Sorry, I had meant to clear this one up way back but, as Red Mystic knows, I had a wee accident in August and the stream has only just come back to the surface.
The marriage of the first Donald Beaton that has not been found took place at Nunton in Benbecula 14.8.1873. The wife Maggie of the 1891 Census was Margaret MacMillan, my first cousin twice removed from 12 Torlum, Benbecula, daughter of Neil [mac Aonghais 'ic Dhomhnaill 'ic Chaluim] MacMillan and Catherine MacPherson, daughter of Donald MacPhersonn, the maor or ground officer of Iochdar at Kilaulay Farm but from a Benbecula family, originally of the MacMhuirich bardic line. There are descendants still in Benbecula.
The other Donald Beaton was also from a Skye family, his father John, a shepherd, being noted in Alexander Carmichael's Gaelic collection, Carmina Gadelica, as having a great knowledge of medicinal herbs and flowers as he was descended from the doctors employed by the MacDonalds of Sleat. There is quite a story to this family but I imagine it is the first one that is of interest.
I do have greater detail, especially about the first family above, if you wish to email me directly.
Angus Macmillan