A slate quarrying valley, frozen in time
The valley of Cwmystradllyn is a peaceful setting for walkers in the shadow of the Moel Hebog and Moel-Ddu mountains. Quiet contemplation would not have been possible in the 1850s and 1860s, when a flurry of slate-quarrying activity brought the hum of heavy industry to the area.
Gorsedda Slate Quarry was in operation for only two decades, as the slate here was found to be not worth quarrying. However, this has left us with some fantastic remains of mid-19th-century quarry life. Gorsedda is a classic example of a quarry where the rock was worked in stepped benches known as ‘galleries’.
The quarry was connected by railway in 1856, using a system involving horses and gravity – the work of a Scottish engineer, James Brunlees. This system transported slate to a mill at Ynysypandy and on to the harbour at Porthmadog by horses. The conserved mill is worth a look – the multi-level building turned the freshly quarried slate into dressed slabs, used, for example, as gravestones. You will also notice the overhanging wall at the quarry, which was built to prevent slate waste from sliding onto the tramway.
The deserted village of Treforys overlooks a lake and was built for the quarrymen in 1856. You will be able to see the ruins of 36 cottages, all that remains of this settlement on the hillside.
Minor roads off A487 signposted Golan / Cwm Ystradllyn and Cwm Pennant
Porthmadog - 6 miles
Nearest bus stop at Bryncir Woollen Mill
Small car park located at SH 556441 and limited roadside parking for Ynys y Pandy slate mill. Very limited parking at roadside by Llyn Cwmystradllyn. Car park at SH 541491 for Cwm Pennant (Prince of Wales) Footpaths. Walking boots recommended. OS map essential. Dogs must be on lead.
Full Grid Reference - Cwmystradllyn slate mill: SH 550433, Gorseddau Quarry: SH573453, Treforys village: SH559452
OS Landranger map sheet: 115,124
- Cwmystradllyn and Cwm Pennant Slate Landscape, Cwmystradllyn, LL51 9BQ