It measures roughly 14 metres from north to south and 9 metres from east to west, unremarkable in silhouette but carrying a very particular kind of prehistoric signature. This is a fulacht fia, a type of site found in enormous numbers across Ireland, formed by the repeated use of heated stones to boil water, most likely for cooking. The stones, cracked by thermal shock, were raked out and discarded in a crescent-shaped mound around a wooden trough, which is why these sites survive at all: as slow accumulations of spent, shattered rock.

The mound at Coolbane appears to correspond with a site recorded in 1934 by a researcher named Bowman, who noted a fulacht fiadh on land then belonging to a H. Bresnahan. The reference, published in 1934 at page 635 of the relevant record, is brief, but it places the site within a tradition of early antiquarian observation in the region. What gives the location an additional layer of interest is proximity: a second fulacht fia lies approximately 140 metres to the south-west. Whether the two were contemporary and used in relation to each other, or separated by generations of activity, is unknown, but their closeness is not unusual. Fulachtaí fia often cluster near watercourses and low-lying ground, and north Cork has a substantial concentration of them. Bronze Age in date for the most part, though some sites span other periods, they represent one of the most common yet least visually dramatic forms of prehistoric monument in the Irish landscape.