A Black Mountain (Mynydd Du) spate stream running south through Brynamman and Glanamman to join the Loughor at Pantyffynnon. A genuine sea trout river — the brown trout population itself leans heavily on the sea-trout life history rather than standing alone — with a late-season salmon run that's stronger in the lower river than the upper. Anthracite mining, tinplate and chemical works have left a legacy of elevated copper and zinc, and current storm-overflow data shows frequent, sustained sewage discharges around Brynamman, Glanamman and Ammanford — an honest caveat alongside the genuine fishing. No grayling: absent from the Grayling Society's own regional guide, consistent with the river's non-limestone, upland-spate character.
- Carboniferous coal measures
