It measures roughly four metres across and barely half a metre high, but that modest profile is typical of one of the most common prehistoric monument types in Ireland, and one of the least understood.

The mound is what archaeologists call a fulacht fia, a term used to describe the crescent-shaped or oval spreads of burnt stone and charcoal that survive in their thousands across the Irish landscape, most frequently in wet or low-lying ground. The waterlogged setting at Pallas is characteristic; these sites are almost always found near streams, springs, or boggy hollows. The prevailing theory, developed largely through experimental archaeology in the latter half of the twentieth century, is that fulachta fiadh were used for cooking, with water heated rapidly by dropping fire-heated stones into a trough until it boiled. The spent, shattered stones were then raked aside, accumulating over repeated use into the mounds visible today. Some researchers have proposed alternative functions, including textile processing or bathing, and the debate has not fully settled. What is consistent is the Bronze Age date that most of these sites carry, placing activity at Pallas somewhere in a broad window between roughly 1500 and 500 BC, though individual sites can fall earlier or later.

The Pallas example is small, with its roughly oval spread of burnt material measuring 3.2 metres north to south and four metres east to west, but its survival in marshy ground is itself part of the story. Waterlogged conditions tend to preserve organic material and suppress the disturbance that draining and cultivation bring, which is one reason so many fulachta fiadh have endured in exactly this kind of marginal, soggy terrain.