Sgwd Rhyd Yr Hesg (Melincourt Falls in English) very picturesque set of waterfalls near Resolven in the Vale of Neath in South Wales. They are formed by the brook plunging 80 feet over a resistant band of 'Lower Pennant Sandstone'.
They are a few miles to the South West of the main 'Waterfall Country' around Pontneddfechan, but if you are down that way, I would recommend making the detour.