Note 2957 — BOOK IV. AN ACCOUNT OF COUNTRIES, NATIONS, SEAS, TOWNS, HAVENS, MOUNTAINS, RIVERS, DISTANCES, AND PEOPLES WHO NOW EXIST OR FORMERLY EXISTED.

So called, it is supposed, from the Celtic word Mor, which means “the sea.” Térouane and Boulogne are supposed to occupy the site of their towns, situate in the modern Pas de Calais.