Tombolos are complex features that develop when longshore drift a joins an island onto either the mainland or larger island. Dorset take various forms. The 28-km shingle of Beach in the former of onto has grown south-eastwards to join the Isle Purbeck the mainland and in the process has cut off a large area of sea to form lagoon; this is Britain's largest tombolo. Perhaps the most s tacular tombolo in Europe is the one that gave its name to all others the Tombolo di Orbetello in Tuscany, Italy. In this case there are two sand s (one trendin the the mainland and joined the former Monte Argentario island onto have created a large lagoon within which the town of Orbetello isLocated on causeway. The Lagoon was the of Italy'fleet of flying boats during the Fascist era of the 1930s and 1940s have formed where cuspate forelands tink up with islands. There are many examples of this along the coast of Australia where old patches of coral reef have been attached to the mainland. In the Isles of Scilly off Cormall, there are several examples of these smaller tombolos, including that which links Toll's Island to St Mary’s