LABRADOR GLACIER LATER THAN KEEWATIN 213 



Ohio, and, according to Prof. E. H. Williams, at Warren, in western 

 Pennsylvania, while red jasper conglomerate bonlders from north of 

 Lake Huron occur as ,f ar east as Ashtabula County, in the extreme north- 

 eastern part of Ohio. It is hardly possible that these materials could 

 have been transported so far east during the later portions of the glacial 

 invasions, for that invasion consisted of Labradorian ice. The so-called 

 Illinoisan deposits pushed from the eastward across the State of Illinois, 

 and even extended a short distance into eastern Iowa, where in the 

 vicinity of Keokuk red jasper conglomerate boulders from the north of 

 Lake Huron are found in considerable abundance. It is thus certain that 

 the glacial movement from the Labrador center was later than that from 

 the Keewatin center. For a long distance east of the Mississippi Eiver 

 we know that the deposits of the Labrador ice-sheet overlie those of the 

 Keewatin sheet. It is noticeable also, as already indicated, that the ice 

 departed from the western regions long before it disappeared from New 

 York, New England, and Quebec. The distinct signs of inter-Olacial 

 epochs are only in this western field. No satisfactory evidence of ex- 

 tended inter-Grlacial epochs has been found in the eastern regions. As 

 bearing on the larger question of an inter-Glacial epoch covering the 

 whole northern hemisphere, it is also significant that the geologists of 

 Great Britain now maintain that' they discover no evidence of such an 

 inter-Glacial epoch in the British Isles, nor do the geologists of Sweden 

 in Scandinavia.^^ 



I long ago called attention to the fact brought out during the survey 

 of the terminal moraine in Pennsylvania by Professor Lewis and myself 

 that the boundary of the glaciated areas in the central and the eastern 

 part of the United States consists of the arcs of two circles, with their 

 centers respectively in Labrador and the Lake Superior region. The 

 junction of these arcs is at Salamanca, New York, almost exactly on the 

 meridian of Toronto. It is, therefore, a plausible hypothesis that the 

 deposits of Toronto, where these contending ice-fields met, should reveal 

 many abnormal phenomena. 



Summary 



The following order of events would seem to explain all the facts : 

 1. First, the Keewatin Glacier pushed southward to the glacial limit 

 in the Mississippi Valley and eastward as far as western Pennsylvania 



1° See Lamplugh's "Presidential address to the geological section of the British Asso- 

 ciation for the Advancement of Science," at York, 1906 ; also paper before the Interna- 

 tional Geological Congress, at Toronto, 1913 ; also Nils Olof Hoist's "Forhistorisk gruf- 

 bryting i Sverige," in which he estimates the close of the Glacial period in Sweden as 

 not more than 7,000 years ago. 



