In a low lying area, all these names can refer to far more smaller features than they would in hillier places. The "ridge" in question may have been only twenty foot tall for example, and smaller than a railway foundation.

Some of these may have been artificial and built by native peoples. Others might be remnants of ancient tsunami and hurricanes, changing sea levels, floods and so on.

The same phenomenon occurs elsewhere. The Netherlands have tiny features they call hills. In East Anglia, the flattest region of England, there are tiny hills. If you look at any pictures of the Gog Magog Hills south of Cambridge, you could walk up them barely breaking a sweat. In fact in some of the pictures, you'd struggle to spot the hills. In Scotland, they wouldn't even be considered a hill range.