In our solar system Mercury, Jupiter, Saturn , Uranus, and Neptune all also have magnetic fields. None of them have plate tectonics. Therefore any notion using the magnetic field of plate tectonics is unsound. a magnetic field is evidence of a liquid core that could possibly drive plate tectonics but it is not in itself evidence that is occurring.
Remains of Mesosaurus, a freshwater crocodile-like reptile that lived during the early are found solely in Southern Africa and Eastern South America. It would have been physiologically impossible for Mesosaurus to swim between the continents.
