One of the ways to see how contours show the shape of the ground is to pour half a bucket of water into a small depression in the ground. The water's edge will be exactly level, and if the depression is approximately round the water's edge will also be approximately round. The outline will look something like figure [6].
Draw roughly on a piece of paper a figure of the same shape and you will have a contour showing the shape of the bit of ground where you poured your water.
Next, with your heel gouge out on one edge of your little pond a small, round bay. The water will rush in and the watermark on the soil will now be shaped something like figure [7].
Alter your drawing accordingly, and the new contour will show the new ground shape.
Again do violence to the face of nature by digging with a stick a narrow inlet opening out of your miniature ocean, and the watermark will now look something like figure [8].
Alter your drawing once more and your contour shows again the hew ground form. Drop into your main pond a round clod and you will have a new watermark, like figure [9], to add to your drawing. This new contour, of the same level with the one showing the limit of the depression, shows on the drawing the round island.
Drop in a second clod, this time long and narrow, the watermark will be like figure [10], and the drawing of it, properly placed, will show another island of another shape. Your drawing now will look like figure [11].
It shows a depression approximately round, off which open a round bay and a long, narrow bay. There is also a round elevation and a long, narrow one; a long, narrow ridge, jutting out between the two bays, and a short, broad one across the neck of the round bay.