The naming of the firth after Lorn, a major province on its eastern shore, reflecting the geopolitical power distribution of the times, became less apt as Lorn receded and disappeared. Much of Lorn bordered Loch Linnhe, a fiord to the north that, for whatever reason, escaped being included in the firth. Moreover, the firth extended far to the south of Lorn. To some writers, the name was to be extended south to Colonsay, but to others it went only as far south as the Garvellachs. The official maps of the British Empire did not resolve the exact borders of the firth. Admiralty chart 2724, mapping the coast from the North Channel, places the label, “Firth of Lorn,” on only the narrowest part of the firth, leaving the reader to guess how far south it applied, and the concomitant Ordnance Survey map follows the same convention. The waters between the open Atlantic to the north of the North Channel and the named inner firth are an undefined and unnamed lagoon.