Black Keld Catchment

The two cave systems (Langcliffe Pot and Mossdale Caverns) include over 20 km of cave passages. These cave systems are unique in the way parts of the drainage is constrained within Yoredale limestones and then passes through to underlying Great Scar Limestone.^[3] These cave systems pass through the intervening shales and sandstones that in other places form an impermeable layer. Such breaches of these impermeable rocks are due to streams forming routes through tectonic fissures, faults and fractures. The breakthrough from the Middle Limestone into the Simonstone Limestone occurs via a canyon within a vadose zone.^[1]

Langcliffe Pot and Mossdale Caverns have complex reticulate cave passages that are unusual for sites in Yoredale Limestones which more typically have a single stream passage.^[4]

54°07′36″N 1°59′16″W / 54.126755°N 1.9877235°W / 54.126755; -1.9877235