Promontory fort - coastal, Tearmann Caithreach, Co. Mayo
Co. Mayo |
Forts
On the low-lying western shore of the Mullet Peninsula in County Mayo, a headland of roughly 24 hectares is defended by a single curved wall, and almost nothing about it is immediately obvious.
The wall, which runs 170 metres across the neck of the promontory, has long since collapsed and been swallowed by grass. Sea-thrown rocks litter the interior, old cultivation ridges corrugate the ground, and sheep graze where people once lived. The scale of the place is what stops you: the interior stretches approximately 600 metres in length and up to 400 metres across at its widest point, making it less a fort in any conventional sense and more a fortified landscape.
A promontory fort of this type works on a straightforward but effective principle, using a naturally defended headland and closing off the landward approach with a wall or earthwork. Here, that wall was originally around 1.7 metres wide and survives to about 1.6 metres in height on its outer face, with faint traces of inner and outer ditches still readable in the terrain. It is best preserved towards its centre and deteriorates towards either end; no original entrance has survived. Named Portnafrankagh by the antiquarian Thomas Johnson Westropp, who described the site in 1912, the fort once contained considerably more than is visible today. Westropp recorded souterrains, those underground stone-lined passages used for storage or refuge, with distinct passages and chambers, as well as huts with enclosing walls and lintelled gateways through the main rampart. What survives now is a quieter picture: four sub-circular hut sites, each three to four metres in diameter, reduced to grassed-over rubble mounds, and two lengths of collapsed souterrain visible only as shallow depressions, their drystone walls intermittently breaking the surface. The cultivation of the interior over subsequent centuries almost certainly accelerated the erosion of these features.
The contrast between Westropp's early twentieth-century account and what Markus Casey documented in his 1999 survey of Irish coastal promontory forts is itself a kind of record, a measure of a century's worth of slow loss. Several earth and stone banks extend eastward from the defensive wall outside the site, though their connection to the fort remains unclear. The sea, as the original builders would have known well, is easily accessible from within the interior.
