In the latest Precambrian and early Paleozoic ,the supercontinent Rodinia, centered about the south pole, broke apart as blocks drifted northward. Most notable of these blocks were the large continents North America [Laurentia], Baltica, and Siberia.
Numerous plates and continental blocks approach North America from the south and east. The Taconic arc has just collided forming the Taconic orogeny.
Tectonics, Sedimentation, Paleogeography of North Atlantic Region
1st Order Global Tectonic Features