The group of Penmon Quarries, including Flagstaff (NPRN 40625) and Dinmoor (NPRN 400585), have been worked since the sixteenth century and they later provided the stone for Telford's bridges. Penmon Park Quarry advertised it's stone as 'Anglesey marble' and in 1996 there were roofless remains of a large steam powered mill at the foot of an incline, and a pier.

Source: David Gwyn & Merfyn Williams (1996) `A Guide to the Industrial Archaeology of North West Wales?. Association for Industrial Archaeology

Claire Parry, RCAHMW, 1 November 2011.