Within the trees, the ground is scattered with loose stones, irregular stony banks, and what appear to be stones set deliberately on edge in a pattern consistent with kerbing, the outer retaining stones that typically defined the perimeter of a prehistoric cairn. The working interpretation is that this is the remains of a robbed-out cairn, a burial mound that was systematically stripped of its material over centuries, leaving only this faint structural ghost behind.

The hill itself takes its name from an eighteenth-century landowner. Writing in 1802, Walter Tighe recorded that the hill was called Knockmajor after a contemporary proprietor, one Major Purcell, and noted the presence on its summit of a small circular enclosure, situated above what appears to have been a place of burial on the slopes below. That description of a circular enclosure is now thought to reflect an early observer's interpretation of what was, in fact, the heavily disturbed remains of the cairn. A cairn, in this context, is a mound of stones raised over a burial, common across prehistoric Ireland and often built on elevated ground to make them conspicuous in the landscape. By Tighe's time, enough material had likely already been removed that the outline of the mound could easily be mistaken for a deliberate enclosure rather than a funerary monument in the process of disappearing.