Laurentian Look up Laurentian at Dictionary.com
in reference to granite strata in eastern Canada, 1863, named for the Laurentian Mountains, where it is found, which are named for the nearby St. Lawrence River. Hence, Laurasia, Paleozoic supercontinent comprising North America and Eurasia, 1931, from German (1928), from Laurentia, geologists' name for the ancient core of North America + (Eur)asia.