Tanning was the process of converting raw animal hides into leather, a trade that demanded large quantities of water and was typically located close to rivers for that reason. What makes this particular site quietly remarkable is not simply its age but its preservation: the wooden uprights and base-beam of the tanning pits, along with the fills of those pits, which still contained animal hair, survived intact beneath whatever was later built above them.

Archaeological testing carried out under licence reference 04E1697 uncovered the structural evidence, recorded by McLoughlin in 2008. The site sits on an east-facing slope running down toward the Slaney, which flows on a northwest to southeast axis roughly 250 metres to the northeast. Tanning pits were essentially large vats or excavated chambers where hides were soaked in tannin-rich liquids, often derived from oak bark, over a period of months or even years. The presence of animal hair in the pit fills is exactly what you would expect from a working tannery, where scraped and soaked hides would shed material into the surrounding deposits. That such organic evidence survived at all is a function of the particular conditions of the soil and the fact that nothing above ground disturbed what lay below.