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Industry - The Welsh Slate Areas 

The Arfon Slate AreaRef: XD35/34: Sale of Tanybwlch Farm and Tanybwlch Bach properties

The slate beds of Caernarfon stretching from the area from Bethesda via Llanberis, Moel Tryfan and Nantlle to Penygroes are of Cambrian formation, and include two of the largest quarries in the world, namely the Dinorwig and Penrhyn Quarries that are on opposite sides to the Elidir Fawr. Whilst on the opposite side of the valley to Dinorwig, above Llyn Padarn, the Glynrhonwy Quarries are found. Six miles south-west from Llanberis are the quarries of the Nantlle Valley, where the slate outcrops on the floor of the valley, and whilst the quarries at Penrhyn and Dinorwig are worked in open terraces, at Dorothea and Penyrorsedd Quarries they are worked in deep pits.

The Merionydd Slate Area

Porthmadog HarbourThe most important slate beds of the Ordovician rocks are to be found around the Blaenau Ffestiniog area, and since the slate formations in Meirionydd generally dip deep under the mountains, the slate is mined. To the north-east of Blaenau Ffestiniog are the old quarries at Penmachno and Dolwyddelan. Other commercial slate producing areas of this period occur in the area from Cricieth and Porthmadog, right, to the south-west, running towards the River Conwy near Trefriw in the south-east.

Slate in Anglesey

In the past, roofing slates from this period were also quarried in Anglesey during the 1870's at the North Anglesey (Point Aelianus) Slate and Slab Quarry (known locally as Chwarel Sglaets) and from the Baron Hill Slate Quarry near Llanfechell.

Some other areas

Slate quarrying also was undertaken at Cedryn and Cwm Eigia, in the Conwy Valley, and at Clogau, Foel Faen and Glyn Ceiriog , Denbighshire. The Berwyn or Clogau Quarry near Llangollen that dates back to the 1770's is still in production.

The Slate Industry of the South West.

Most people regard the slate industry as being synonymous with the northern areas that dominates slate production, producing between 80%-90% of slate in the countries of Britain at its industrial peak. But one cannot disregard the industry in North Pembrokeshire, on the boundary with Carmarthenshire and in the Cilgerran region in Dyffryn Teifi.

During the second half of the nineteenth century we read of around 100 quarries in this area employing hundreds of workers.

Quarrying history here also dates back to the time of the Romans, and slates were used centuries later for roofing churches. Indeed it is claimed that slates from this area were used in the twelfth century to roof the abbey at Whitland.

Slates were exported to Bristol and Ireland in 1566 and George Owen rports that in 1603 slates were exported from Haverfordwest, Tenby and Pembroke. The Cambro-Irish links were further developed when 40,000 slates were exported to Ireland in 1616 from various ports, whilst in 1639 30,000 slates were exported from Fishguard alone.

It is true that by the eighteenth century the quarries of Devon and Cornwall were claiming more and more of the Bristol Channel trade to Ireland, but the greatest challenge to the industry in south west Wales was the flooding of the Irish market by the north Wales quarries. But despite this and the fact that the quarries were isolated from the populous areas of England, industrial development in the south gave fresh impetus to the quarries.

However revitalisation was not going to be long lived. By 1876 another period of decline had set in. By 1884 slate prices had fallen to the levels of 1860 and Pembrokeshire slate became unfashionable. The situation improved by the 1890's but by then only a few quarries had survived the depression.

But on the other hand the fate and reputation of the green slate was to fare better in the twentieth century

University College, Bangor, (c) National Slate Museum, LlanberisThe new buildings of the University College of Wales, Bangor in 1907 were to be roofed with green slate. Since the green slate quarries of Dyffryn Nantlle were not in production green Pembrokeshire slate was used; a decision that was not popular in the Bethesda area at the time! By the 1920's and 1930's the blue-grey slate was regarded as being unfashionable by architects and Davies Bros of Porthmadog was supplying Pembrokeshire Green to builders of the area. Indeed the green slate quarries of Dyffryn Nantlle were in production by 1910 to meet the increased demand.

The Gilfach Quarry to the east of the River Cleddau produced green slate for roofing purposes until 1987. 


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