Large quarry pit marked on the 1891 OS, 30m E-W, 20m N-S and approx. 12m deep. Exposed beds are at an inclined angle. A tunnel (NPRN520406) emerges in the SW corner. Quarried at a higher level to NE. It belongs to the earliest phase of working at Bwlch Cwmllan (401443). Modern OS mapping marks the feature as a pond.
Recorded as part of RCAHMW Uplands Initiative Project. W.B. Horton, H&H, 16/9/2011.