The significance of Cnoc Sgeir na h-Uidhe (aka Callanish XIV) is hypothesised in the book The Stones Around Callanish (ISBN: 0 903960 67 2) by the Pontings:
...the chief interest of this site is that the small erect stone is east of the circle at Callanish I. Thus for an observer at the main site, sunrise occurs directly above site XIV at the equinox.