Continental drift is the movement of the Earth's
continents relative to each other by appearing to drift across the ocean bed. The speculation that continents might have 'drifted' was first put forward by
Abraham Ortelius in 1596. The concept was independently (and more fully) developed by
Alfred Wegener in 1912. The theory of continental drift was superseded by the theory of
plate tectonics, which builds upon and better explains why the continents move.