may have 

 afforded favourable opportunity for the transport of big masses. 



The Retreat of the Ice Sheet. 



We have now examined some of the results of the action of the ice sheet during its 

 maximum development, but perhaps even more interesting still are the circumstances 

 of its retreat. When gradually it was forced to give place to other agents of erosion, 

 it yet was able for a while to impose special conditions upon their operation. Thus 

 step by step the enveloping ice shrank back to leave the Lammermuirs standing like a 

 stone in the midst of melting snows ; and stage by stage the memorials of this retreat 

 were furnished by the obstructed drainage of the hill country, joined by the waters 

 issuing from the glacier itself : There are whole suites of channels to bear witness to 

 the former presence of swollen torrents, linking together the long chains of lakes, which 

 then rested in temporary support between the steep ice margin and the slopes of the 

 hill country to the south ; and there are also the deposits which accumulated in these 

 lakes and at many an intervening point where the connecting streams had not as yet 

 cut gorges for themselves. 



One can even recognise by a careful investigation of the evidence that there were 

 times when the ice sheet renewed its vigour. One can trace its oscillatory re-advances : 

 here it spreads its boulder clay over the floor of a lake where previously sand and silt 



* Sketch of the Geology of Hfe and the Lothians, 1839, p. 74. 

 t Coalfields of the Lothians, lb39, p. 103. 



