66 



as rendering it improbable. The other condition was maintained 

 as probable, on the ground that the changes which have undoubted- 

 ly taken place in the positions of the rocky masses forming the crust 

 of the earth, prove that parts of these masses had been depressed, 

 while others had been elevated ; so that the probability was, that 

 the Cuchullin Hills had stood at a higher elevation than they do at 

 present, reaching above the line of perpetual congelation. 



The crust of the earth having been broken up, was formerly pro- 

 pounded by the author of this paper as having been the cause of 

 such a disturbance of land and water, as would fully account for all 

 the phenomena now presented by the surface of the globe. It was 

 stated, that, while no proof could be brought to shew a change of 

 climate, we had evidence in abundance of intense internal heat, 

 which has been known to have produced force sufficient to elevate 

 the land. Nothing seems more likely, when the bursting of the 

 crust gave vent to the expansive matter, than the sinking of much 

 of the crust into the vacuities produced by its escape, and the tilt- 

 ing up of the rest ; thus giving to the surface its present rugged 

 and uneven aspect. During such a convulsion, masses bearing 

 glaciers may have sunk with them below the line of perpetual con- 

 gelation . 



The observations on Mr M'Laren's theory, which ascribed two 

 different co-existing phenomena (striated marks and travelled boul- 

 ders) to two causes — the one glaciers, and the other icebergs — went 

 to shew, that, if a glacier had existed in the Gareloch, it would be 

 necessary to determine whether the boulders were deposited, and 

 the glacier was formed before or after the rising of the sea, and 

 after its subsidence ; the sea having been supposed to have risen 

 2000 feet, to admit of icebergs bearing boulders floating into the 

 Gareloch. This elevation of the level of the sea had not been ac- 

 counted for in any way ; nor had it been considered that the sup- 

 position involved its having risen all over the globe ; and no space 

 had been provided to receive it when it retired. It was shewn that, 

 in such a condition of things, Scotland must have been a cluster of 

 small islands, the summit of the present mountains, which certainly 

 would have had a climate colder than the country generally has 

 now. But it was also shewn, that were the sea elevated, as sup- 

 posed, 2000 feet higher than at present, the regions where icebergs 

 exist now would have been a solid mass of immoveable ice, extend- 

 ing far above and'^eyond the land from which icebergs, in our day, 

 are occasionally detached. It was supposed that the phenomena 



