Slate industry in the Nantlle Valley

The men at that time took contracts from the landowners, paying two guineas per annum for the privilege of quarrying slates.

Slate roofing tiles have been excavated at Segontium Roman camp in Caernarfon and are thought to have originated in the Nantlle Valley.

This move was met with fearsome opposition, not least from one John Evans who was concerned that enclosure around the Cilgwyn quarries would affect his own interests, particularly over a dam and watercourse that he had constructed on Crown land in 1816.

The petitioners claimed that their cottages had been built over forty years earlier, that originally the land had been too wild for cultivation, and that they had improved it by hard work.

[citation needed] There were considerable difficulties involved in raising slate from the pits and in keeping them free from water, and the ingenious ways which were found to solve these problems, including blondins, chain inclines, powered rail inclines and vast revetments, are some of the principal reasons why the slate quarrying remains in this area, many of which are unique, are so important.

[4] Cilgwyn quarry installed a water-powered rail incline in 1825, to help remove fallen rock from a pit - one of the first recorded uses of this technology.

[4] Slate from the quarries was transported to the major local shipping point at Caernarfon by pack horse.

The chief engineer was George Stephenson and construction was overseen by his son Robert, assisted by John Gillespie.

[9] Cilgwyn quarry was the only one that shipped slate out via both the Nantlle and North Wales Narrow Gauge Railways.