Roughly six metres along its long axis, about 1.3 metres wide and just over a metre high, it presents, when approached from the south, something very close to the profile of an altar table. This is the mass rock, a category of site that speaks directly to the period of the Penal Laws, when Catholic worship was suppressed in Ireland and priests were forced to celebrate Mass outdoors, often in remote or elevated locations where a congregation could gather with some warning of approaching authorities. The outcrop carries no carvings, but erosion has scored its surface with lines that occasionally intersect at right angles, producing natural cross-like patterns. Whether those patterns were noticed and welcomed by the people who used this place is impossible to say, but it is difficult not to register them.

The ridge on which the rock sits runs east to west, dropping in a series of steps from its higher western end. Its southern face is relatively gradual, but the northern side falls away almost vertically in places. That combination of exposure and elevation gives the site unusually wide views across the eastern coastlands of Clare Island, including clear sightlines to several stretches of the Lighthouse Road near Maum and to the lighthouse itself. For a congregation gathering here under difficult or dangerous circumstances, those views would have been practically useful. The flat, grassy area immediately to the south of the outcrop could have accommodated a modest group. The rock's identity as a mass rock was recorded from Michael Joe O'Malley, whose local knowledge preserved the name and the association that might otherwise have gone unregistered.