It is an arch stone, most likely displaced from the doorway of the medieval church that once stood on the same ground, the original opening long since broken out and gone.

The fragment is all that visibly remains of the architectural ambition of Maddockstown's medieval church. Arch stones of this kind were cut to form the curved head of a doorway, each wedge-shaped piece depending on its neighbours to hold the whole in compression. When such a doorway collapses or is dismantled, the individual stones tend to scatter or be reused, which makes the survival of even one piece worth noting. The church itself, recorded alongside this fragment as a separate monument, has not fared much better than its doorway; what remains at the site is the graveyard, still in use, while the building that once anchored it has effectively dissolved into the landscape. The fragment is therefore doing quiet archival work simply by existing, offering a small material clue to the scale and character of a structure that would otherwise leave almost no readable trace above ground.

The stone can be found within the graveyard itself, towards the north-eastern end of the site. It is the kind of detail that rewards anyone already picking their way among the older grave markers, though it is easy to overlook if you do not know to look for it.