I have Balsillies in my tree. There were three sons, Francis Balsillie, William Balsillie and Balfour Balsillie recorded as being born to William Balsillie and Margaret Turner in Perthshire. This information was found in FamilySearch and therefore the usual care must be exercised. The remainder of my information comes from original records.
William Balsillie b 25 January 1798 in Monzie, Perthshire, Married Isabella Darg, 4 May 1828, Dunbar, E. Lothian, Died 3 April 1835, Haddington, E. Lothian
Francis Balsillie b 4 October 1800 in Monzie, Perthshire, Married Charlotte Purves, 21 December 1829, Stenton, E. Lothian, Died 16 June 1840, Ayton, Berwickshire after a fatal fall from a horse.
Balfour Balsillie b 22 September 1805 in Pencaitland, East Lothian, Married Christian Purves, 16 November 1833, Stenton, E. Lothian, Died 1880 in Whitsome, Berwickshire.
Charlotte and Christian Purves were sisters, children of Andrew Purves and Sophia Craise of Stenton, East Lothian.
Sophia Craise was my 3rd great grandaunt, sister of Agnes Craise my 3rd great grandmother.
I have information on the Francis and Balfour descendants but since William Balsillie did not marry into my Craise line his information is more limited although latterly his family moved down to Northumberland.