HLW (Gw) 9

Nantlle Valley  

2001  

Outstanding  

Designated  

This area on the west of the Snowdonian massif is centred on the Nantlle valley, a typical U-shaped, glaciated valley with steeply rising sides above a flat floor about 100m above OD. On either side there are hanging tributary valleys, and the area extends to the watershed summits above these, from Moel Tryfan in the north at 427m above OD to Mynydd Mawr in the east at 698m above OD, and along the line of summits up to 700m above OD in the south east, from Y Garn as far as Garnedd Goch. On the west, the area includes the quarrying settlements of Penygroes and Llanllyfni at the entrance to the valley. The area contains extensive and well-preserved remains associated with the industrial extraction of slate, which, because of the way in which the quarrying was organised, has created a landscape of distinctly different character to those of the other slate areas of Bethesda (Ogwen Valley pp.105–108), Dinorwig (pp. 88–91) and Blaenau Ffestiniog (pp. 77–80). The area also has associations with the early Welsh Mabinogi tales, and in the 1770s provided the inspiration for one of Richard Wilson’s best studies of a Welsh landscape, Snowdon from Llyn Nantlle.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. The most widespread evidence for early occupation is to be found in an extensive range of late prehistoric, relict settlements and fields on the south facing slopes of the valley around Caeronwy to the east of the slate quarrying area. There are four principal areas including a small Iron Age fort, a number of hut group settlements, enclosures and hut circles with their associated field systems covering many hectares. To the west, and continuing under the slate waste tips, is a further area of relict fields, presumably of similar date. Similar remains have recently been noted on aerial photographs on the south side of the valley, and a further group lies at the top of the valley, just above the Drws-y-coed copper mines, whilst the entrance to the valley is guarded by a small Iron Age fort known as Caer Engan, sited on a natural knoll next to the River Llyfni. Little is known however, of the early occupation of the valley floor, although much may have been buried by the later slate workings and tips.There were formerly two lakes in the Nantlle valley, the lower having been drained in 1893–5.The isthmus between the two (bala) is presumed to have been the location of Baladeulyn (or Llynbaladoylen on Saxton’s map of 1578) which was the maerdref and administrative centre of the commote of Uwch Gwyrfai in the medieval period, and also, presumably, the Baladeulyn in the fourth branch of the Mabinogi, to which Gwydion, in his search for Lleu, followed a sow to ‘Nantlleu’ where there was an oak growing between the two lakes. Perhaps the earliest slate quarrying in North Wales took place above the Nantlle valley. It has been suggested that slate found at the Roman fort of Segontium in Caernarfon came from Cilgwyn. The area centred on the village of Talysarn consists almost entirely of a series of pit quarries, the remains of slate winning and working. The scale of working was smaller than in the main slate working regions of Snowdonia to the north east, and surviving features are more widespread, due partly to the fact that several landowners (by contrast to the large estates of Penrhyn and Vaynol) were involved. Many quarry leases were let, and space for working was confined. There were considerable difficulties involved in raising slate from the pits and in keeping them free from water, and the ingenious ways which were found to solve these problems, including blondins, chain inclines and vast revetments, are some of the principal reasons why the slate quarrying remains in this area, many of which are unique, are so important. Some of the principal features include the 1906 Cornish beam-engine at Dorothea, a unique survival in Wales, the mill and a number of pyramids, also unique, and the blondins at Pen-yr-Orsedd. Today only one quarry, Pen-yr-Orsedd, continues in operation, the most successful, Dorothea, having finally closed in 1971. Slate was originally taken out from the valley by cart, initially to Foryd, to be shipped to Caernarfon, and later straight to Caernarfon, but from 1828 the horse-drawn Nantlle tramway went direct to Caernarfon quay.This was also the first public line in North Wales.Although a sub-branch of the London and North Western Railway was laid from Penygroes to Talysarn in 1872, the section from Talysarn to Pen-yr-Orsedd survived until 1963 as the only British Railways horse-drawn line. The smaller scale of many of the enterprises in this district, and perhaps differing land tenure arrangements, produced a distinctive landscape of dispersed crofting settlements on the slopes above the valley, very different in some ways from that around Bethesda in the Ogwen valley. On the southern slopes of Cilgwyn in particular, the tightly-packed remains of very tiny fields with drystone-walls are a remarkable survival, probably representing tenure of land during the preceding 18th century. As the demand for slate reached a peak in the mid-19th century, a spread of new settlements grew up associated with the quarries, with Biblical names such as Carmel (Fron), Cesaraea, Nebo, Nasareth, although some of these fall outside the area described here. For the most part, these settlements were unplanned, usually just rows of houses strung along a road. Although overshadowed physically by the slate quarrying further down the valley and historically by the fame of Parys Mountain in Anglesey (pp.70–72), the remains of Simddedylluan and Drws-y-coed copper mines nevertheless are significant and cover the narrow floor of the valley and spread up its sides at the eastern end of the Nantlle valley.The remains of the Drws-y-coed complex of mining and processing installations, well-documented from the 18th century onwards, although possibly medieval or earlier in origin, includes foundations for crushing machines, the ruins of buildings, a level, a reservoir and a tower directing water to a wheel, the large pit for which remains as does a protecting wall. Nearby are the remains of what are referred to as the 18th century Stamp Mill and Level Stamp. On the slopes to the south are various shafts and levels and small ore-processing shelters. The underground works were extensive, reminiscent of Parys Mountain, and mainly to the south of the road through the valley. Lower down the valley are the remains of the Simddedylluan mining complex. Buildings and other workings near the road have been largely razed, although the rocky escarpment up from the road is riddled with workings, including Garnon’s Shaft with a nearby horse whim circle and capstan base. To the north, and across the narrow valley, are the adits of Benallt mine, an unusual, possibly fraudulent, undertaking of the mid to late 19th century. Down at the slate end of the valley, there are also slight remains of Gwernor copper mine, including an adit, leat and aqueduct, behind Gwernor farmhouse. Out of the valley itself, the slate quarrying remains extend northwards behind Mynydd Cilgwyn and over to Moel Tryfan. In addition to the quarries themselves, including Alexandria and Moel Tryfan, this northern part of the area includes fascinating examples of the crofting settlements mentioned earlier, as well as part of Rhosgadfan, a landscape immortalised in this century by the authoress Kate Roberts in her autobiography Y Lôn Wen, and providing the inspiration for her numerous novels and short stories.