Somewhere beneath the bogland of Rossan townland in County Longford, there may lie the continuation of an ancient wooden trackway, its precise location marked on record not because anyone found it there, but because the geometry of what was found elsewhere pointed in this direction.

Toghers are bog roads, constructed from timber to allow movement across wet, unstable ground. They range from rough arrangements of brushwood to carefully engineered structures of split planks and supporting timbers, and they can date from the Bronze Age through to the early medieval period and beyond. The Rossan togher enters the record sideways, so to speak, through its neighbour. During turf-cutting in 1995 and 1996 in Chancery townland, County Westmeath, a section of togher was exposed at a single location. It was roughly two metres wide, built from transverse planks laid across a pair of longitudinal runners, and it ran on a north-south orientation. That alignment, projected forward, would carry the structure across the county boundary and into Rossan. The Irish Archaeological Wetlands Unit noted as much, suggesting it was highly likely the trackway extended in that direction. The Longford entry exists entirely on that inference. No timber has been uncovered on the Rossan side; the location is, as the record itself acknowledges, purely conjectural.

What gives this a quiet fascination is what it illustrates about how wetland archaeology works. Bogs preserve organic material extraordinarily well, which means ancient wood survives where it would rot away in drier ground. But the same bogs that protect these structures also conceal them completely until a turf-cutter's machine happens to pass over the right spot. A road that may be centuries old remains invisible a metre beneath the surface, its existence inferred from a bearing and a reasonable assumption about where a path was going.