I am researching some names which must be connected somehow.
William ALLARDYCE who married Mary MORRISON (b 1780ish) in Bourtie, Aberdeenshire 21 July 1799. When above Mary Morrison died she had been living with her daughter Findlater ALLARDYCE (b 1813ish) and her husband Robert HAY in Slap, Turriff. Another daughter Mary ALLARDYCE (b 1808ish in Culsalmond) married John GIBB and they lived together in Insch. Your Mary ALLARDYCE must be a grandson to William and Mary, either through an unknown brother or as an illegitimate child of Findlater or Mary. Have you had any luck tracking down her parents' names?
I'm pretty certain we're connected but not quite sure how.