172 



A. P. COLEMAN LAKE IROQUOIS AT TORONTO 



ably 50 or 60 feet, above the present lake, but not more, since at this level 

 in the Don beds the warm climate fossils cease, and just below it a series 

 of sand and gravel beds containing much brown oxide of iron hint at shal- 

 low water and oxidation. It may be added that the finding of unios in 

 the position where they lived, just over the boulder clay, 35 feet above 

 lake Ontario, suggests the same thing, as they are stated to live in shallow 

 water only. 



This lake, 50 or 60 feet deeper than the present Ontario, could not have 

 been dammed by ice during the genial Don climate, but may have been 

 held up by a drift deposit near its eastern end, though more probably 

 supported by a more extensive differential uplift near the Thousand 

 islands than the one which holds up lake Ontario at present. 



Without any apparent discordance the warm climate beds are followed 

 by a great thickness of buff stratified clay containing many thin peaty 



strati ned CLay 





Figure 4. — Section at Scarbm'o Hights. 



Ia3^ers with extinct insects and plant remains of a comparatively cool but 

 not arctic climate, as shown by Dr Scudder, Professor Penhallow, Dr 

 Macoun, and others.* The latter may be called the Scarboro beds of the 

 Toronto formation, since best shown at Scarboro hights. At this* time, 

 and probably during the preceding Don stage, a great river, the successor 

 of Spencer's preglacial Lauren tian river, drained the upper lakes, flowing 

 from the Georgian bay to a point north of Toronto, where it formed an 

 extensive delta deposit, now best displayed at Scarboro hights. The 

 Scarboro peaty claj^s rise on the shore of lake Ontario, 95 feet above the 



* See papers previously quoted. 



