From Datum S near New Bridge in the North to Datum W on Black Ridge in the South. From Datum D close to the Red-a-ven Head to Datum L not far from Knack Mine.
Long ago, they had a letterbox series out for them, we searched for and found them too.
The triangular topped signs are evidently part of the Moor's extensive military history. However we cannot for the life of us remember what they were designed to do. The term 'datum' suggests they are out there for navigational reasons. Possibly for callibrating distance and direction of firing.