Looking for family ancestry of John Duffy born in 1879 married to Mary Warnock born in 1897. Children were Donald (1933), John (1929), Eileen (1937), Rosemarie (1931), Kevin (1933), Kathleen (1939).
Did you try to find Mary in the 1901 Ireland census ?
http://www.census.nationalarchives.ie
John Duffy is a very common name my advise would be to look for more details about Mary Warnock first