During archaeological monitoring of that project, a small but telling deposit emerged from the ground: a compact oval scatter of fire-cracked sandstone and charcoal-rich silt, sitting quietly within a shallow hollow cut into white and yellow glacial marl.

The site was excavated under licence no. 00E0204 by archaeologist Paul Stevens in 2000. What he uncovered was a fulacht fiadh, or burnt mound, one of the most frequently encountered prehistoric monument types in Ireland. A fulacht fiadh is essentially the debris left behind by an ancient cooking or heating method, in which stones were repeatedly heated in fire and then dropped into a water-filled trough to bring it to the boil; the cracked, shattered stones were then discarded in a mound nearby. The deposit at Rossbrien measured 4.2 metres in length, 1.8 metres wide, and just 0.15 metres at its deepest, making it a modest example. Excavation revealed no definitive cut into the underlying material, and the hollow itself had an irregular profile, suggesting the site had not been heavily engineered. No other archaeological features were found in the surrounding area. Stevens noted, however, that the marshy flood-plain terrain is entirely characteristic of where fulachta fiadh tend to be found; proximity to water and low-lying ground appear to have been deliberate choices by the people who used such sites.

The site at Rossbrien no longer exists in any visible form; it was identified and recorded as part of a monitoring process tied to infrastructure development, meaning the ground has long since been disturbed or built over. Its interest lies not in what a visitor might see today but in what its discovery tells us about the landscape beneath modern Limerick. The glacial marl in which the deposit sat is a reminder that this flood-plain terrain was shaped by ice-age processes long before any human activity took place here. For those curious about the methodology behind such finds, the excavation report is summarised on www.excavations.ie, and Stevens's account appears in the 2002 volume of the relevant site records.