dec 23, 1915 - Plate techtonics
Wegener collected data form both his own, and Alfred Russel Wallace's studies about Biogeography to formulate his theory about plate tectonics. He theorized that because there were identical fossils on opposite sides of the Atlantic that the continents of the Americas and Europe, alone with others, had once been joined and slowly drifted apart. In the 1960's scientists were finally able to map the ocean floor and use magnetic evidence to suport his theory.
Added to timeline: