3 pits worked by water power.**
Publications (1)
- Richards, Alun John (1991); Gazeteer of the Welsh Slate Industry, A; Gwasg Carreg Gwalch 978-0863811968
Taldrwst - 141m
Fronlog - 315m
Tyddyn Agnes - 366m
Twll Llwyd - 399m
Singrig - 565m
Twll Coed - 565m
Tanrallt - 669m
Plas Du - 706m
Ty'n y Llwyn - 713m
Ty'n y Weirglodd - 941m
Bryn Castell - 1,027m
Ty Mawr West - 1,079m
Ty Mawr Green - 1,115m
Nantlle Vale - 1,250m
Coed Madog - 1,299m
Twll John Fowc - 1,386m
Cloddfa'r Coed - 1,515m
Gwernor - 1,561m
Cornwall - 1,623m
Pwll Fanog - 1,698m
Gwernor - 1,739m
Tal y Sarn - 1,804m
Llwyd Coed - 1,882m
Dorothea - 1,976m