Wegener thought that the continents were moving through the earth's crust, like icebreakers plowing through ice sheets, and that centrifugal and tidal forces were responsible for moving the continents.
On top of that, Wegener learned that related species, too small to swim the oceans, were found on different continents, as were similar fossils. ... The year after Wegener died, Arthur Holmes published his idea that thermal convection in the earth's mantle could cause continents to move.
