Continental mobility was important also to Hamilton's research in western North America in the 1960s, at a time when lateral motions were rejected by most northern hemisphere geoscientists.
In the late 1960s, geophysicists working with new technologies of marine magnetic surveying and earthquake seismology proved the operation of seafloor spreading, devised explanations with the new concepts of plate tectonics, and showed that ocean floors and mobile continents jointly formed tectonic plates.