La Motte is a tidal island, and listed archaeological site, also known as Green Island, located in the Vingtaine de Samarès in the parish of St Clement on the south-east coast of Jersey, Channel Islands.
There is evidence of human visits to the island since Neolithic times, having left a cairn, a number of middens and cists which were uncovered in the early 20th century. The island rises to 17 metres above mean sea level and can only be accessed at low tide. The rock is from the late Pleistocene covered with loess below a grassy surface.
Wikipedia https://en.wikipedia.org/wiki/La_Motte,_Jersey
Coordinates 49°9'38.455" N -2°4'38.501" E
