The bullaun stone (above) at Rathduff Church, near Ballina, is known as the Carrowmore Stone, and was in Carrowmore townland until some years ago, when it was moved to its present position for safe keeping. It is said that this stone was used as a mass rock during the Penal times in Ireland, 1691-1760.
Bullaun stones are usually, but not always, associated with ecclesiastical sites, but their function is unknown. The word "bullaun" means bowl or hollow and there may be a single, or several hollows on a stone; the example pictured above has two hollows. The fact that they are often associated with church sites may indicate that they had a religious significance, or they may have just been used for the grinding of dyes or foodstuffs; some suggest that they may have been used for more sinister puposes - human sacrifice.
The rainwater that accumulates in the hollows is often said to have curative powers for warts etc..
The stones are not unique to Ireland and may be found in other countries throughout Europe, and some think, that they may date back as far as the Bronze Age, and that they were "christianised" by the early church.