Unfortunately, time and the restricted winter ferry timetable meant this one had to be dropped from my recent trip. Infuriating when you're standing at the bottom of the track and another half hour would have done it.
It's a Clyde long cairn (53m long) which, from all accounts, although overgrown, still has three chambers with capstones visible.
On the western shore of the isle, near Scarrel Point*, exists a cave designated "The Piper's Cave," which the natives believed to be the opening to a subterranean passage through Eenan Hill to Carnbaan or Achavulig (Ach-a-bhuilg), where its exit was. Supernatural beings inhabited this dark retreat, which no mortal dared enter. A bold piper essayed this forlorn-hope, and was heard by his friends gaily piping underground until his slogan became hushed in the depths of the mountain. As he passed under the hearthstone of Lenihall farmhouse, he was heard lamenting that he had not a sword-hand as well as two for his pipes, and he would have routed the ogres and demons attacking him ("Da lamh air son a Phiob agus lamh air son a chlaideamh."). Then the music ceased - forever.
*Is this near Michael's Grave? Quote from 'The Isle of Bute in the olden time" by J K Hewison, 1893.