Ffestiniog, Gwynedd: Thirty years ago, the Llech Ronw lay unheralded by a stream. These days, alas, it is surrounded by wire and concreted into a plinth
To Cwm Cynfal on a bright spring evening, in search of a stone I’d first seen 30 years ago. Back then, I’d asked directions to it of a woman chopping wood outside Bryn Saeth. “Dacw, yn y gornel ym mhen pella’r maes,” she’d told me. “Over there in the far corner of the field.” I crossed to the wood’s edge. A stream cascaded over mossy slabs confettied with wood anemones. Prone among drifted oak leaves was an inches-thick slate, four feet long, a shaped round hole in it. Llech Ronw (the slate of Gronw)! Quartz rocks scattered around suggested a ritual site.