This is one of two chambered cairns on a forest walk.
This is the one you come to first - known as Dunan Mor. An easily-missed arrow on a post points the way to the lower Dunan Beag.
Covered in vegetation which is a pity because the round cairn covers an unusual arrangement of three chambers in a Y-shaped layout. The SE chamber is the most visible.
I would think this relates to Dunan Mor (or Dunan Beag) as they are near to North Blairmore. You'd think there would be nearer stones to use.
On the farm of Blairmore, near the base of Dunfiun, may be seen the scattered ruins of a chambered cairn. On the stones being carried away some years ago, to build the Lamlash school-house, a series of inner cells was exposed, each covered with a single flat stone.
p22 in 'The Antiquities of Arran' by John McArthur (1861).