MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 455 



This accumulation of sand and gravel, is in all respects so different from the 

 boulder clay, that it must have been deposited under very different circumstances, 

 (1.) The boulder clay is almost uniformly the lowest deposit. (2.) It is never 

 stratified. (3.) It contains much larger fragments of rock than the superincum- 

 bent beds of gravel. 



From these data I infer, that the boulders and clay were transported by tu- 

 multuous waters, whilst the gravels and sands were deposited in waters compa- 

 ratively tranquil, though affected by currents. 



Now, here the question occurs, Whether the sands and gravel, just alluded to, 

 were deposited during the rush of waters which bared the west faces of the hills ? 

 I should be inclined to think, that they had been spread over the country pre- 

 viously to this event ; and that the effect of that violent and universal rush of 

 waters, must have been to sweep away a great proportion of these superficial 

 deposits, leaving undisturbed only those on the east side of hills, and, perhaps, 

 adding to the deposits there. In confirmation of this last remark, reference may 

 be made to the enormous accumulation of gravel, on the east sides of the Cheviot 

 hills (near Palinsburn and Wooler), of the Galashiels hills, and of Lamberton hill 

 in Berwickshire. 



If, then, previous to the rush of waters from the westward, the country had 

 been overspread with sand and gravel, this would indicate that it must, at all 

 events, down to the date of that occurrence, have been under the waters of a sea, 

 which transported sand and gravel from great distances. In no other way is it 

 possible to account for the extensive beds of sand and gravel, often stratified, which 

 occur in many parts of Roxburghshire, and particularly in Liddesdale, in situ- 

 ations far above and beyond the reach of rivers. In some places (as at Max- 

 ton and Plewlands), pebbles of gneiss have been found in cutting drains, which 

 must have been brought at least 80 or 100 miles from the west or north-west. 

 We have seen, that, when the red sandstone rocks were being deposited, the waters 

 of an extensive ocean prevailed to a height of at least 1100 or 1200 feet above its 

 present level. The existence of gravel-beds as well as boulders, at much about 

 the same height, indicates, that, down to a very recent geological period^ there had 

 been no change in the relative levels of sea and land. When the sea did retire to 

 its present level, is quite a separate question ; the solution of which in no way af- 

 fects the soundness of the views above suggested. 



It may, however, be asked, How it is possible, consistently with these views, 

 to explain the origin of the remarkable knolls and ridges described in the first part 

 of this Memoir, and for the production of which it has been thought necessary to 

 invoke the aid of glaciers ? It may be conceived how the waters of an ocean 

 charged with sandy sediments, and rolling along gravel, should form beds more 

 or less horizontal. But how can they form harrow ridges of sand and gravel, 



VOL. XV. PART III. 6 P 



