40 Latest Geological Changes in the South of Scotland. 



litary exception ; for wherever we have observed those mounds, 

 they are always situated according to the natural declivity of 

 the ground in the vicinity of elevated ranges, without regard 

 to any direction. We could direct attention to many more of 

 a similar character, but as we have drawn out this paper to 

 a greater length than was anticipated, we hasten to conclude 

 as briefly as possible with a recapitulation of the principal 

 points. 



When the summits of our hills were emerging out of the 

 ocean, strong currents (perhaps periodically), accompanied 

 with numerous floating icebergs, seem to have been furiously 

 driven along, denuding their summits and sweeping the debris 

 to the east, forming the beds of boulder clay commonly de- 

 nominated til ; still as the land was upheaving and the higher 

 peaks rising above the denuding action, the onward wave and 

 ice, ever lashing against their western faces, rendering them 

 bare and precipitous, and sweeping round their sides, cutting 

 out the rocky terraces, grinding down and rounding over those 

 saddle-backed ridges as they were raised to near the surface, 

 while occasionally from some overhanging precipice masses of 

 the rock would fall upon the ice, and be borne along with it until 

 its floating raft gave way, or until it was dashed from its seat 

 and dropt upon the bottom. Anon, while the land by inter- 

 nal throws was rising step by step, a part of the older ruins 

 would be removed to a greater distance, and be again lodged 

 over its lower flanks, and while the lighter debris was being 

 swept away, the larger blocks would be further rolled along 

 and finally left upon the surface. And lastly, by shallower 

 currents, part of the debris, where it was exposed to their ac- 

 tion, would be further removed, and thrown up in beds of 

 sand and gravel into sheltered situations. In the course of time, 

 when the valleys had become elevated above the ocean, the 

 accumulating snow upon the hills would commence descend- 

 ing down the declivities in the glacier form, to those land 

 straits where the moraines are still to be seen, bearing along 

 with them a part of the debris which they had collected in 

 their course, and finally retreating after their beneficent task 

 was accomplished, leaving those imperishable records to attest 

 that they had once been there. . 



We understand that the glacier theory is rejected by some, 

 who reason in this manner : — Animal and vegetable life, during 

 the rem of the carboniferous system, was such even in our 

 northern latitude as could only have existed in a climate such 

 as the tropics, and although a progressive change had been 

 going on until the aera of the newer tertiary, still even then it 

 had been much above the present. We hold that argument 



