|
 |
 |
|
Present Topography Flat: 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 flat topography is flat and low, but this uniformity is broken by several hills of igneous rocks (monadnocks) which rise abruptly.
Rule for Tempering Pianos and Organs.— Tune middle C to desired pitch, then tune F— fifth below—sharp of C, until between C and F, there result three beats in five seconds. Next tune A-sharp — fourth above F-sharp of the latter, until there results one beat, each second. Next tune G—fourth below middle C — flat of C, by one beat a second; then tune D — fifth above — flat to G, by three beats in five seconds; A — fourth below — flat to D; E — fifth above — flat to A; B — fourth below — flat to E; F-sharp — fourth below — flat to B; C-sharp — fifth above — flat to F-sharp; G-sharp — fourth below — flat to C-sharp ; D-sharp— fifth above — flat to G-sharp, which will make D-sharp as sharp of A-sharp, as the latter is sharp of the first F tuned.
In their upper reaches, the more resistant bands of rock form waterfalls and rapids in the narrower parts of the valley. If the rocks are lying horizontally, the topography developed is characterized by flat-topped hills [7]. But if the beds are tilted, scarpland topography is produced, in which the more resistant layers form cuestas whose steeper sides face up the inclination (dip) of the rocks and vales are worn out on the outcrop (strike) of the softer beds [8]. The trel-lised drainage pattern may undergo minor changes.A particular river, perhaps because it has more powerful springs at its source, or greater runoff from the valley sides, or a shorter course to the sea, may cut down the level of its valley Floor more quickly than its neighbour and eventually capture it [11]. |
|
|
| |
|
|
|
|
