“Mae gan Dirwedd Lechi'r Gogledd-orllewin dreftadaeth ddaearyddol, gymdeithasol, economaidd a diwylliannol gyfoethog, a dywedir mai'r ardal hon o Wynedd wnaeth doi adeiladau'r byd yn y 19eg ganrif, gyda chyflenwadau aruthrol o lechi o'r ardal yn cael eu hallforio ledled y byd.
“The Slate Landscape of Northwest Wales is rich in geological, social, economic and cultural heritage, and it’s said that this area of Gwynedd roofed the 19th century world, with huge amounts of slate mined in the area and exported internationally.