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The geological character of this plateau, which forms by far the greater part 

 of the Province of Ontario, affords so complete an explanation of the very charac- 

 teristic inland waters of the Province, that some reference thereto will assist the 

 reader in forming a conception of their arrangement. 



A line drawn from the outlet of Lake Ontario, (near Kingston) to Matche- 

 dash Bay in the Georgian Bay, (near Midland in the accompanying map), divides 

 Ontario into two very unequal parts. The northern part is almost entirely 

 formed of rocks of the Laurentian and Huronian series, consisting largely of 

 gneiss and crystalline limestones, which, although apparently altered in their 

 structure, present evidence of being the most ancient sedimentary rocks, and 

 have on this account been termed Archaean. They offer, however, a very different 

 degree of resistance to the eroding and transporting powers of water than do the 

 more recent sedimentary rocks which have not undergone metamorphosis, and 

 thus, instead of continuous river channels, we have series of irregular depressions 

 and clefts converted into lakes by the accumulation of rain and melted snow, and 

 connected with each other by sbort rapid rivers and falls. This country is 

 generally densely wooded, and in many places, owing to the protrusion of the 

 crystalline rocks through the surface clays, unfitted for agriculture, but neverthe- 

 less there are large areas, especially north of the height of land, where the rocks 

 are not exposed and which consequently furnish large tracts of arable land. 

 Only two regions north of the line referred to are underlaid by rocks of more 

 recent origin than the Huronian and Laurentian series. These are firstly, the 

 triangular tongue between the Ottawa and St. Lawrence Rivers as far west as a 

 line drawn from BrockviFe to Arnprior, which is underlaid by Cambrian and 

 Lower Silurian strata ; and secondly, the northern Palaeozoic area of James' Bay, 

 a low, level and swampy region, free from rocks and lakes, extending from the 

 south-west shore of the bay towards the height of land, and involving a consider- 

 able part of the area traversed by the Albany and Moose Rivers. This region, 

 whose steadily flowing rivers, uninterrupted by lakes, present a difference between 

 high and low water mark of about ten feet, necessarily offers somewhat different 

 conditions of life to the finny tribe than the Laurentian region. It is surrounded 

 by a curved rim of Archaean rocks, the unyielding nature of which brings it about 

 that the rivers flowing towards James' Bay meet with a great and rapid descent 

 at the point where they pour over it. The Long Portage of the Abittibe River, 

 marked in the accompanying map, indicates the position of this rim at the point 

 in question. It is similary situated in the Moose and Albany Rivers, but the 

 sides of the rim converge northward to the shores of James' Bay. 



The second and very much smaller part of Ontario is that south of the line 

 described above. It is underlaid by Silurian and Devonian strata in ascending 

 geological order from north to south and west, and is crossed by the great Niagara 

 escarpment, an abrupt rise which extends from the Niagara River by Hamifton, 

 Georgetown, etc., to Cabot's Head in the Georgian Bay. Both east and west of 

 this rise, the country, which forms a continuous tract of fertile farming land, 

 presents a very different aspect from the rugged landscape of the northern 

 Archaean region. On the east the surface is more und dating, the ground gradually 

 rising from Lake Ontario in a series of ridges composed of drift materials to a 

 height of some 700 feet. Some lakes, like Rice Lake and Lake Scugog, are 

 situated in the midst of these drift ridges, others are situated along the line of 

 junction with the Archaean region to the north. To the west of the escarpment 

 on the other hand, the land slopes away gently towards Lake Huron and LaVe 

 Ji-rie, and although, as we shall see, important rivers find their way into both 

 these lakes, yet it differs from the country to the east in the absence of small 

 inland lakes. 



