A cashel is a type of early medieval stone enclosure, typically circular, built to protect a farmstead or small settlement. The depression at its centre is thought to possibly represent a souterrain, an underground passage or chamber constructed during the early medieval period, often used for storage, refuge, or concealment. It is a quietly uncertain feature, a sag in the earth that raises more questions than it answers.

The identification comes from an archaeological survey of the Ballinrobe district compiled by D. Lavelle and published in 1994, covering the landscapes around Lough Mask and Lough Carra. The site sits within the broader cashel recorded as MA100-044, and the possible souterrain occupies its centre. The cautious language of the survey, using "may represent" rather than confirming the feature outright, reflects how much remains unknown. Souterrains are frequently discovered only when ground shifts or collapses reveal their presence, and many are identified from surface depressions alone before any excavation confirms them.

The site is noted as inaccessible, so there is little to be gained from attempting a visit with the expectation of close inspection. What makes it worth knowing about is less the feature itself than what it represents: the layered, unexcavated archaeology of the Mayo lakelands, where the ground around Lough Carra quietly holds the traces of early medieval life, much of it still unconfirmed and largely undisturbed.