Or it may not. That ambiguity is part of what makes this spot quietly remarkable. The upright timber piles recorded in 1869 by the antiquarian Harkness could be the structural remnants of a prehistoric walkway, or they could be the stumps of a Bronze Age forest that was swallowed by rising lake water long before anyone thought to write anything down.

Lough Gur has been absorbing and releasing its secrets in roughly equal measure for over a century and a half. When the lake was artificially drained in the mid-nineteenth century, the exposed bed around Garret Island yielded stone axes, bone pins, animal bone, and a small quantity of human bone, all recorded by Harkness in 1869. The Ordnance Survey six-inch map of 1840 shows a circular island with its surface just one metre above lake level; by 1897, with the water 1.5 metres lower again, the same island appeared dramatically larger on the twenty-five-inch edition, stretching 170 metres north to south. Excavations carried out by Liversage and Mitchell in 1958 confirmed that lake levels were lower still in prehistory, and that the present foreshore was once a forest, its stumps now preserved in silt and lakewater. Séamus Pádraig Ó Ríordáin, writing in 1954, noted a dugout canoe lying on the lake bed between the island and the peninsula, and made passing reference to timber piles near the Knockadoon shore, adding another layer of ambiguity to what Harkness had described eighty years earlier.

Garret Island sits 150 metres north-west of the Knockadoon peninsula, where decades of archaeological excavation have uncovered Neolithic and Bronze Age monuments of considerable significance. The island itself has evidence of prehistoric settlement, though access to the water's edge rather than the island is what concerns most visitors to this feature. The submerged reefs to the south are not always visible; conditions in late June, when water levels tend to drop and sunlight falls at a useful angle, offer the best chance of seeing the geological fissures in the rock beneath the surface. By late September, even in a dry year, the reefs can disappear entirely from view. Looking from the Knockadoon shore towards the island on a calm summer morning, with the right light, the shallow water does at least allow you to understand why people once moved across it rather than around it.