No exposed stonework, no dramatic collapse, just a depression in the earth that points to something beneath: a souterrain, an underground passage or chamber typically built during the early medieval period in Ireland, often used for storage, refuge, or both.

The enclosure with which this souterrain is associated is a separate recorded site in its own right, and the relationship between the two is characteristic of the early medieval Irish landscape, where enclosed farmsteads, known as raths or ringforts, frequently concealed subterranean structures beneath or just inside their banks. Souterrains were generally constructed from dry-stone walling and roofed with large lintels, then buried under the ground surface. Their entrances were deliberately narrow, making them defensible and discreet. The depression visible at Newtown is the kind of telltale sign that results from the gradual settling or partial collapse of such a roof over centuries, leaving the ground above it slightly sunken.