NATURAL FEATURES OF INTEREST IN NORTH AMERICA.
It is the constant, persevering attempts—simply the continual doing—that accomplishes the work of the world. Devote ten minutes a day, if you cannot spare more time, to your preparation for sketching in to-morrow’s classes. By expressing your mental picture again and again you clear it up, and the increased interest of your pupils in the work will be ample reward. The experience gained will probably show that your last attempt is a much more complete expression than the first one; the repeated efforts made having resulted in a more thorough knowledge of the subject and therefore, a more complete representation.
As before stated in connection with the study of North America, natural features of interest should be sketched while with the class, at the same time locating them on the map.
The mental images for such sketches, as well as for all others, if not gained by actual observations, must be acquired through the study of pictures and descriptions, as has been remarked before, and should not be copied line for line from another’s sketch.
69 70 71 72 73
In [Fig. 65] (entrance to Mammoth Cave, Kentucky) the stratification of the rocks is seen back of the entrance, within it, and at the right in the rocks of the foreground. (It is estimated that 12,000,000 cubic yards of limestone have been worn away or displaced in the excavation of the interior of this celebrated cave.)
[Fig. 66] (Natural Bridge, Virginia) also plainly shows the stratification of rock. What is the character of the rock? What was the agency employed in the sculpturing of both of these natural wonders?
In [Fig. 67] (Niagara Falls) the general direction of the mass is oblique. Notice how the water breaks as it falls, owing to the resistance of the atmosphere. In the “Palisades on the Hudson” ([Fig. 68]) notice the debris at the foot of the vertical wall of stone, forming what is called the talus slope. This is mostly overgrown with vegetation. In [Fig. 69] (a gorge in the cañon of the Colorado) the stratification of rock and the almost vertical cliffs are the principal features illustrated. [Fig. 70] represents a lofty peak in one of the cañons along the line of the Colorado. [Fig. 71] (Devil’s Slide, Weber Cañon, Utah) shows the mountain side as worn back leaving the trap rock projecting. (How came the harder rock there in this peculiar shape?) [Figs. 72 and 73] are geysers in Yellowstone Park—“Old Faithful” and “the Sponge.” In the latter, notice the corrugated formation, and the little stream that flows from its base.
