Early 17th century; earliest use found in Edward Topsell (d. 1625), Church of England clergyman and author. From post-classical Latin Scotia, the name of Scotland + -an.
Scotian2
/ˈskəʊʃ(ə)n/
adjective
Chiefly in the names of geological or geographical features: of or relating to Nova Scotia. Frequently in Scotian Shelf: the area of continental shelf adjacent to Nova Scotia.