When you walk along next to a stone wall you sometimes notice places where the wall is tumbled over. Trees occasionally fall on a wall and other events like passing animals or mild earthquakes can reveal a weakness in the wall. When this happens, the tumbled off rocks are next to the wall and the wall is lower and has a break or gap in it at the point where the tumble occurs. So I was walking along next a wall paying slight attention and came to this:
Closer:Here we have a sort of tumble of rocks next to the wall but the height of the wall remains constant in the stretch passing the tumble. This suggests it is not a "tumble" but rather a more deliberate addition to the structure. It is about 7 feet long, and I don't have to tell you what would fit under there.