Learn about how the continents move and how they started out as one landmass.
In 1912, a German geologist, Alfred Lothar Wegener (1880-1930) theorized that the continents had drifted or floated apart to their present locations and that once all the continents had been a single land mass near Antarctica, which is called Pangaea (from the Greek word meaning all-earth).
Pangaea then broke apart some 200 million years ago into two major continents called Laurasia and Gondwanaland. These two continents continued drifting and separating until the continents evolved their present shapes and positions.
Wegener's theory was discounted but it has since been found that the continents do move sideways (not drift) at an estimated 0.75 inch (1.9 centimeters) annually because of the action of plate tectonics.
American geologist, William Maurice Ewing (1906-1974) and Harry Hammond Hess (1906-1969) proposed that the earth's crust is not a solid mass, but composed of eight major and seven minor plates that can move apart, slide by each other, collide, or override each other. Where these plates meet are major areas of mountain-building, earthquakes and volcanoes.