Neither Guthrie Smith nor Buchanan of Auchmar identify him as a chief (hence why John Buchanan is the last recognised chief); however, Buchanan of Auchmar advises that John Buchanan transferred "his estate to an old comrade of his, Major George Grant, Governor of Dumbarton Castle, with this provision, that the Major should marry his eldest daughter, and assume the name and arms of Buchanan; reserving his own life-rent and his lady's jointure, and settling the estate so as to return to Buchanan's heirs-male, and, failing heirs of Grant's own body, to Buchanan's heirs whatsoever ." Despite George Grant never marrying the daughter of John Buchanan, National Archives of Scotland (NAS) records show the legal paperwork for this transfer occurred on 9 Apr 1679. NAS records show that by late 1679, George Grant had assumed the name George Buchanan and that by 28 Aug 1680 he was cited as being Major George Buchanan of that Ilk. (The use of the title, Buchanan of that Ilk, implies that George had taken over the chiefship but it might also imply that John Buchanan was deceased by 28 Aug 1680.) Major George Buchanan never married and by his death had "given up all Buchanan evidences, both the rights and the fortune."