He noticed that:
* Matching geological formations: Identical rock types and fossils were found on continents now separated by vast oceans.
* Matching fossil distributions: Fossil remains of the same species were found on continents that were seemingly too far apart to have been connected.
* Fit of the continents: The shapes of continents like South America and Africa seemed to fit together like puzzle pieces.
Wegener's theory proposed that all the continents were once joined together in a supercontinent called Pangaea, which then gradually drifted apart over millions of years. While initially met with skepticism, his ideas paved the way for the development of the theory of plate tectonics, which is now widely accepted.
