Not ruined, not overgrown, simply gone from the surface of the land entirely. What was once marked on the first Ordnance Survey map of 1836 as eight very small forts has since disappeared from ground level, leaving behind only a cartographic ghost and a probable prehistory.

The confusion over terminology is itself revealing. The original surveyors labelled the features as forts, which in nineteenth-century Irish mapping convention was often applied loosely to any circular earthwork, regardless of its actual purpose. By the time the revised edition of the OS map appeared in 1876, the designation had changed to "Site of", a quiet acknowledgement that something had already been lost. Current interpretation suggests these were most likely a barrow cemetery, a grouping of burial mounds of the kind used across Ireland and Britain during the Bronze Age to inter the dead beneath low earthen or stone heaps. Eight such mounds clustered together on a drumlin, one of those smooth glacially deposited hills that define so much of the Cavan landscape, would have been a significant funerary monument. Whether they were levelled by agriculture, eroded over centuries, or simply were never very prominent to begin with, nothing now registers at ground level.

What remains is a question mark on a hillside. The site at Cornasaus is not a place visitors can read easily from the ground; its significance exists almost entirely in the archive of early maps, where the careful notation of eight small circles once indicated that someone, at some point in the distant past, thought this particular slope worth returning to, again and again, to bury their dead.