NATURAL HISTORY, TORONTO REGION 



The geological history of the region in Post- 

 glacial times begins with the removal of the remnants 

 of ice which blocked the St. Lawrence outlet, when 

 the water sank from the Iroquois stage to sea level 

 for a time, though the great inflow of fresh water 

 prevented the basin from becoming salt. Meantime, 

 the region to the northeast was slowly rising and at 

 length cut off the basin of Ontario from the Gulf of 

 St. Lawrence, when Lake Ontario came into being. 

 It probably fell far short of its present westward 

 extension at first, but the differential elevation of 

 its outlet at the Thousand Islands has backed up the 

 water, which now stands 246 feet above the sea. 



THE SOILS OF THE TORONTO REGION. 



There are many varieties of soil in the district 

 surrounding Toronto, resulting from the events of 

 Pleistocene times just detailed. Residual soils due 

 to the decay of ancient rocks in place scarcely exist 

 in the region, which is almost wholly covered with 

 glacial drift or with old lake deposits. The glacial 

 materials include certain moraines to the north so 

 thickly strewn with stones as to be almost valueless 

 to the farmer, a few kames of barren gravel, and 

 some wide stretches of hopeless outwash sand, all 

 practically useless when stripped of their forest 

 growth; but they also supply the strong clay soils 

 of the broad rolling surface of till covering much of 

 the province, sometimes rather stony, but rich in 

 lime, potash and phosphorus derived from the ground- 



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