1. The slate quarry north-west of Geufron, on a hill overlooking Ysbyty Ystwyth from the west, is a series of natural shale and mudstone outcrops which produce excellent splitting qualities for the provision of thin slates. Today the quarry is used for the occassional supply of hardcore for local farmers but historically the quarry has been remembered as a source of roofing slates for local buildings. The outcrop of Craig y Ogof to the west, currently in forestry at SN 701715, was a documented source of slate for the Trawsgoed Estate c. 1800.

Field visit to the quarry to research sources for the roofing slates found at Abermagwr Roman villa with Jeff Davies and Chris Fletcher, 20th March 2012.

T. Driver, RCAHMW

2. The outcrop is clearly depicted as a 'Slate Quarry' on Nantbir Common in the 1781 Crosswood Volume 1, Map of Nant Bir Ucha in the Parish of Gwnnws (map 16NW). The volume is held by the National Library of Wales (094/9/2).

T. Driver, RCAHMW, 2016