Maybe this isn't the right spot - I'm assuming it is because it's high ground near Shiskine, and a fort is the right kind of place for fairies to hang out being antisocial.
Once upon a time a bevy of faeries met on the summit of Durra-na-each, near Shiskin, and proceeded to amuse themselves by throwing down pebbles amongst the trees of the Mauchrie forest. The "rules of the game" required that the stones should be thrown from between the finger and thumb. Many centuries have passed since then, and the giant oaks of the Mauchrie have crumbled into dust, but over the moor may still be seen the pebbles of the faeries in the gray monoliths and stone circles which lie buried in the moss and heath.
p40 of 'The Antiquities of Arran' by John McArthur (1861).