Chwarel Ty'n-y-coed is located a short distance to the north-east of Arthog. It is a terraced hillside quarry which opened in the mid-eighteenth century. It operated on several levels connected by inclines. The lowest level was developed into a pit accessed by a short tunnel. Dressing was originally carried out by hand on the terraces, but later a tramroad took material across the main road , possibly to a mill, and through a short tunnel to a trackway down to a small jetty. This was replaced by an incline and tramroad, later extended to a railway siding. In 1868 a substantial mill, probably for sawing only, was built. But the quarry closed the following year.
On the terraces there remain much decayed vestiges of dressing sheds, drumhouses, weigh-houses etc. The quarry was later used for dumping rubbish and the tramroad for this purpose is a prominent feature. Other features which survive (1991) include fine drystone tramroad embankment to the mill, a smithy (possibly a pre-existing house), the dated mill, and stone incline formation to the railway.
The quarry portrayed as disused on OS County series (1889), but with some infrastructure, notably tramway to Mawddach estuary, intact.
Sources:
A.J.Richards, A Gazeteer of the Welsh Slate Industry (1991), p.155.
OS first edition 25-inch map: sheet Merionethshire XXXVI.8.

David Leighton, RCAHMW, 12 January 2015