216 Tertiary. 



tion supposed by the theoiy uow before us, even if aided by what Sir 

 Charles truly regards as a more important cause of cold — namely, a 

 different distribution of laad and water, in such a manner as to give 

 a great excess of land in high latitudes. 



2. It seems physically impossible that a sheet of ice, such as that 

 supposed, could move over an uneven surface, striating it in directions 

 uniform over vast areas, and often different from the present inclina- 

 tions of the surface. Glacier ice may move on very slight slopes, but 

 it must follow these ; and the only result of the immense accumulation 

 of ice supposed, would be to prevent motion altogether by the want of 

 slope or the counter-action of opposing slopes, or to induce a slight 

 and irregular motion toward the margins, or outward from the more 

 prominent protuberances. 



It is to be observed, also, that, as Hopkins has shown, it is only the 

 sliding motion of glaciers that can polish or erode surfaces, and that 

 an^^ internal changes, resulting from the mere weight of a thick mass 

 of ice resting on a level surface, could have little or no influence in 

 this way. 



3. The transport of bowlders to great distances, and the lodgment 

 of them on hill-tops, could not have been occasioned by glaciers. 

 These carr}^ downward the blocks that fall on them from wasting cliffs. 

 But the universal glacier supposed could have no such cliffs from 

 which to collect ; and it must have carried bowlders for hundreds of 

 miles, and left them on points as high as those they were taken from. 

 On the Montreal Mountain, at a height of 600 feet above the sea, are 

 huge bowlders of feldspar from the Laurentide Hills, which must have 

 been carried -50 to 100 miles from points of scarcely greater elevation, 

 and over a valley in which the strife are in a direction nearly at right 

 angles with that of the probable driftage of the bowlders. Quite as 

 striking examples occur in many parts of the countrj'. It is also to 

 be observed that bowlders, often of large size, occur scattered through 

 the marine stratified clays and sands containing sea-shells ; and what- 

 ever views may be entertained as to other bowlders, it can not be 

 denied that these have been borne by floating ice. Nor is it true, as 

 has been often affirmed, that the bowlder clay is destitute of marine 

 fossils. At Isle Verte, Riviere du Loup, Murray Bay, and St. 

 Nicholas on the St. Lawrence, and also at Cape Elizabeth, near Port- 

 land, there are tough stony clays of the nature of true " till,'' and in 

 the lower part of the drift, which contain numerous marine shells of 

 the usual Post-pliocene species. ■ 



