Three low wall footings, some barely visible above the sod, are all that remains above surface of what may have been the medieval church of St Mochulla. One of them runs flush with the present ground level along the northern edge of the graveyard. Another, just over a metre long, projects from the base of the enclosing wall at what might be its north-east corner, tapering very slightly from base to top in what is known as a base batter. A third, nearly ten metres in length, may represent the east wall of the medieval building, though it has been disturbed by modern repairs and resists easy dating. What is peculiar about the site is the way subsequent generations have, quite literally, built on top of it: the family tombs of the Moloneys and the O'Connells of Kilgorey appear to stand on the very foundations of the older church.

The antiquarian T.J. Westropp recorded this layering of the dead in 1911, noting that Alfred Molony had heard from his father that part of their family vault incorporated foundations of an earlier church wall, and that the O'Connell vault partly covered another. Westropp's diagram of the site shows the medieval church defined on three sides by the graveyard wall to the north, the two family tombs to the east, and an early eighteenth-century church to the south. He measured a stretch of the northern graveyard wall at approximately sixteen metres and labelled it simply 'old church wall'. By the 1921 edition of the Ordnance Survey six-inch map, a rectangular outline at the site is named 'St Mochulla's Ch. (in ruins)', though it does not appear on earlier map editions at all. Excavations carried out in 2005 and 2009 recovered moulded sandstone fragments of a Romanesque door surround from the rubble, pointing to a building of some architectural ambition. Romanesque ornamental stonework of this kind, typical of the twelfth century, suggests considerable resources and patronage. These fragments have since been gathered and are kept toward the eastern side of a graveyard extension.

The hill also carries an older and more elusive tradition. An earlier belief held that the shrine, or even the actual grave, of St Mochulla was located at the very crest of Tulla Hill, which would place it near the chancel of the medieval church. That spot is now occupied by the Moloney family vault. The saint himself gave his name to the village, Tulla deriving from the Irish word for hillock, and the ecclesiastical enclosure within which all of this sits has its own separate identity as an ancient site. The wall footings, the displaced stonework, the family tombs built over older foundations: the whole hilltop is a kind of compressed stratigraphy, each layer pressing down on what came before.