412 PREHISTORIC E UROPE. 



Glacial Period of geologists cannot be of such extreme antiquity 

 as is commonly believed. But this objection disappears when 

 we learn that local glaciers occupied those mountain-valleys 

 in Postglacial times, and descended in many cases to the sea- 

 level at a time when Neolithic man was an occupant of the 

 country. Prom certain evidence met with both in the Southern 

 Uplands and Northern Highlands, the advent of these later local 

 glaciers would seem to have been preceded by a period during 

 which the snow-fields and glaciers of the previous Ice Age had 

 either vanished or become greatly attenuated. It is frequently 

 impossible, however, to distinguish between the morainic d4bris 

 of late glacial and the moraines of postglacial times. The 

 glaciers of the latter period appear in some cases to have 

 ploughed out the boulder-clay of the Ice Age proper, so that 

 their moraines often rest directly upon the rocky pavement of 

 the valleys. But this of itself can hardly be taken as a proof of 

 the postglacial age of those glaciers, for, during the retreat of 

 the local glaciers towards the close of the true Glacial Period, 

 the older drifts would be liable to the same kind of erosion. It 

 is rather from the general appearance of freshness presented by 

 the local moraine-mounds of postglacial age that their more 

 recent date can be inferred. Let me give an example or two of 

 the appearances I refer to. In the neighbourhood of Loch Skene 

 in Peeblesshire is a group of finely-preserved moraines, which 

 have been described in detail by Professor Young. 1 They are 

 strictly local and confined to the heads of certain valleys, some 

 of which drain into the Moffat and Yarrow waters, while others 

 are tributary to the river Tweed. So fresh and beautifully pre- 

 served are the mounds and cones that it is difficult to believe 

 that they can date back to a period so vastly remote as the Ice 

 Age is believed to be. Now all the valleys leading down from 

 the heights above Loch Skene are sprinkled with morainic dSbris, 

 gravel, and boulder-clay, which may be followed down into the 

 main valleys and across the low grounds to the sea. These 

 deposits are the dibris accumulated and frequently re-arranged 



1 Quart. Jour. Geol. Soc, 1864, p. 452. 



