Dan-yr-Ogof, DYO, Under the Cave, Dan yr Ogof Resurgence, Darren-yr-Ogof, Cliff of the Cave, Tarren yr Ogof, Llan-yr-ogof, Cave church, Dan-yr-rogof, Llenvah Spring

NGR: SN 83820 16000
225 m.asl

Powys , Northern Outcrop - West (Black Mountain)
map using leaflet map:
Rising Cave
Access The first part of the cave is a show cave and can easily be reach from the Sennybridge-Swansea road. The cave is owned by the Dan-yr-Ogof Cave Co. Ltd and the cave is managed for access by cavers by the Dan-yr-Ogof Cave Advisory Committee. Only parties accompanied by a Warden (Leader) appointed by DYOCAC may go beyond the show cave Current Access arrangements
Description First recorded exploration by the Morgan brothers in 1912, The river cave can be followed for 120 metres to a sump. The show cave is 520 metres long and leads to a series of four lakes beyond which is a complex series of passages and chambers ending in a long crawl. In 1966 a major extension to the cave was discovered some one mile in length. Two further extensions were subsequently discovered giving the cave a length of over 9 miles. The old cave and first part of the new extensions run in a SW direction, the known passages then running north.
History Marked on Kitchin's 'accurate map of Brecknockshire' (~1770) as Llenvah Spring; Dan-yr-rogof on Greenwood's map(1828). First explored by the Morgan Brothers 1912. Extended by The Dragon Group in 1939, SWCC, CDG 1964
Hydrology 35oz. fluorscein appeared in 50 hrs from Sinc y Giedd (Harvey, 1948). In very wet conditions, fluorescein from Waen Fignen Felin to DYO in 8 hrs (Hunt, 1963). Spore tests from Twyn Tal-Ddraenen, Carreg Lem, and Lost Valley Sink.
SSSI: 0854 Mynydd Du (Mixed) NNR: Dan-yr-Ogof GCR: 557


Brendan Marris
Old cave. G.Platten. 1938. Plan only. Private
Old cave, J.H.Davies. C.R.G. grade 4. 1952 Plan only. Private
Old cave based on various surveys with new additions, A.Coase C.R.G. Grade 4, Plan only. Limited publication
Provisional survey of 1966 series. D.Thomas C.R.G. Grade 1 and Plan only. Published privately
Show cave survey. N.S. Christopher 1967. C.R.G. Grade 6c Plan and section. unpublished
Wessex CC Jnl 109, 1967, p.141
Composite survey of all known cave. Plan only based on above surveys, A.Coase and D.Judson. Published. SWCC
BCRA Transactions, 1977
DYO Survey Data
Jones, Theophilus, A History of the County of Brecknock, v2, p.658 (1809) "On the north of the Tawe a little below the fall of the Tawyne is a rock called Daren yr ogof, or the rock of the cave, from this springs up at once a sufficient quantity of water for turning a grist mill at all seasons of the year; this brook, or rather river, called Llynfell, from Llyn a liquid and ell a common termination: after crossing the turnpike road from Brecon or Trecastle to Swansea: soon falls into the Tawe, the inhabitants observe that in a rainy day this river does not perceptibly increase, but that on the following day it becomes muddy, and the quantity of water is considerably greater; there is nothing singular in this, the rain falling on the mountain above has not only a very considerable depth but many varieties of soil to penetrate before it reaches the hollow of this cavern, and consequently a long portion of time is required before the additional water can swell the common current..."
Pembrokeshire Herald and General Advertiser, 25 August, 1848, British Association for the Advancement of Science meeting, Swansea, excursion: Caves and waterfalls of Llan-yr-Ogof, in the limestone hill of Cribbarth
Cambrian Travellers Guide, Nicholson, G., 3ed,p.4591813;;1840, "On the N. of the Tawe a little below the fall of the Tawney is Daren-yr-ogof, "the Rock of the Cave;" from this issues a very strong stream, but not equal in quantity to the spring at Ogmore, in Glamorganshire "
A General View of the Agriculture & Domestic Economy of S.Wales (London, 1814), Davies, W., v1.p.110"the peaty colour of the water at this time proved that it had connection with the turbary hollows...to the west"
The Geology of the South Wales Coalfield, Part V, A.Strahan, T.C. Cantrill, 1904, p.20
British Caver, 2, 1937, p.12, 42
Yorkshire Ramblers' Club Journal, Volume 7 Number 23, pp.52-61, Dan-Yr-Ogof and the Welsh Caves and pp.79-88, Cave Exploration
British Caver, 3, 1939, p.97
British Caver, 4, 1939, p.70
Dan-Yr-Ogof Caves, Swansea Valley, Official Guide, pp.29, Llew.E.Morgan, 1939, includes the definitive account of 1912 explorations by the three landowners and their gamekeeper, with photos
British Caver, 5, 1940, p.21
British Caver, 6, 1941, p.50
British Caver, 6, 1941, p.57
British Caver, 11, 1943, p.57
CRG nl 15, (1948), P.I.W.Harvey, Notes on water tracings carried out from Pwll Byfre and Sink-y-Giedd
SWCC, 1949
Cullingford, C.H.D. (1951) Exploring Caves,pp.74-75
SWCC Newsletter, July 1956
British Caver, 28, 1957, p.67
British Caver, 29, 1958, p.84
BGS [borehole] record of spring, 1958
SWCC Newsletter 44, 1963, p.14 [David Hunt in Digging Prospects]
SWCC Newsletter 49, 1965, p.9
SWCC Newsletter 50, 1965, p.23
SWCC Newsletter 52, 1966, p.11
SWCC Newsletter 55, 1967, p.5
SWCC Newsletter 56, 1967, p.23
Wessex CC Jnl 109, 1967, pp.140-143
SWCC Newsletter 59, 1968, p.4
SWCC Newsletter 60, 1968, p.16
SWCC Newsletter 60, 1968, p.21
CS 13(2),p.67, Owen Clarke, Relationships between surface geomorphology and speleogenesis in South Wales [Cretaceous age?]
SWCC Newsletter 63, 1969, p.4
SWCC 64, 1969
SWCC Newsletter 65, 1970, p.1
SWCC Newsletter 67, 1970, p.9
Descent 10, 1970, p.12
Descent 12, 1970, p.3
SWCC Newsletter 69, 1971, p.33
SWCC Newsletter 71, 1972, p.6
SWCC 71, 1972, p.11
CDG nl.24, pp.21-22 (1972), Corbel's Chamber sump; Mazeways Extensions/Mazeways Rising/Bakerloo/Washing Machine
SWCC Newsletter 72, 1973, p.7
SWCC Newsletter 78, 1974, p.1
BCRA Transactions, Volume 4, No's 1 & 2, March 1977
SWCC Newsletter 91, 1979, p.2
Descent 40, 1979, p.40
Descent 53, 1983
Descent 60, 1984, p.6
CDG nl.92 (1989), Dan-yr-Ogof
CDG nl.93 (1989), Dan-yr-Ogof
Descent 92, 1990, p.8
Descent 96, 1990, p.9
SWCC Newsletter 105, 1989, p.35
Limestones and Caves of Wales, 1989, p.190
Red Dragon No. 23, p.11
SWCC Newsletter 106, 1990
Descent 97, 1991, p.7
Descent 100, 1991, p.8
Descent 102, 1991, p.12
SWCC Newsletter 106, 1990, pp.5-7, Bill Gascoine, A Hydrological Study of the Dan-yr-Ogof and Ffrwd Las Resurgences
SWCC Newsletter 106, 1990, pp.7-8, Paul Dolphin, Letter to the Editor [re water chemistry and hydrology suggesting unrecognised flows and passages]
Descent 107, 1992, pp.20-22, Brian Murlis, Pushing Dan yr Ogof [Mazeways; Corbel's Chamber; Battle of Britain]
SWCC Newsletter 110, 1992, p.6
Caves and Caving 56, Summer 1992, p.15
CDG nl.106 (1993), Dan-yr-Ogof
Descent 113, 1993, p.10
Caves and Caving, Summer 1993, p.6, Nig Rogers, Dan yr Ogof: No-Man's-Land, in Bill Gascoine, South Wales News
SWCC Newsletter 112, 1993, p.28
SWCC Newsletter 112, 1993, p.40
SWCC Newsletter 115, 1995, p.34
CDG nl.116 (1995), Dan-yr-Ogof
Caves of South Wales, 1995, p.97
Caves and Caving, Spring 1996, p.6
SWCC Newsletter 118, 1996, p.106, Recalling 1966
SWCC Newsletter 118, 1996, p.161
SWCC Newsletter 118, 1996, p.190
CDG nl.121 (1996), Dan-yr-Ogof
Descent 128, 1996, p.10
CDG nl.125 (1997), Dan-yr-Ogof
Descent 133, 1997, p.10
Descent 135, 1997, p.11
Descent 138, 1997, p.14
Karst and Caves of Great Britain, 1997
Descent 146, p.10, Martyn Farr, Penetrating the void at Dan yr Ogof
Caves and Caving 90, pp.29-34, (2001), Clive Gardener, Dan-yr-Ogof - part 1
Caves and Caving 90, pp.35-37, (2001), Keith Ball, Dan-yr-Ogof - the Geological Framework
Caves and Caving 90, pp.37-39, (2001), Liam Kealy, Dan-yr-Ogof - Exploration since 1991
Caves and Caving 90, p.40, (2001), Tony Donovan, Dan-yr-Ogof - Explorations in the Show Cave
Caves and Caving 90, pp.40-41, (2001), Mike McCombe, Dan-yr-Ogof - Digging from the 1937 Series to the Rising
Caves and Caving 90, pp.42-43, (2001), Joel Corrigan, Dan-yr-Ogof - Plumbing the Depths and Scaling the Heights
Caves and Caving 91, pp.26-28, (2001), Clive Gardener, Dan-yr-Ogof - part 2
CDG nl.140 (2001), Dan-yr-Ogof
Descent 181 p.14 (2005) Wigmore's dig
Descent 202, p.10, Richard Frost, Explorations at Cascade Aven
Descent 204, p.18, Richard Frost, More exciting Dan yr Ogof discoveries [Chamber Pot Series]
Descent 205, p.13, Richard Frost, More Dan yr Ogof finds
Descent 206, p.19, Martyn Farr, Dan yr Ogof exploration
Descent 207, p.13, Martyn Farr, Dan yr Ogof
Descent 208, p.18, Richard Frost, Rottenstone revisited
Peter I.W.Harvey 2009 Early Days in Dan yr Ogof, and the Beginnings of OFD and SWCC
CDG nl.170 (2009), Dan yr Ogof (Resurgence to Battle of Britain Series)
Descent 209, p.16, Richard Frost, Tortuous Windows
Descent 222, p.12, Richard Frost, Due west in Dan yr Ogof
Descent 222, p.12, Martyn Farr, Dan yr Ogof extensions [Battle of Britain & Gwyn Saunders Hall]
Descent 224, p.13, Richard Frost, The high and the mighty
Descent 225, p.14, Richard Frost, Reach for the sky
Brendan Marris Caves of South Wales
BGS Archives: BCRA/201W/B/3-14, 1937-1956
Cambrian Cave Registry entry 287
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