linguistic:voice_change, quality:corruption, structural:scholar_edition, linguistic:paraphrasing, linguistic:translation
Continental drift theory

Wegener first thought of this idea by noticing that the different large landmasses of the Earth almost fit together like a jigsaw puzzle. The continental shelf of the Americas fits closely to Africa and Europe. Antarctica, Australia, India and Madagascar fit next to the tip of Southern Africa. But Wegener only published his idea after reading a paper in 1911 which criticised the prevalent hypothesis, that a bridge of land once connected Europe and America, on the grounds that this contradicts isostasy. Wegener's main interest was meteorology, and he wanted to join the Denmark-Greenland expedition scheduled for mid-1912. He presented his continental drift hypothesis on 6 January 1912. He analysed both sides of the Atlantic Ocean for rock type, geological structures and fossils. He noticed that there was a significant similarity between matching sides of the continents, especially in fossil plants.

From 1912, Wegener publicly advocated the existence of "continental drift", arguing that all the continents were once joined in a single landmass and had since drifted apart. He supposed that the mechanisms causing the drift might be the centrifugal force of the Earth's rotation (" Polflucht ") or the astronomical precession. Wegener also speculated about sea-floor spreading and the role of the mid-ocean ridges, stating that "the Mid-Atlantic Ridge... zone in which the floor of the Atlantic, as it keeps spreading, is continuously tearing open and making space for fresh, relatively fluid and hot sima from depth." However, he did not pursue these ideas in his later works.

In 1915, in the first edition of his book, Die Entstehung der Kontinente und Ozeane, written in German, Wegener drew together evidence from various fields to advance the theory that there had once been a giant continent, which he named " Urkontinent " (German for "primal continent", analogous to the Greek " Pangaea ", meaning "All-Lands" or "All-Earth"). Expanded editions during the 1920s presented further evidence. (The first English edition was published in 1924 as The Origin of Continents and Oceans, a translation of the 1922 third German edition.) The last German edition, published in 1929, revealed the significant observation that shallower oceans were geologically younger. It was not translated into English until 1962.

Note prior advocates for various forms of continental dynamics: Abraham Ortelius, Antonio Snider-Pellegrini, Eduard Suess, Roberto Mantovani, Otto Ampferer, and Frank Bursley Taylor.