Barbara Jane McCutchins age 11 Milwaukee, WN
Were the continents once all together?
Mountains grow and wear away, rivers change their courses, Some experts believe that even the great continents are always changing. But there is no proof of this, so we can only state it as a theory. One theory suggests that the land masses of the earth were once all in one piece. And there is much evidence that it was so.
Your atlas shows the shape of the great continents. Notice how some of the‑edges look as though they could fit together like a jig‑saw puzzle. This is very plain along the coastlines of Africa and South America. The land masses are thought to be layers of light rocks floating on the surface of heavier rocks. Through the ages one huge land mass may have broken up and drifted apart. This is the theory of Continental Drift.
A new idea suggests that such a break up may have been caused by radioactivity in the earths crush. The heat may have caused the lighter land area to break up and drift away into separate land masses. There is much evidence to support this theory though so far no one has been able to prove it.