Henrhyd Falls
Geology
The falls occur where the small river, the Nant Llech (grid reference SN854122) drops over the faulted edge of a hard sandstone known as the Farewell Rock which forms the top half of the rock face and which forms the base of the South Wales Coal Measures. Beneath this, and forming much of the recessed portion of the drop, is the Subcrenatum Sandstone separated from the Farewell Rock above by the Subcrenatum marine band. Both the marine band and sandstone are part of the Bishopston Mudstone Formation included within the Marros Group, the modern name in South Wales for the assemblage of strata that was traditionally known as the Millstone Grit series. A stream gully between the descent path and the falls marks the line of the Henrhyd Fault which is responsible for the falls' presence.
One of the area's most famous visitors was Sir William Edmond Logan (later head of the Geological Survey of Canada). In 1833 he carried out detailed geological survey work in the area, discovering a mile (1.5 km) down the valley from the foot of the falls the fossil trees which now stand in the garden at Swansea Museum. They are 'Object 1' in their 'History of Swansea in 20 Objects'.
Access
The waterfall is reached after a steep walk down into the valley from the car park established by the National Trust, and is a popular spot to visit. A further footpath leads steeply down to the falls via the opposite side of the valley, accessed from Dol Henrhyd, the road that goes to Coelbren village.