Laurasia Laurasia Laurasia () was the more northern of two supercontinents (the other being Gondwana) that formed part of the Pangaea supercontinent around (Mya). It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pangaea, drifting farther north after the split. The name combines the names of Laurentia, the name given to the North American craton, and Eurasia. As suggested by the geologic naming, Laurasia included most of the land masses which make up today's continents of the Northern Hemisphere, chiefly Laurentia, Baltica, Siberia, Kazakhstania, and the North China and East China cratons. Although Laurasia is known
Gondwana During the Devonian giant club mosses replaced the Baragwanathia Flora, introducing the first trees, and by the Late Devonian this first forest was accompanied by the progymnosperms, including the first large trees "Archaeopteris". The Late Devonian extinction probably also resulted in osteolepiform fishes evolving into the amphibian tetrapods, the earliest land vertebrates, in Greenland and Russia. The only traces of this evolution in Gondwana are amphibian footprints and a single jaw from Australia. The closure of the Rheic Ocean and the formation of Pangaea in the Carboniferous resulted in the rerouting of ocean currents which initiated an Ice House period.