GLACIAL AND INTERGLACIAL BEDS 3°7 



Metropolitan power house, a mile or two north of Toronto, 

 Amnicola limosa, a Succinea and fragments of another species. 

 These occur at 220 feet above the lake, but the sand containing 

 them runs up to 247 feet and may correspond to the silty sand 

 between till No. 2 and till No. 3 at Scarboro'. 



One of the recessions of the ice, perhaps the one just men- 

 tioned, appears to have been very extensive, for two thick beds 

 of bowlder clay are found to be separated by stratified materials 

 at numerous points on the lake shore as far east as Newtonville, 

 fifty miles from Toronto. The same relationship is found near 

 the headwaters of the Don, about eight miles north of the city, 

 and also in ravines to the east, but has not been observed to the 

 immediate west ; though the stratified clays lying between two 

 layers of till at Dundas and at several points near Niagara Falls 

 may correspond to the same interglacial stage. In that case the 

 ice must have withdrawn eighty miles in a northeasterly direc- 

 tion before advancing again. 



During the first recession of the ice the lake was dammed to 

 a level at least 160 feet above the present, for roughly stratified 

 grayish clay with a few small polished and striated stones is 

 found at many points at about this level, filling in hollows of the 

 bowlder clay, as at the Dutch church and Taylor's brickyard. 

 Afterwards, as shown above, the water stood much higher, since 

 stratified materials are found 360 feet above Ontario or 606 feet 

 above the sea, and may have formed part of a large body of 

 water, covering Lake Erie as well as the western end of Ontario. 

 As the whole of these stratified clays and sands were afterwards 

 overridden by the ice and covered with the latest sheet of till 

 they must be looked on as interglacial. The highest bowlder 

 clay has not yet been traced with certainty west or south of the 

 Toronto region, however, since the four sheets of bowlder clay 

 are very much alike and cannot be discriminated when found 

 alone; and there is a possibility that it ends here, and that the 

 water then filling the Ontario basin was continuous with that of 

 some of the successors of Lake Warren. If so, beach lines may 

 have been formed to the west or south of Lake Ontario while 



