Originally designed to lie flat over graves as recumbent markers, most of them were lifted upright at some point during the eighteenth or nineteenth centuries and pressed into service as ordinary headstones. The recycling was practical enough, but it came at a cost: standing vertically, a significant portion of each slab disappears below ground level, and carved details that were meant to face upward now face sideways or are hidden entirely in the soil.

The majority of the slabs are cut from schist, the dark flaky metamorphic rock common to this part of Wicklow, though four of the twenty, including the one known as Cross Slab 12, are of granite. That particular slab stands roughly ten metres south of the west doorway of Aghowle Church, itself a medieval structure of some age. The granite is 9cm thick and currently rises 44cm above the ground, tapering slightly from 50cm wide at the base to 42cm at the top. Carved into its east face is an outline Latin cross 33cm across, formed by a shallow groove just 2cm wide and 8mm deep. The upper arm of the cross has suffered some damage where the stone has shattered at the top, and the lower transom extends below the present ground surface, its full extent unknown. The cross-slab as a form is among the earliest types of Christian grave marker found in Ireland, predating the more familiar free-standing ringed high crosses, and examples like these at Aghowle offer a direct, unadorned record of early Christian burial practice.

Because the slabs are clustered where eighteenth and nineteenth century headstones are densest, they can easily be mistaken for ordinary grave markers of that period. Looking closely at the faces of the stones, particularly at ground level, is the only way to pick out the carved grooves from the general weathering of the surface.