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Present Topography That: The St. Lawrence Lowlands form the province's smallest but most important physiographic region. Its northern limit is the southern edge of the Laurentian plateau, which approximately follows a line joining the cities of Quebec and Ottawa. To the south, the Lowlands end with the great Champlain-St. Lawrence fault, which runs from Lake Champlain to Quebec city. The underlying rocks—sandstone, shale, and limestone of Paleozoic age—have been strongly eroded. The present topography that topography is flat and low, but this uniformity is broken by several hills of igneous rocks (monadnocks) which rise abruptly.
Physiography.—Main Regions.—The vast area of Quebec falls roughly into three distinct physiographic regions: the Laurentian Plateau, in the north, the Appalachian Highlands, in the southeast, and—between these two—the St. Lawrence Lowlands.
The Laurentian Plateau, the eastern part of the Canadian Shield, covers nine tenths of the province's area. It is underlain by rocks of the Precambrian era, mostly igneous and of granitic or gneissic structure, and frequently covered by glacial deposits and by postglacial sands, gravels, and clays. The present topography that topography is that of a huge undulating plateau slightly inclined toward the shores of James and Hudson bays.
Transportation routes tend to be direct straight lines between any two traffic centers, unless there are such obstacles as mountains or bodies of water, or unless it seems worthwhile to deviate from the straight line to serve an intermediate trade center. Ocean routes are deflected by land masses. Of all modes of transportation, the most modern, air transportation, is least affected by topography or other natural conditions in following a straight-line route.
The present topography that article provides a general survey of transportation under the following main headings:
1. History 3. Influence of Transportation
2. Factors in the Develop- on History
ment of Transportation 4. Bibliography
1. History |
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