166 



A. P. COLEMAN LAKE IROQUOIS AT TORONTO 



hights on the east. Evidently the most effective wave action was pi'ev- 

 alently toward the west in Iroquois times as now. The eastern bar, at 

 the mouth of the Don bay, has a striking resemblance to the present 

 Toronto island, including hollows which once were lagoons. The growth 

 of these bars was followed or accompanied by the almost complete silt- 

 ing up of the two bays, which are now plains more or less dissected by 

 the modern rivers, with their tributaries. 



The shores of lake Iroquois near Toronto were usually low, with 

 gently sloping swells of boulder-clay rising inland, but at two points, 

 the Davenport ridge and Scarboro hights, they formed cliffs, in the latter 



BLACH 



Near 



TORONTO 



Scale of Miles 



FiGUKE 1. — Map of Iroquois Beach near Toronto. 



case rising more than 150 feet above the water. At the highest part the 

 Iroquois shore for half a mile lay to the south of the shore of Ontario, 

 the only instance in its whole circumference where the old shore en- 

 croached on the territory of the present lake. 



Asa result of the growth of the two bars shown on the map, the two 

 main rivers were crowded toward the west, so that when the water fell 

 to its present level the preglacial channels were not again occui)ied, but 

 fresh ones were cut on the westward sides of the valleys. In the case of 

 the Humber we find a wide valle}^ with little rock cutting above the old 

 bar, and a narrow, steep walled channel cut through 50 feet or more of 

 Hudson shale where the river passes the western end of the bar. 



Fossils occur in the gravels of each of the bars described, the one at 

 Toronto Junction afibrding numerous shed horns of caribou and wapiti 



