Another name for Mary was Mary McTavish.
From Find A Grave (Oliver Lasby):
Mary married Oliver Lasby, son of Charles Lasby and Margaret Challenor. (Oliver Lasby was born on 27 Dec 1808 in Milwich, Staffordshire, England, died on 8 Jan 1860 in Acton, Esquesing Twp (Halton), Canada West (Ontario), (Canada) and was buried in Acton Pioneer Cemetery, Acton, Halton, Ontario, Canada 3.)
1 http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi, http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=:1777150&id=I100030762.
2 www.findagrave.com, Oliver Lasby Find A Grave Memorial# 142244951.