One of the Scottish Megaraks, George Currie, mentioned this stone to me. It's not marked on the OS Landranger map, but it's most definitely there. 200 m or so in from the road, just off a rough track. About 1.7 m tall, and 0.7 m wide, it stands proud with a terrific viewpoint north, west and south, just on the SW shoulder of Drumderg. It's obviously a great favourite with the sheep, too, as the eroded area round the base and traces of wool on the shaft show. From one angle it looks a bit like an upright axe-head.