A sand bar is a narrow ridge of sand or shingle that seals off the mouth of a bay. A spit can grow in size until it completely seals off a bay. A lagoon is a small lake that is formed behind the sand bar. It was originally part of the bay, but it has now been sealed off by the bar.
Lagoon Bar
Processes at work: z„ z„ z„
Deposition
Longshore drift Wind
Marram grass
Longshore drift
Examples include Loch Muiri, Co. Clare, and Lady’s Island Lake, Co. Wexford.
Tombolo
A tombolo is a narrow ridge of sand or shingle that joins an offshore island to the mainland.
A spit can grow in length until it reaches a nearby island. The spit is then known as a tombolo.
An example can be found near Roundstone, on the Galway coastline. Iorras Beag Peninsula and tombolo, near Roundstone, Co. Galway Tombolo Former island
