In Tavraun townland, County Mayo, local tradition held that a mass rock once stood, one of the flat outdoor altars used by Catholic priests to celebrate Mass in secret during the Penal era, when public Catholic worship was suppressed under British law. The tradition was strong enough that the site was formally recorded in the Record of Monuments and Places in 1997, entered on the basis of a local source. When a field inspection was carried out in November 2016, however, no physical trace of the rock could be found.

This outcome is not entirely unusual for mass rocks. They are often modest, unmarked features, sometimes a naturally flat boulder, sometimes a slab propped at one end, easily mistaken for ordinary field stone or removed entirely over the intervening centuries. What distinguishes Tavraun is that the tradition itself was considered credible enough to warrant formal listing, yet the landscape has since yielded nothing to confirm it. The gap between the memory and the ground is, in its own way, part of the record. Oral tradition carried the site forward through time; the land did not.