It has been labelled on maps as a causeway, annotated as a ford, and described as sand and shingle, and the ambiguity is the point. Despite the confident naming, there is no visible evidence of any deliberately built structure here. What appears to cross the water is simply a natural bar of gravel and sand, roughly 120 metres from east to west and between 50 and 80 metres wide, that has quietly served as a route across the lake for as long as people have needed to reach the island.

The feature appears on both the 1838 and 1930 Ordnance Survey six-inch maps, depicted as stony ground with a track or road running across it, shown by parallel dashed lines continuing from a mainland road out to the island's eastern shoreline. The 25-inch Ordnance Survey plan labels the crossing as "Causeway" and annotates the surface as "Sand & Shingle"; the 1930 six-inch map calls the same crossing a "Ford". The two maps also show the track taking slightly different routes across the bar, which suggests that the usable path shifted over time, as one might expect from a natural feature subject to seasonal water levels and sediment movement. The place was never, it seems, engineered so much as opportunistically used, the landscape offering just enough dry ground to make a crossing possible.