Erosion is all around us, from the meandering course of rivers and other waterways, to the gradual carving out of channels in even the toughest mountains, and the softening of features in statues.

Incipient foredunes are sometimes ephemeral features, tending to be eroded ... or saucer-shaped depressions or hollows formed by wind erosion of a pre-existing sandy substrate or dune (Figures ...