OF CENTRAL CANADA PART V. 



313 



bounded by the crystalline, Archsean regions already described. Its 

 1 western boundary is the high escarpment which 



runs from the Niagara river, near Queenston, in a 

 general westerly direction beyond Grimsby, to the 

 back of Hamilton, then northwards by Dundas, 

 Georgetown, Bellefontaine and Orangeville, to the 

 northern part of Nottawasaga, and from thence 

 north-westerly by the " Blue Mountains," etc., to 

 Cabot's Head on Georgian Bay. From the latter 

 point, eastward, the district includes the shore of 

 the Bay to a short distance beyond the mouth of 

 the River Severn, where the crystalline rocks of 

 the Archaean region come up from beneath its 

 strata. The Lake Ontario District thus includes 

 portions of the Counties of Frontenac, Addington, 

 Hastings, Peterborough, Victoria, Simcoe, Peel, 

 Halton, Wentworth and Lincoln, with the whole 

 of York, Ontario, Durham, Northumberland and 

 Lennox. Numerous lakes, of which Lake Simcoe 

 is the largest, lie within its area, or form a more 

 or less continuous band along its northern edge 

 where the Archsean country commences. The 

 River Trent, which rises in the latter, and flows 

 through a series of small lakes into the Bay of 

 Quint^ and Lake Ontario, is its most important 

 river. Among other streams flowing southwards 

 are the Salmon or Shannon, the Moira, the Don, 

 Humber, and Credit. Northward-flowing rivers 

 include the Scugog, which flows from the small 

 lake of that name, 800 feet above the sea-level, into 

 Sturgeon Lake ; the Holland river which flows 

 into Lake Simcoe, the northern waters of this 

 lake communicating by the Severn with Georgian 

 Bay ; and the Nottawasaga, on the extreme west of 

 the district, flowing into Nottawasaga Bay, a broad 

 inlet of the Georgian Bay waters. In its surface features the district 

 is generally of an undulating character, with but few abrupt inequal- 

 ities of level. The ground rises gradually from Lake Ontario (232 





V\\ 



