Promontory fort - coastal, Doogort, Co. Mayo
Co. Mayo |
Forts
On the northern shore of Achill Island, at the very tip of a low triangular headland above a place locally known as Porteen Cove, an ancient earthwork sits with sheer cliffs falling away on three sides.
It does not appear on any Ordnance Survey map, and the rough, waterlogged grassland surrounding it offers little to draw the casual walker. Yet the headland is a promontory fort, a type of enclosure in which builders exploited dramatic coastal topography to do much of the defensive work for them, throwing up earthen banks and ditches only across the landward neck where the cliff line offered no natural barrier.
The antiquarian Thomas Johnson Westropp noted the site in 1914, naming it after the nearby cove. What he found, and what surveyors have since documented in greater detail, is a headland measuring roughly 27 metres east to west and 12 metres north to south, defended by two curving banks with corresponding ditches cut between them. The inner bank, round-topped and steep-sided, stands about 1.2 metres above its ditch and sits slightly higher than the interior of the fort itself. A shallow, flat-bottomed ditch runs along its outer edge, waterlogged at the eastern end. Further out, a broader but lower earthen bank, about 5 metres wide at its widest, contains large boulders within its fabric, though without any evidence of formal stone facing, known as revetting. A narrow breach in this outer bank, roughly 1.4 metres wide, aligns with a slight rise in the base of the inner ditch, and both features together suggest the ghost of a causewayed entrance, a gap left in the earthwork and bridged across the ditch, which was the standard way of managing access in structures of this kind. The outermost ditch is barely a depression now, read mainly through a band of darker, wetter vegetation.
The interior of the fort is featureless, damp, and slopes gently eastward. Later field walls and fencing have disturbed the edges of both outer ditches, blurring the original lines somewhat. The panoramic view northward across open Atlantic water gives some sense of why the headland was chosen; the site commands everything approaching by sea, while the gently rising ground to the south would have made landward observation equally straightforward.