Continental drift orogeny at the boundaries of convection cells. By 1967, barely two decades after discovery of the mid-oceanic rifts, and a decade after discovery of the striping, plate tectonics had become axiomatic to modern geophysics. In addition, Marie Tharp, in collaboration with Bruce Heezen, (who initially ridiculed Marie's observations that her maps confirmed continental drift theory), provided essential corroboration, using her skills in cartography and seismographic data, to confirm the theory. Evidence for the movement of continents on tectonic plates is now extensive. Similar plant and animal fossils are found around the shores of different continents, suggesting that they were once
Continental drift apart. Although he presented much evidence for continental drift, he was unable to provide a convincing explanation for the physical processes which might have caused this drift. His suggestion that the continents had been pulled apart by the centrifugal pseudoforce ("Polflucht") of the Earth's rotation or by a small component of astronomical precession was rejected, as calculations showed that the force was not sufficient. The Polflucht hypothesis was also studied by Paul Sophus Epstein in 1920 and found to be implausible. The theory of continental drift was not accepted for many years. One problem was that a plausible driving force