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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