<P> Pangaea or Pangea ( / pænˈdʒiːə / ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras . It assembled from earlier continental units approximately 335 million years ago , and it began to break apart about 175 million years ago . In contrast to the present Earth and its distribution of continental mass , much of Pangaea was in the southern hemisphere and surrounded by a superocean , Panthalassa . Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists . </P>
what land mass was north america a part of about 300 million years ago
Pangaea