There are a few such 'walls' dotted along the island's north-west coast. I'm not sure what their function was/is, but wonder if they're anything to do with the second World War, as I know North Hill was used as bombing practise for Normandy for a time until a cow was killed and they decided it could easily have been a person! Bomb craters are also plentiful at this end of the island. I took photos, but forgot which square they were in!
Uploaded to Geograph by Becky Williamson on 5 October 2009
Photo © Becky Williamson, 5 October 2009. Licensed for reuse under this Creative Commons licence