Note 3175 — BOOK IV. AN ACCOUNT OF COUNTRIES, NATIONS, SEAS, TOWNS, HAVENS, MOUNTAINS, RIVERS, DISTANCES, AND PEOPLES WHO NOW EXIST OR FORMERLY EXISTED.
John Bostock translation
Meaning Gessoriacum, the present Boulogne. He probably calls it Britannicum, from the circumstance that the Romans usually embarked there for the purpose of crossing over to Britain.