The theories of continental drift were extremely controversial when first introduced by Alfred Wegener circa 1920. Wegener showed that the Americas and Africa fitted together nicely and suggested that continents move. Alas, his rationale for how this might occur wasn't correct and he was lambasted by the scientific establishment of the time, particularly by Cambridge geophysicist Harold Jeffreys, and the entire concept of continental drift was discredited. It was not until the 1960s and 1970s that ideas of continental drift came to be accepted as the norm, when new theories of plate tectonics were advanced.