L:181
V:40

Twll Clogfaen, Boulder Hole


NGR: SO 02254 08476
261 m.asl

Merthyr Tydfil , Northern Outcrop - East (Morlais to Abergavenny)
 map using leaflet map:
Active Pothole
Access See caving.wales for current Access arrangements
Description Climbs lead to stream and shafts to low streamway, tributary streamway to from an aven, and a sump
History Tony Donovan, Roy Morgan, et al., 2014
Hydrology Water said to have been traced to Ogof Pont-y-Meirw by Tony Donovan Tests
Conservation
Gallery

Brendan Marris
2015
Martin Laverty
2026
Grated entrance above Nant Sych
Survey
Dylan Wase et al.,2026
References
Cambrian Caving Council Newsletter 42, July 2014
Brendan Marris Caves of South Wales
Search for further records Browse registry map Browse 3D map
Cambrian Cave Registry entry 2014-1
 Comment? Email registrar@cambriancavingcouncil.org.uk © Caving Wales ⓗ Ogofa Cymru