Anglesey Coalfield

Stretching from Nant and Hirdrefaig in the Pentre Berw area along Cors Ddyga ("Tygai's marsh") and under the sea at Malltraeth village which was called 'yr Iard' or 'Iard Malltraeth'.

On the western side of the Afon Cefni lies Cors Malltraeth.

[1] Working the coal on Cors Ddyga at such places as Nant, Tyddyn Mawr, Penrhyn Mawr, Gwaith Berw (New Berw Mine), Berw Uchaf and Tai Hirion took place during the coalfield's 300 year productive life from the fifteenth to the late nineteenth century.

During the early years of the twentieth century a committee was formed to reopen the coalfield at Llangristiolus but the middle class and farming gentry did not support the venture.

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