The structure in question is a togher, an ancient trackway laid across boggy terrain, and this particular example is about as minimal as such a road can get. It measures just fifty-five centimetres wide and twenty centimetres deep, and consists of a single ash plank laid lengthways, east to west, resting on transverse rods of hazel roundwood beneath it. Two timbers, one purpose, one direction.

Toghers range considerably in their construction, from elaborate multi-layered platforms of split oak to simpler arrangements like this one, which archaeologists classify as a class 3 togher, indicating a relatively modest method of assembly. The hazel rods running crossways beneath the ash plank would have held it above the worst of the waterlogged ground, distributing weight and preventing the surface timber from pressing straight down into the peat. Hazel and ash were both common and practical choices in early Irish woodworking, readily coppiced and worked without great effort. The bog itself is responsible for preserving the structure; the acidic, low-oxygen conditions that make wetlands so difficult to cross also happen to be extraordinarily good at keeping organic material intact across centuries, sometimes millennia. Without the bog, the plank and the rods beneath it would have rotted away long ago, leaving no trace at all that anyone had ever tried to cross this stretch of ground.