Some turtles

One I've posted before...well, actually two, but the first video is edited to stop at the turtle because I hadn't noticed it the first time I posted the video.

The turtle in the end of the stone wall in the video above faces down toward a creek. It bears a resemblance to this turtle, which is right next to a swamp. Notice how both turtles are near (but not on) the bottom of the wall?

Then, this turtle is at the top of the wall between the two rooms in the chamber.
Or maybe they are shim rocks. I could see why you might want the two shims on the bottom, but what's that little shim at the top doing to stop that giant slab from rocking? Incidentally, when I took that picture, I wasn't looking at the turtle, I was looking at the small amount of surface area of rock which was holding that giant slab up off my head!