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.

[3][4] 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 that now stand in the garden at Swansea Museum.

[6] 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 to Coelbren village.