Farewell-rock definitions

A series of sandstones which lie at the boundary of the Coal Measures with the underlying Marros Group in South Wales.

Origin of farewell-rock

Said to have been coined by ironstone miners who once worked the siderite deposits which stratigraphically overlie this rock unit. Digging beyond this bed would yield no further iron ore and so, on reaching it, they could bid a farewell to further riches.