Cape Noun
Mare Tenebrosum
Mare Tenebrosum meaning Sea of Darkness is an ancient name for the Atlantic Ocean(a). According to Michael Hübner, Cape Noun south of Agadir was originally the start of Mare Tenebrosum as it was dangerously shallow and muddy.
(a) Saudi Aramco World : Pillars Of Hercules, Sea Of Darkness (archive.org) *