Ogof Ffynnon Ddu

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Ogof Ffynnon Ddu
Location Upper Swansea Valley
Coordinates 51°49′27″N 3°39′40″W / 51.8243°N 3.6611°W / 51.8243; -3.6611Coordinates: 51°49′27″N 3°39′40″W / 51.8243°N 3.6611°W / 51.8243; -3.6611
Depth 308 metres (1,010 ft)[1]
Length 50 kilometres (31 mi)[1]
Discovery South Wales Caving Club 1946
Geology Limestone
Entrances 3
Access Ogof Ffynnon Ddu Management Committee - see South Wales Caving Club website for details
Translation Cave of the Black Spring (Welsh)
Cave survey [1]
Part of the interior with a terraced cascade and three standing and climbing cave explorers wearing safety equipment

Ogof Ffynnon Ddu (Welsh for Cave of the Black Spring; also known as OFD) is a cave under a hillside in the area surrounding Penwyllt in the Upper Swansea Valley in South Wales. At 308 metres (1,010 ft) deep and 50 kilometres (31 mi) long, it is the deepest cave in the UK and the second longest in Wales.

OFD was discovered in 1946 through digging by Peter Harvey and Ian Nixon, members of the newly formed South Wales Caving Club.[2] Major extensions were discovered in 1967. The system is famous for its intricate maze-like structure and its impressive main stream passage. It forms the Ogof Ffynnon Ddu National Nature Reserve.

One of the largest cave systems in Britain, the caves and tunnels of Ogof Ffynnon Ddu weave a long and tortuous path beneath the Tawe Valley. Deep underground, an assortment of specialised wildlife has developed including cave shrimps and the pale blanched trout endemic to pure underground fresh watercources with sufficient plankton. Deep cracks in the vast expanse of stony moorland above provide habitats to plant life, including the lily of the valley and wood anemone.


  1. ^ a b Gulden, Bob. "Worlds Longest Caves". he NSS Geo2 Long & Deep Caves Web Site. National Speleological Society. Retrieved 28 January 2014. 
  2. ^ Cave discovery anniversary marked BBC Wales - 16 September 2007

External links[edit]