“The continents must have shifted,” he wrote. “South America must have lain alongside Africa and formed a unified block. … The two parts must then have become increasingly separated over a period of millions of years like pieces of a cracked ice floe in water.” At one time, Wegener hypothesized, all of the present-day continents had formed one giant supercontinent, Pangaea. Wegener’s theory of “continental drift,” widely derided during his lifetime, was, of course, to a large extent vindicated by the discovery of plate tectonics.
