EXCURSION B 5 



MORAINES NORTH OF TORONTO 



BY 



Frank B. Taylor. 



The moraines to be visited on this excursion were made 

 at a relatively late stage in the retreat of the last or Wis- 

 consin ice sheet, and are the first moraines formed north 

 of lake Ontario. One was made along the southern edge of 

 the Trent valley-lake Simcoe ice lobe. At the locality visited 

 the ice which made this moraine, was moving towards 

 the south and the moraine faces in that direction. The 

 main movement in that lobe, however, was towards the 

 southwest, shown by the axes of many drumlins and drum- 

 loids and by striae and the direction of boulder transporta- 

 tion in the Trent valley and lake Simcoe regions. The 

 direction in this area was about the same during the maxi- 

 mum extent of the ice and during the whole time of its 

 retreat. The other moraine to be visited lies close south 

 of the first and was formed along the northern edge of the 

 ice lobe which lay in the basin of lake Ontario. 



At the greatest extent of the ice sheet, its front reached 

 nearly to Cincinnati, Ohio, about 400 miles southwest from 

 Toronto. The ice which reached this point was part of the 

 great ice stream which moved southwestward through the 

 basins of lakes Ontario and Erie. At the same time the 

 ice front in a direction south-southeast from Toronto 

 reached only to Salamanca, New York, about 120 miles 

 from Toronto. This was on account of the Alleghany 

 plateau, the high mass of which obstructed the southward 

 movement in western New York and Pennsylvania and in 

 northeastern Ohio, and turned the current towards the 

 Southwest along the axis of the lake basins. The central 

 axis of the great ice stream passes about 30 miles south of 

 Toronto, and there was not much change in its position dur- 



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