South Wales Caves

Ogof Tarddiad Rhymney Description

Ogof Tarddiad Rhymney (Rhymni) is located in the Cwar Yr Ystrad Quarries about two miles from the village of Trefil (map). The area around the quarries is prone to car crime so it is better to park nearer the village and walk up to the cave. The cave is near the base of the quarry face near an unquarried mass of rock in the larger of the quarries and is generally left blocked up with a dry stone wall. A 2m drop from the entrance gives access to a large fossil passage that carries a small trickle of a stream, this passage varies between 4 and 8 metres wide. This passage continues for about 200m before a junction is met. To the right is a slope upwards to Nant Criban, while down to the left the main passage can be followed for about 300m to a boulder choke. Once through the 10m choke a large passage is regained that lasts for only about 50m before is rapidly reduces in size to a flat out crawl in a sediment filled stream. This can be followed for over 200m before becoming too tight. Nant Criban begins as a small crawl past some straw formations before entering a small chamber. A hole in the floor allows you to drop into the Nant Llwyd streamway, this can be followed for a short distance upstream, while downstream it makes only a visible connection with the main passage. This cave is notable for the fact that it consists of some very large fossil passages that suddenly reduce in size to small crawls at its end. The entrance should be walled up again following a trip.