Heather: Allan Mcgibbon and Ann Mack had no children as a couple however Ann Mack did have a child Robert Mack. Roberts father was George Tannahill and they were not married. Geo. Tannahill left for California and his twin brother Hugh was the witness to Roberts baptism several years after his birth. After Robert was grown, Ann Mack married Allan McGibbon.
I am a descendant of Robert born 1851 or 1852, depending on what record you read.
Robert and his wife Mary Elizabeth Hamilton had six children;
Andrew Pollock Mack, born 1874, Huntingdon; John Wilbert Mack, my Grandfather, born May 3, 1876, Godmanchester, Huntingdon, Que., George Allan Mack,b. Aug 1878; Annie Mack b. June 1872; William Walter Mack b. June 1874; Thomas Herbert Mack b. Oct. 6, 1889. All the family except Andrew P. Mack moved to Sask around 1906-1910.
I can provide more detail in a private message if you wish.
James Wilbert Mack