The motion of tectonic plates has resulted and still results in the movement of the continents.
Plate tectonic reconstructions from early to late Ordovician can be seen in the quick time video. These reconstructions are based on paleomagnetic results from many continents.
There were six to eight major plates during the Ordovician that were comparable in size to modern plates. The rates of plate motion were also similar to modern rates of plate motion. Laurentia was the fastest moving continent travelling eastward at rates of 15cm/y during Early and Middle Ordovician (Scotese et al. 1991).