1. Pontrhythallt slate works formed one component of a milling complex the rest of which was located about half a kilometre to the north-west at Crawia (see NPRN 40534).
David Leighton, RCAHMW, 15 June 2015.

2. There were two separate slate mills at Pont Rhythallt, both served by a single leat from a weir across the Afon Rhythallt some 260 metres upstream. The upper mill was immdediately adjacent to the Padarn Railway which carried slate products from the Dinorwic Quarries to Port Dinorwic on the Menai Strait. The lower mill (there can have been little difference in altitude) was served by a railway siding from the L&NWR Llanberis branch. A further tramway connected both mills to the Crawia Slate Mills 450 metres downstream.
W J Crompton, RCAHMW, 18 October 2018.