Open quarry producing slab.*

The original site features a shallow pit, rubbish runs, and some buildings of uncertain function. The later site shows evidence of excavation, walling, and a possible adit. The incline has largely collapsed, but at its foot stands an unusual mill building, now in reuse, with a wheel pit and stone-lined leat still visible. Other agricultural buildings survive nearby, one of which may have housed the steam mill.

This open quarry dates from the 18th century and primarily extracted slate slabs, which were likely transported by horse sledge to a shipping point near the pre-Cob tidal estuary. By the mid-19th century, operations had shifted to SH578408, possibly incorporating some underground working. Material was transported by incline to a water-powered mill near the road, though steam power was later adopted due to limited water supply. The product was Tremadoc Grit, an exceptionally hard rock used for slabs, particularly steps and thresholds, which were carted to Porthmadog.