When Mr P. P. Griffiths of Pen-y-wyrlod Farm, Talgarth, Breconshire rang the National Museum of Wales in June 1972 to announce the discovery of human remains in a stony mound on his farm, not previously recorded as an antiquity, I assumed that this must be one of the not uncommon new discoveries of Early Bronze Age round cairns. To my consternation, the following day, I was shown, in a field close to Pen-y-wyrlod (SO 151316) a long cairn far more substantial then any other previously recorded member of the Cotswold-Severn group in the Black Mountains area: it was fully 60 m. long, 25 m. wide at the widest part, and about 3 m. high—but, alas, already severely damaged by the growth of a small quarry which the farmer had been developing, in all innocence, for several years past, as a source of rubble for his yards and gateways. After all, as the farmer pointed out, the site is not recorded as an ancient monument on any map and he had concluded, as the Ordnance Survey must also have done, that it was a natural feature.