in reference to granite strata in eastern Canada, 1854 (Sir W.E. Logan and T. Sterry Hunt), named for the Laurentian Mountains (where it is found), which are named for the nearby St. Lawrence River (see Laurence). Hence, Laurasia. The Laurentian library in Florence is named for Lorenzo (Latin Laurentius) de' Medici.
updated on October 10, 2017