Note 2882 — BOOK IV. AN ACCOUNT OF COUNTRIES, NATIONS, SEAS, TOWNS, HAVENS, MOUNTAINS, RIVERS, DISTANCES, AND PEOPLES WHO NOW EXIST OR FORMERLY EXISTED.
John Bostock translation
It has been suggested by Brotier that Pliny here refers to the Icy Sea, but it is more probable that he refers to the north-eastern part of the Baltic, which was looked upon by the ancients us forming part of the open sea.