To a passing eye it might read as a natural undulation in the land, the kind of gentle swelling that Kerry fields produce in abundance. In fact it is a fulacht fia, one of the most common yet least understood monument types in the Irish archaeological record. These burnt mound sites, found in their thousands across Ireland, are generally dated to the Bronze Age and are thought to represent places where water was repeatedly heated, most likely by dropping fire-cracked stones into a trough or pit. The shattered, heat-reddened stone accumulates over time into exactly the kind of horseshoe or oval mound visible here.

The mound at Coolatoosane measures 9.45 metres northeast to southwest and 13.75 metres northwest to southeast, dimensions that place it comfortably within the typical range for sites of this type. A well originally stood close by, which is significant. Fulachtaí fia are almost invariably found near a reliable water source, since the entire process depended on a ready supply. That well has since been fully covered over, erasing what would have been a key part of the site's original character. The measurements and the note about the well come from C. Toal's North Kerry Archaeological Survey, published in 1995, which documented the monument as part of a systematic effort to record the archaeology of this part of the county.