This from Stanhope White
“Not far from the Percy Rigg village, on Ayton Moor at NZ598114, is a square enclosure with rounded corners; the earthen wall have been almost eroded away, but it can be seen that there had been an internal ditch. This cannot have been a defensive work, and a similar structure in a far better state of preservation exists at Studfold Ring. The name implies an enclosure for horses and the internal ditch can be seen today in many open air zoos.”
The North York Moors.
1979