574 REPOKT OF NATIONAL MUSEUM, 1904. 



condition of the sea, as shown by the fossils of that period. He agreed 

 with Lyell in regarding the theory of the varying eccentricity of the 

 earth as expounded by Croll as insufficient; moreover, it seemed to him 

 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 inclination of the 

 surface. 



He was further influenced in his opinion by the work of Hopkins, 

 who showed, apparently, that only the sliding motion of glaciers 

 could polish or erode rock surfaces, and the internal changes in their 

 mass — the result of weight — could have little or no effect. Glaciers, 

 moreover, he argued could not have transported the bowlders great 

 distances and lodged them upon the hilltops, and the universal glacier 

 would, moreover, have no gathering ground for its materials. The 

 huge feldspar bowlders from the Laurentide Hills, stranded at Mon- 

 treal Mountain at a height of 600 feet above the sea and from 50 to GO 

 miles farther southwest, and which must have come from little, if 

 any, greater elevation and from a direction nearly at right angles to 

 that of the glacial striae, were against the ice-sheet theory, as were 

 also the large bowlders scattered through the marine .stratified clays 

 and sands, and the occurrence of marine fossils in the lower part of 

 the drift, in the true till near Portland and Cape Elizabeth, Maine, and 

 at various points on the St. Lawrence in Canada. In the Post- 

 Pliocene deposits of Canada he found evidence of a gradual elevation 

 from a state of depression which may have amounted to more than 

 500 feet, while only the bowlder clay represents the previous subdi- 

 vision, and only striations on the rocks indicate an ice-clad condition 

 of the land. Both plant and animal life indicated to him that the con- 

 ditions of temperature of the sea were not greatly different from those 

 of to-day. 



Referring to the direction of the stria?, he found evidence such as 

 led him to declare without hesitation that their direction is ''from the 

 ocean toward the interior against the slope of the St. Lawrence Val- 

 ley. " This, he felt, at once disposed of the glacial theory for the 

 prevailing set of striae, since he could not suppose a glacier to move 

 from the Atlantic up into the interior. On the other hand, he 

 regarded it as eminently favorable to the idea of ocean drift. A 

 subsidence sufficient to convert the Canadian plains, New York, and 

 New England into a sea would, he thought, cause the Arctic current 

 to pour over the Laurentide rocks on the north side of Lake Superior 

 and Lake Huron, cutting out the softer strata to form their beds, and 

 drifting their materials to the southwest. The lower strata of the 

 current would be diverted through the strait between the Adirondacks 

 and Laurentide Hills, and, flowing over the ridge of hard rocks which 

 connects them at the Thousand Islands, would cut out the lony - basins 



