The shapes and positions of the continents may seem fixed at the time scale of human experience. But on old earth continents have moved, collided, merged and then been torn apart again.
Mountains have risen and been razed to the ground, oceans have formed and dried up. Valleys have been carved and so during the course of earth’s eventful history. Alfred Wegener’s theory of Continental drift proves the same idea.
Thus the shapes and positions of the continents are not fixed and permanent.