They are easy to miss, half-buried and fragmentary, but read correctly they describe a field system that once divided this hilly, limestone-broken ground into a series of sub-rectangular plots, each somewhere between thirty and fifty metres across.

The walls survive immediately to the south of a cashel, the circular stone enclosure, typically early medieval in origin, with which they are associated. A cashel was essentially a fortified farmstead, its thick drystone wall enclosing a domestic space, and the field boundaries around it would have represented the working agricultural ground that sustained whoever lived inside. At Coolnaha, those boundaries were laid out with a practical logic, following the natural undulations of the terrain rather than imposing a rigid geometry on it. That they appear in aerial photography at all is largely because the modern rectilinear fields built around them during land reclamation have, in one case to the west, simply erased them. The field to the south was more fortunate; enough remains visible as low rubble to allow the outline of the older system to be read, at least partially.

What a visitor finds here is understated almost to the point of invisibility. The limestone outcrops that break through the pasture give the landscape a particular texture, and the cashel itself anchors the eye, but the relict walls require patience and a certain willingness to look at the ground rather than the horizon. The southern field, immediately beside the cashel, is where the remnants are best preserved, the stones sitting low against the turf, their arrangement only becoming legible once you understand what you are looking for.