Recent marine sediments.
Marine plain. This is a plain aggraded by waves, tides or submarine current and aggraded by deposition and solution from sea water. This area has then been elevated above sea level.
On the low plains and supratidal flats adjoining the coast.
The surface soils are generally black to very dark grey clays or clay loams which are very high in organic matter in the immediate surface. At about 30 cm, strongly mottled brown brownish yellow and grey clays or sandy clays generally occur. These sediments often contain shell fragments.