Islands of Ireland: Mesolithic 'kitchen middens'

This column cannot be charged with the crime of inconsistency: last week Brown Island and this week Brown Island.
This one is not much more than a ploughed field with a cliff of boulder clay. It is tethered to the mainland by a causeway that is overwhelmed at spring tide, thus qualifying it for this series. It is a remnant of an area about five times its size that was subsumed into the mainland over time.