The Dwyryd River Navigation (nprn 91424) consists of some seven kilometres of navigable river and includes the Cemlyn Canal and various riverside wharves or quays between Maentwrog Bridge (nprn 24191) downstream to Pont Briwet (nprn 404539). It was last used commercially in about 1873; the principal traffic was slate, but timber, limestone and coal were also carried.
The narrow canal was constructed in or shortly before 1823, it is 285m long and served Parry's wharf which shipped a limited amount of slate, but also functioned as a coalyard and boasted a limekiln and general warehouse, both of which functioned until the 1850s.

B.A.Malaws, RCAHMW, 18 August 2009.
Louise Barker, RCAHMW, December 2014

Source:
Gwyn, D. 2015. Welsh Slate. Archaeology and History of an Industry. RCAHMW.