View on a small nature reserve near Vatrop hamlet on the former island Wieringen.It was formed during the second last ice age, 126.000 years ago, and consists mainly of pushed up boulder clay.
The raw march (obsolete: salt marsh) is a type of soil that forms the transition between the watt and the marsh. It is periodically flooded and shows the beginning of soil formation.
Once a tidal area is no longer flooded daily by the tides, the soil development begins. It forms plant growth (swelling), which becomes more intense with the decrease of the flood periods, so that salt marshes form.