Notices of Memoirs — Olacial Deposits at Toronto. 515 



No evidence was discovered of any great elevation of this central 

 area iu Glacial or immediately Pre-Glacial times, and, in the 

 absence of such evidence, it would seem not improbable that the land 

 then stood at about the same height above, the sea as it stands at 

 present. In this case, the moisture giving rise to the immense 

 precipitation of snow would have been derived from the adjacent 

 wafers of Hudson Bay and the Arctic Ocean. 



The name Keewatin glacier has been applied to this central con- 

 tinental ice-sheet. In general character it appears to have been 

 somewhat similar to the great glacier of North- Western Europe, 

 with a centre lying near the sea-coast, a steep and short slope 

 seaward, and a very much longer and more' gentle slope towards the 

 interior of the continent. But there was this difference between the 

 two, that the centre of the latter was over a high rocky country, 

 from which the ice naturally flowed outwards towards the surrounding 

 lower country ; while the centre of the former was over what is now, 

 and was probably also then, a low-lying plain, on which the snow 

 accumulated to such depths as to cause it to flow over country very 

 considerably higher. 



After the Keewatin glacier had reached its full extent, it began 

 gradually to decrease in size. As it disappeared from the Northern 

 States and the North- West Territories of Canada, it left a series of 

 moraines, many of which can be readily traced across the unwooded 

 country as ridges of rounded stony hills. While retiring down 

 gradually'' descending slopes, many temporary extra-glacial lakes 

 were formed in front of it, and were drained one after another as it 

 retired to still lower country. Before it had withdrawn from the, 

 Winnipeg basin, it was joined by an advancing glacier from the east, 

 and, in front of the two, Lake Agassiz, one of the largest of the 

 extra-glacial lakes, was formed. 



In its final stages the general gathering-ground of the Keewatin 

 glacier seems to have moved still farther eastward, or nearer to the 

 coast of Hudson Bay, and to have broken into several separate 

 centres, one of which lay over the country south-east of Yath-kyed 

 Lake, while another was probably located north of the head of 

 Chesterfield Inlet. 



After the retirement of the Keewatin glacier the land in the 

 vicinity of Hudson Bay stood from 500 to 600 feet below its present 

 level, and gradually rose to its present height. 



HI. — Glacial and Interglaoial Deposits at Toronto. By 

 Professor A. P. Coleman, Ph.D., Toronto University. 



THE ravines of the river Don at Toronto and the lake cliff's of 

 Scarborough Heights, a few miles to the east, provide exceed- 

 ingly interesting sections of the drift, from 100 to 350 feet in 

 thickness, displaying three or more sheets of till- and a varying 

 number of interglaoial beds. 



The most important section, at Taylor's brickyard in the Don 

 Valley, shows a lowest till overlying Cambro-Silurian shale of 

 Hudson River age. Upon this rest 18 feet of sand and clay, con- 

 taining many unios and other shells, as well as leaves and pieces 



