The fascinating facade of the chapel dates from the 12th century. The lintel is carved with two mermaids: one with a snake's tail and one with the tail of a fish. These might represent temptation or the souls who have died on land and at sea. The arch above is carved with vines spewed from the mouths of large human heads and containing birds pecking at grapes. This is thought to symbolize Creation and Redemption, but the Parable of the Mustard Seed has also been suggested.