Nantlle Valley

The Nantlle Valley (Welsh: Dyffryn Nantlle) is an area in Gwynedd, north Wales, characterised by its large number of small settlements.

The area is also historically important geologically, and featured in one of the most contentious disputes of the 19th century, between the 'Diluvialists' who believed in the Biblical flood, and the ‘Glacialists’, who supported the Glacial Theory, which was substantially established by studies of the drift sediments on Moel Tryfan.

Between 85-90% of the population of the Nantlle Valley speak Welsh as their first language. Some of the communities came into being as a result of slate quarrying in the late eighteenth or early nineteenth centuries and some have a history stretching back to antiquity. There are Iron Age forts at Caer Engan in Pen-y-Groes and on the coast at Dinas Dinlle and evidence of Bronze Age settlement on the higher ground. The valley was important during the Middle Ages - with an ecclesiastical college developed at Clynnog Fawr. The Glynllifon estate can trace its foundation historically to the 8th century and there is evidence of occupation on the site going back to the Iron Age.

There were a number of quarries in the valley, the largest being the Dorothea and Pen yr Orsedd quarries. Although the major quarries are worked out, there remains demand for slate waste for garden decoration.

In 1991 Antur Nantlle Cyf was established as a community enterprise to work for the benefit of the Nantlle Valley and its surrounding area.

Dyffryn Nantlle was one of the major slate quarrying regions of Wales during the nineteenth and twentieth centuries, having at least 37 operating slate quarries at one given time. It was an innovative region in the development of the slate industry. The Cilgwyn quarry on the north side of the valley is the oldest in Wales and one of the oldest in Europe, dating from the 12th century. The first steam engine to be used in the slate industry was a pump installed at the Hafodlas quarry in the valley in 1807. Slate roofing tiles have been excavated at Segontium Roman camp in Caernarfon and are thought to have originated in the Natlle Valley. The quarries of the area are being considered as a World Heritage site.

Unlike most of the other slate producing regions in Wales the Nantlle Valley developed a large number of small, independent quarries because most of the land in the valley was owned by a number of small landowners rather than a single large landowner. At the height of the industry there were over 50 quarries being worked in the valley. Because of this the quarries were never managed as a large single concern as they were in the Penrhyn, Dinorwic and Ffestiniog quarries and this led to the industry in the area being much more vulnerable to any downturns in the economy. This also led to the development of an industrial landscape that is quite different from the other slate quarrying regions in that there are a large number of small waste slate heaps around the valley.

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Wikipedia