28 Cincinnati Society of Natural History. 
tion supposed by the theory now before us, even if aided.by what Sir 
Charles truly regards as a more important cause of cold—namely, a- 
different distribution of land 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 itin 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 
any 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 carry 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 striz 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 country. 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, 
