What do you understand by the theory of continental drift? Discuss the prominent evidences in its support. (UPSC 2013)

Continental drift theory, proposed by Alfred Wegener in 1912, states that present continents were once joined in a single supercontinent, Pangaea, and later drifted apart. Its main evidences are the jigsaw fit of continental margins, especially South America and Africa; continuity of rock belts and mountain chains across oceans, such as the Appalachians and Caledonians; identical fossils like Mesosaurus, Lystrosaurus and Glossopteris on separated southern continents; and matching glacial tillites in India, Africa, Australia and Antarctica. These lines of evidence support past continental mobility, later better explained by plate tectonics.