The structure is orientated northwest to southeast, and though its date is unknown, the technique involved is one of the oldest forms of managed fishing: stone flags driven vertically into the riverbed to create low walls, arranged in an arc designed to funnel fish rather than simply block their path.

The two arms are built from scattered flagstones and slatey siltstone, and together they form a curved enclosure with a gap of roughly ten metres at the point of deepest water flow. That gap is significant. A fishtrap of this kind typically relied on a removable basket or net, woven from wicker, placed at the narrowest point where fish would be forced to pass. No wooden stakes survive here, which distinguishes it from other intertidal fish weir types that used timber frameworks as their primary structure. The stones are now in a state of collapse, and the site appears to have been adapted at some point, perhaps from around the eighteenth century onwards, to serve as a kelp grid, a low stone platform used to dry and process harvested seaweed for the local industry that was once economically important along this stretch of the Cork coast.

The structure sits in an intertidal zone, meaning it is only visible at low water. The townland is Lackaghane, in the Baltimore area, and the crossing channel between the mainland and Illaunacullin is the rough frame of reference for anyone trying to locate it. What remains is fragmentary, but the two arcing lines of stone, still legible in their basic geometry, suggest something purposeful and long-used rather than accidental, a piece of infrastructure that the estuary has been quietly reclaiming for longer than anyone has thought to record.