They meander, cluster, and thicken in ways that suggest generations of farmers working the same ground at different times, for different reasons, with different tools. A field survey carried out in 1997 identified at least three distinct phases of walling here: broad, old meandering walls up to three metres wide and less than a metre high; a later set, still possibly pre-Famine, built somewhat narrower; and modern strip walls overlying the lot. The oldest of these phases was invisible to the Ordnance Survey cartographers who mapped the area in both 1842 and 1915, which gives some sense of how long they had been quietly collapsing back into the limestone.

The valley sits between Gleninagh Mountain and Cappanawalla Hill on the karst edge of the Burren, and the field boundaries extend not only across the valley floor but up onto the exposed limestone to the west and north. At the centre of the picture, in terms of both geography and archaeology, is a cashel, a type of early medieval stone-walled enclosure, which the field systems predate, postdate, and in some cases may be exactly contemporary with. Particularly dense concentrations of walls gather along the cashel's western side and around several post-medieval houses roughly 180 metres to its north-east. Some of the older walls fit the profile of what researchers have termed tumble walls, a form associated with later medieval agricultural activity. Evidence from a pollen core taken from Poulacapple bog, around four kilometres to the south, adds a broader ecological context: it points to increasingly intensive arable farming in the area from around 1000 AD, continuing until a shift to wetter conditions sometime before 1650 AD. The valley is not unique within Rathborney in this regard; two other field systems of comparable complexity and potential age lie in its north-east corner and along its eastern side, each associated with its own enclosures or ringforts. The working assumption is that all of these systems were once connected, forming a single agricultural landscape across the valley floor, before field clearance and reorganisation, documented between the two editions of the Ordnance Survey maps, erased most of the evidence that would have linked them.