That the garden sits slightly higher than the surrounding land is not a trick of perception or a quirk of drainage; it is the accumulated evidence of an earthwork that was old enough to be mapped by the Ordnance Survey in 1914 and may be considerably older than that.

The enclosure is roughly 14 metres across, defined by an earthen bank that survives in better condition on its southern and western sides, where it reaches about 80 centimetres in height on the outer face and 50 centimetres on the inner. To the north and east, the bank has been levelled almost entirely, leaving only a faint swell in the ground. A more recent ditch cuts across from east to south to west, a reminder that agricultural land does not stay still. Circular earthen enclosures of this kind are common features of the Irish countryside and served a range of purposes, from enclosed farmsteads to cattle pens. The scale and form of this one, relatively compact and without the complexity of an elaborate entrance or internal structures recorded above ground, lends weight to the suggestion that it may have functioned as an animal pen, a simple enclosure for keeping livestock secure. Whatever its original purpose, it was substantial enough to leave a mark on the landscape that persisted into the twentieth century and beyond, even as the earth was gradually turned over for cabbages and carrots.