Geograph - photograph every grid square

See Link (at WoSAS) for the archaeological details; such archaeological reports described the remains as those of a causeway or, more specifically, of a "Roman causeway", and this interpretation found its way onto maps.

The author of this shared description disagrees, believing the visible remains to be merely those of a lateral jetty (indeed, the first-edition OS map of c.1858 clearly marks a jetty here), with the sheltering and current-slowing effects of the nearby Lang Dyke (a long training wall; see Link for details) making the remains better-preserved than they would otherwise have been. See NS4273 : Supposed remains of a Roman causeway for a longer account of the reasoning involved.

The fact that some of the land between the lateral jetties on the Clyde is known to have become silted up and grassed over (to the benefit of some land-owners) may account for the apparent continuation of this "causeway" for some distance inland from the shore; other nearby known jetties show similar continuations. It is worth adding that, in the time since I first questioned the nature of these remains, some maps that marked the site as an old causeway have stopped doing so.

The original reports of this site as a former causeway attempted to link it with remains of roads on both sides of the River Clyde. The archaeological reports (made in the 1970s) about the roads themselves are also problematic, for various reasons that are unrelated to the "causeway"; see Link (in a Geograph article), where the subject is discussed at some length.