This paper discusses deposits laid down in tidal areas in which the range of tide is great. The sediments of the Jade near the mouth of the Weser in Germany are taken as an example. They consist mainly of soft mud, but in places contain admixtures of sand. As a general rule, mud is deposited near highwater mark, silty or sandy mud in areas of intermediate water, and fine sand near the position of the water at low tide. In some places the sediments are laminated and cross-bedded. This lamination is not destroyed by burrowing and bottom organisms that live in great profusion on these tidal flats, probably owing to the fact that the sediments are deposited so rapidly that the organisms do not have time to rework them before they are buried by additional deposits. In some pla es as much as 3 meters of sediment are deposited in a year. The material laid down by tidal waters along the north coast of Germany has the economic advantage of adding arable land to the coast, of increasing the fertility of the soil, and of serving as a therapeutic agent in the form of mud baths.