Logwood forests fringe all the lagoons and many parts of the seaboard, which are flooded during the rainy season.
On each side of the town are lagoons.
In process of time some of these banks, as in the case of Venice, raised themselves above the level of the water and became the true shore-line, while behind them lay large surfaces of water, called lagoons, formed partly by the fresh water brought down by the rivers, partly by the salt-water tide which found its way in by the channels of the river mouths.
But it was inevitable that, when the barbarians, Lombard or Frank, were once established on the mainland of Italy, Venice should be brought first into trading and then into political relations with their near neighbours, who as masters of Italy also put forward a claim to sovereignty in the lagoons.
South of this point the coast curves outwards and is broken by peninsulas and indentations; to the north it is concave and bordered in many places by dunes and lagoons.