That repurposing, noted by the antiquarian Thomas Johnson Westropp in 1915, tells you something about the complicated afterlives of early medieval monuments in Ireland, and also about the particular mixture of reverence and practicality with which later inhabitants tended to treat them.

The structure is a cashel, the term used for a ringfort, which is a roughly circular enclosure dating from the early medieval period, built from stone rather than earthen banks. At Fanta Glebe, the cashel is nearly circular, measuring about 27.5 metres north to south and 26 metres east to west internally. Its double-faced drystone wall, between 3.5 and 4 metres wide, has been largely rebuilt at some point, and the stones, while well-set, are not especially large, though the basal courses use bigger blocks, reaching up to 1.3 metres in length at the north-west. A gap of about 2.3 metres at the south-east may represent the original entrance, though too little of the wall survives between east and south-west to be certain. A second gap at the north-west is clearly a later alteration. Inside, mature deciduous trees have taken root, and a concrete chicken coop from some more recent era sits in the north-west quadrant, a quietly absurd detail in an enclosure that was already ancient when the deanery was built. A later drystone wall, roughly 11 metres long, runs north to south from the inner wall-face, visible to the east of the cashel. A pathway surrounded by its own drystone wall once connected the cashel to the Deanery building, which stands about 12 metres to the west. The cashel also sits within a large multiperiod field system and has near neighbours: two further cashels lie within 175 metres to the north-north-east and north-east, and a mound sits roughly 172 metres to the west-north-west, suggesting this was once a notably busy corner of the Clare landscape.