An intertidal sandflat, mudflat, and marsh area developed in some lagoons in mesotidal areas, and in protected bays and estuarine areas along macrotidal coasts. Extensive tidal flats occur in the Wash (eastern England), Wadden Zee (Holland), and along the North-Sea German coast. Tidal flats also occur in warmer climates, as in the Persian Gulf, where carbonate and evaporite deposits develop. In tropical areas tidal flats tend to be colonized by mangrove swamps.