This piece of rock art literally fell out of the gap in the wall behind it in 2008, having been placed with the carved face inwards when the wall was being built. Several such pieces have been discovered this way in the Carlow area over the past couple of decades.
The walls here are very substantial, piled four feet high or more and almost as thick. They cross the hillsides for miles around. Who knows how many more pieces are hidden within them.