Minllyn is a slate and slab quarry (nprn 310049) begun in the C19, the most productive phase of which began after the Carlyle Slate & Slab Company was formed in 1872. Work ceased in 1924. The construction of neatly laid dry-built slate into a large block appears to be later, of no practical function, and to be unconnected with the quarry, except as a source of stone. It measures 1.3m x 0.9m and 1.2m high.
Recorded as part of RCAHMW Uplands Initiative Project, W B Horton, H&H, 14/12/2012.