History and Geology
The attraction of Waterfall Country lies in its spectacular mix of raw natural beauty and the legacies of man's attempts to make a living from this landscape.
Waterfall Country falls within the Fforest Fawr Geopark.
Each one of the growing international family of Geoparks is an area with an important and often extraordinary geological heritage. Geoparks are not just about rocks, however, they are also about people. Fascinating human stories emerge from their unique landscapes. Geoparks celebrate local legends and culture, archaeology and our wider relationship with the land. They are also firstclass outdoor classrooms and places for scientific study. Fforest Fawr Geopark became a member of the European Geoparks Network and the UNESCO Global Network in 2005.
During successive ice ages in the last couple of million years the Vale of Neath has been gouged out by glacial ice so that its floor is hundreds of metres lower than it would have been prior to the ice ages. This has resulted in the various tributary rivers of the Neath (Mellte, Hepste, Nedd Fechan etc) being rejuvenated - cutting down into their beds to form the deep gorges characteristic of Waterfall Country. Downcutting has been most effective where the bedrock is mudstone whilst sandstone beds offer more resistance and are responsible for the falls and rapids. Where much older faults have brought the two rock types into conjunction, downcutting by rivers in the mudstone has normally left a projecting lip of sandstone which in the most extreme cases is tens of metres high.
With continued fracturing of the underlying exposed mudstones and their removal, the stresses on the protruding sandstone cap-rock above leads to its collapse. Severe weather conditions – high flow rates and severe frosts can be expected to accelerate the process. By this process the waterfalls migrate slowly upstream at a rate which can be determined by the distance between the current location of each individual fall and the fault which often lies some metres downstream of it. Sgwd yr Eira provides a good example of this process, one which continues to this day, as evidenced by the problems experienced with loose rock in 2008.
There are around 130 known historic sites within Waterfall Country, ranging from the hillfort at Craig y Ddinas, the industrial buildings of the Glynneath Gunpowder Works to Sarn Helen - an ancient Roman road running between Coelbren and Brecon Gaer forts - that skirts the north-western edge of Waterfall Country.
The industrial remains of the area are relatively rich; the southern fringe of the Park is geologically varied and it is this and the topography of the area that allows for a variety of historic sites and remains. Extractive industries included two silica mines and associated features, limestone burning and millstone quarrying. Those that used the rivers as power sources were the corn mill and the Gunpowder Works. The latter is thought to be unique in Wales. Nineteen remnant post-mediaeval buildings are for the most part listed included in Brycheiniog XVI, and are of some architectural interest.
The industrial sites were located close to their source of material or power. The lime kilns, probably producing for local agricultural use, were located on areas of enclosed limestone; silica was mined where found and the corn-mills and Gunpowder Works were situated to take advantage of the water power provided by the rivers, and in the case of the latter the enclosed and isolated location was a safety consideration.
The distribution of sites leaves no doubt that many sites still await discovery and/or recording. Some of these may be major, comparable to the large scale quarrying complex on Moel Penderyn, which includes features such as quarries, inclines and tramways. The majority of the unrecorded sites however may be small, but that is not to say unimportant.