Copied from a well known book:
CWM PWLL-Y-RHYD YSTRADFELLTE
NGR 9114 1375 A 948 feet
L948 feet
About 200 yards south of the Pont Cwm Pwll-y-Rhyd. A large chasm running across the river bed which takes the Afon Nedd Fechan in flood. At the bottom is a large pool with a 90 foot long sump which connects with White Lady Cave qv. To the left is a lofty passage with some formations in the roof. A climb up leads to an exit high above the river and a crawl at floor level leads to a lower exit.
First recorded visit by R?nnfeldt 1890 surveyed by SWCC in 1959. In 1987 work by SWCC, Croydon CC and Unit 2 CR&E produced 984 feet of new passage.
See page 5 for survey.