NATURAL HISTORY, TORONTO REGION 



glacial episodes was long, and that it included great 

 cnanges of climate and of physical conditions is 

 proved by the extent and character of the deposits 

 'and 'by their fossils. This set of interglacial beds, 

 which has been called the Toronto Formation, 

 includes a thickness of 185 feet of sand and clay 

 deposited as a delta by . a great river flowing from 

 tne north into an interglacial Lake Ontario. 



Three outcrops are of special interest, one at the 

 Don Valley brickyard, another at Scarborough 

 Heights, and a third near Christie and Shaw Streets. 

 At the brickyard, which is just east of Rosedale, the 

 lowest boulder clay is seen resting upon the Lorraine 

 shale, followed by 25 feet of stratified clay and sand 

 containing many shells and leaves of trees as well as 

 logs of wood. Above this there are 21 feet of strati- 

 fied clay with a little peaty matter, but no other 

 organic remains. This is followed by a second 

 sheet of boulder clay and then by 80 feet of stratified 

 clay from which no fossils of any kind are known. 

 Boulders on the Iroquois terrace above imply a third 

 boulder clay removed by wave action. 



The fossils from the Don valley interglacial sec- 

 tion include a dozen species of the Unionidae, four of 

 which now live in Lake Ontario, three others in 

 Lake Erie, while the other five do not occur in 

 Canada but are found in the Mississippi waters. 

 There are in addition twenty-nine species of smaller 

 shells. 



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