. The continents fit together like the pieces of a puzzle. Here the fit has been made along the continental slope at the depth of 910 meters, or 500 fathoms (gray areas). Within the present continents are ancient terrains between 1.7 and 3.8 billion years old (black areas). The close fit of the shorelines of the continents suggests that they once formed a single land mass known as Pangaea shown in Figure 4.7.
Copyright 2010, Professor Kenneth R. Lang, Tufts University