Gelli Hill stone

After stepping through the fence next to the circle we walked rather blindly into the fog with no more than my memory to go on, it was adequate, we went straight to it, first it was my imagination , then it was a sheep, Eric said its a tractor, it wasn’t, it was the fallen stone. It looks like a big door wedge or block of cheese, with lots of smaller stones about it.
If it was standing it wouldnt be much more than a couple of feet tall, but from the circle it might have been edge on and a perfect horizon marker.