RIVER BASINS. COASTS.
Do not copy the sketches given in these lessons. They are but suggestions to you, who will be able to express your own thoughts and represent your own mental pictures better than you can another’s. They are given to show you that simple sketches will help a child to a clearer understanding of the subject under consideration. As has been said elsewhere, all such illustrations should be drawn as they are needed to illustrate a given point in the development of a lesson; for they carry more weight than if sketched beforehand, that is, outside of the class exercise.
To merely locate in your sketch a house, spring, tree or man, will often be of great value to the pupil, though you may feel timid about trying to draw it, or think you have not the time. The experience of many teachers in this respect may be illustrated by supposing a case.
A sketch is to be drawn, including the figure of a man, animal or any object which has been considered difficult and therefore somewhat avoided.
The teacher, by one or two rapid strokes in the right direction, indicates the location and movement of this figure, and proceeds with the lesson without any hesitation or laborious attempts to really sketch it. The next time it is necessary to represent it (perhaps in the second or third lesson), sufficient confidence and skill have been gained to encourage additional strokes in the development of form, and every succeeding attempt has resulted in the addition of details of structure, until almost without knowing it, the necessary skill has been acquired to make an adequate sketch. How? Bydoing, the teacher has been forced to form the mental picture, which, once acquired, can be represented, though it may be more or less crudely at first.
52 53 54 55 56
52 53 54 55 56
Fig. 50illustrates the basin of a young river or brook, with its slopes and system of drainage, just such an one as may be seen near many country school-houses, and an exaggerated type, only, of what may be found in the streets and alleys of the city. Its source (a) is found in a slight depression which, in the spring or after heavy rains, becomes a pond, from which its waters overflow and trickle down through two channels, which they have worn for themselves. The soil brought down by these rivulets and others which are tributaries to the main stream, may be seen deposited atb,c,d,e, as flood plains, islands, and delta. Notice the cañon cut by one of the tributaries through the left slope of the basin, and the cascade and waterfall where the debris brought down at high water has formed an obstruction. InFig. 51is given a typical Switzerland river basin.Figs. 52 to 55inclusive, show ocean wearing and rock weathering. “Hilt Rock” (Fig. 52) shows alternate layers of trap rock and sandstone. InFig. 53(“Point Portal,” Pictured Rocks, Lake Superior), is seen the effect of wave and wind wearing in soft rock, andFig. 54(“Land’s End,” Cornwall, England), is an example of wave wearing in hard rock.Fig. 55(“Giant’s Cause-way,” Ireland), shows the weathering and wearing of basaltic rock.Fig. 56is Eddystone Light-house, (England).
57 58 59 60
57 58 59 60
In the drawing of maps, the meeting of land and water can be as accurately drawn by the new method as by the old. The following sketches illustrate the fact that it is not necessary to use any line running contrary to the general direction of surface, in order to represent any contour of coast.
Figs. 57 to 60are imaginary bird’s-eye views of coasts.Fig. 57shows a stretch of level land at the coast, with broken or hilly land between it and the distant higher hills or mountains: the latter being merely suggested in the representation. A stream winds its way through the low land to the ocean, where the silt which it has brought down and the sands which have been washed up by the sea, form a delta and sand-bars.Fig. 60shows drowned valleys, fiord coasts, and continental islands.