Jackie Davis, Age 9, Of Camden, So. Car., for his question:
Were America and Africa once joined together?
The Americas are separated from Africa and Europe by the stormy Atlantic Ocean. When you look at a map, your eye follows dawn the two shorelines and you wonder. The land masses look like two parts of a jig saw puzzle that could be fitted together. Maybe, you think, they were once a larger continent which split down the middle arid drifted apart.
When a scientist cannot explain something, he may make a guess. This educated guess is called a theory. The continental drift is a theory. Many of the facts we know suggest that africa was once joined to the shores of the americas. But as yet we do not have enough evidence to prove that this was so. The theory of the continental drift is an educated guess that all the land masses were once joined but no one can prove it.
We tend to think that the face of our lovely planet does not change at all. But this is because most of the changes are so slow that we would not notice any differencr: in 50 lifetimes. Nevertheless, we know for sure that mountains rise and fall, lakes fill up and disappear, rivers change their paths, ice age glaciers creep down from the poles and lven the seas flood over the land and go back to their basins.
These big eyents take millions of years. But we know for sure that the face of our globe can change slowly it is always changing. Some experts argue that all these changes happen because the crust of the earth can move up and down land and sea areas rise and fall. These experts say that the crust of the earth never moves sideways or horizontally. The earth's crust, they say, is rigid; the continents
And seas were always in their places.
Other experts disagree. They think that the earth's crust may be sitting on a deep layer of plastic material. The deeper layer may shift and move, causing cracks in the brittle crust and moving great sections in a sideways direction around the globe. Perhaps, about 150 million years ago, all the land formed one great continent reaching from pole to pole. America and Africa, perhaps, were joined together and formed the center of this super continent, which they call Pangea. The Gulf of Mexico may have been an inland sea. Later, the land mass may have cracked down a chain of deep valleys and slowly, slowly the old world and the new world drifted apart.
Scientists are trying hard to prove whether the theory of continental drift is true or false. They are gathering facts and more facts, and a lot of the new evidence tends to favor the theory. An earthquake fault and other formations in the old world match others in the new world. The two land masses have been compared to a page of print torn down the middle. The earth's magnetism and sea beds, islands and underwater mountains, fossils and coal beds suggest that all the land was once a super continent.