A spread of burnt and fire-cracked stone once lay to the east of a small stream, but by 1981 the site had been levelled, leaving behind little more than a scatter of discoloured earth as evidence that something was once cooked, or heated, or processed here across a very long stretch of prehistoric time.

The site belongs to a class of monument known as a fulacht fia, the most common prehistoric archaeological feature found across Ireland. The term refers to a type of ancient cooking or heating site, typically consisting of a horseshoe-shaped mound of burnt and shattered stone built up beside a water source over repeated use. The standard interpretation is that a trough, dug into the ground nearby and filled with water, would be heated by dropping fire-cracked stones into it. The stones, unable to withstand repeated thermal shock, would eventually fracture and be discarded into a growing mound. Why the one at Farranastig sat in rough grazing beside its particular stream, who returned to it, and over how many generations, is not recorded. What is known is that the physical trace of all that activity was gone by 1981, recorded only in passing in a county inventory compiled some years later by Walsh.