NATURAL REGIONS OF NORTH AMERICA. CANADA.—As the greater part of Canada east of the Cordillera drains into the Gulf of St. Lawrence, Hudson Bay, and the Arctic Ocean, while the corresponding part of the United States drains into the Atlantic and the Gulf of Mexico, there is some justification for seeking a division of North America into natural regions which do not violate international boundaries.
The Laurentian Plateau is clearly marked off from the remainder of Canada. The Archman rocks of which it is composed, the character of its topography, the poor and scanty soil which covers it, and its climate which is typically that of the high latitudes of the eastern part of a great land mass, all separate it from surrounding regions. Over so great an area temperature and rainfall naturally vary, and it embraces part of two vegetation zones, but the dominat ing geological, topographical, and climatic facts constitute it one natural region which may be subdivided.
The Maritime Provinces form a natural region for somewhat different reasons. They do not belong to the Laurentian region, and are separated by the Appalachian uplift from the more recently formed lands of the continent. Their geological structure is varied, but is largely carboniferous, the soil is good in places, and the climate is less extreme than on the Laurentian Plateau, or even in the St. Lawrence valley. Their position gives them a certain unity, and makes them Canadian rather than American ; their ports are Canadian ports giving access to the Canadian interior ; and their economic conditions are different from those of the New England States farther south.
The third region comprises the lowlands on both sides of the St. Lawrence, between the Laurentian Plateau on the north and the Appalachian mountains on the south, and the Ontario peninsula may also be included within it. The whole of this region is over lain with glacial debris or river deposits, and it is relatively flat, fertile, and suitable for cultivation. Its climate is intermediate
between that of the maritime provinces and that of the continental interior, and many of its products occur throughout the whole region. The St. Lawrence is one of the most important factors in its economic development, and binds its various parts together.
The next region, which may be called the Winnipeg Basin, lies east of the Cordillera and west of the Laurentian Plateau. Its northern boundary may be provisionally defined as lying in the belt of country, north of the 54th parallel, which separates the agricultural regions of central Canada from those regions further north where, because of the lack of a sufficiently long summer, cultivation is impossible except in specially favoured localities. The whole of this area has been covered with glacial drift or has formed the floor of glacial lakes. Its topography is flat in the east, undulating in the west, and hilly only in places. Its climate is extreme, its rainfall limited, and its vegetation is that of an unforested or only slightly forested country. North of the intermediate belt, lie the Athabasca-Mackenzie Plains with their generally flat physical features, their cold winters but fairly warm summers, and their forest vegetation.
In the Cordilleran region physical features form the best basis for the division of the country into natural regions. In the north is the basin of the Yukon with its low temperature, scanty vege tation, and great mineral wealth. Further south is the interior plateau of British Columbia, bordered by high mountains, and separated from the Yukon in the north and the Columbia plateau in the south by the coalescence of irregular ranges. The tempera ture is higher than in the Yukon, the rainfall is greater than south of the international boundary, and, although the region is not homogeneous, it may for present purposes be treated as one.