The peat has not destroyed what lies beneath so much as preserved it, and beneath the surface of what Mitchell called the Imlagh Basin, a 4km by 2km depression running from Foilnanean in the west to Shrone Point in the north, there are walls, hut remnants, trackways, and field boundaries that have simply been sealed in place by the accumulating bog.

Mitchell identified up to fifteen separate stretches of walling running across the basin and along its cliff-edge rim, from Beenaniller Head to Culloo Head. They vary considerably in construction: some are double lines of upright slabs, others single rows of large stones laid transversely, and at least one, Wall 10, is a ditch and bank rather than stonework at all. The most substantial is Wall 13, which runs for at least 750 metres and, where peat samples were taken from beneath it, returned a radiocarbon date of 2680 plus or minus 90 BP, placing its construction roughly in the Iron Age. Near its north-western end stand the remains of a circular hut just 3 metres across internally. Wall 12, a complex of interconnected walls that meets Wall 13 at one point, appears to have formed a series of irregular fields covering around 1.25 hectares. Radiocarbon dates from this complex suggest it was built and used across a long period, somewhere between 2900 and 2050 BP. Within it are the remains of four probable huts and a small enclosure, and to the north-east of Wall 15 is a large circular enclosure 30 metres in internal diameter, with hut foundations built into its western and south-eastern sides.

The field system does not exist in isolation. The Imlagh Basin also contains six fulachta fiadh, the burnt mounds associated with prehistoric cooking or industrial activity, along with early ecclesiastical sites, a standing stone, a stone platform, and both earthen and stone trackways that were laid directly into the peat. The narrow rim of peat-free ground between the cliff edge and the basin's northern and western limits still shows stretches of walling that have not yet been fully buried, giving a rare glimpse of a farmed and inhabited coastal landscape that was gradually overtaken, rather than violently abandoned.