The road from Dyffryn Nantlle slants across a hillside pocked with 19th-century copper-mine workings, waste from which still mars the valley floor. A wide, marshy col above – Bwlch Gylfin (Pig Pass) – has a dramatic, quartz-seamed rocky knoll, Clogwyn y Garreg. Welsh folklore identifies this as a portal to fairyland. Beyond it are Cwellyn and the Gwyrfai valley, which abound in associations with those identified in Welsh by the propitiatory name Tylwyth Teg – (Fair Folk).
Early Ordnance Survey maps show two dammed lakes at Bwlch Gylfin. Llyn Bwlch y Moch is now no more than a sedgy bottom. Sluices ran from the now-breached dam to power machinery down-valley. Llyn y Dywarchen’s dam, however, is still intact. For centuries, the lake’s floating island was a major attraction. In 1188, Giraldus Cambrensis noted how it was “driven from one side to the other by the force of the wind”. In 1698, the astronomer Edmund Halley swam out to check that it did indeed float. Thomas Pennant in 1784 reported that cattle occasionally wandered onto it and were carried away from the shore.
Better still was the experience one evening of a young man from Drwsycoed farm, who found a fairy woman of great beauty reclining there. She agreed to be his servant if he could discover her name, which he did by eavesdropping on a fairy conversation as he returned from market. It was Bela, and she proved expert at animal husbandry. Their flocks thrived. She agreed to take the lad as husband on condition he never touched her with iron. Children were born. (Their descendants migrated beyond the Ridge of the Red Cairns by way of the Pass of the Two Biers into Cwm Pennant, where they were known as Belisiaid.)
Inevitably, the catastrophic day came when he carelessly tossed her a bridle and she vanished instantly into the lake. In one version of the story, Bela’s mother enabled her nightly return to the floating island for as long as her husband lived. He and the island are long gone into the realm where folklore, travellers’ tales and prehistory all mingle. Now even the resident teal have rejoined their estuarine winter flocks, as ice fingers out from lake shallows to still the lapping waves.