+———James GERVIN (1811/2 County Tyrone, Ireland – 27 Nov 1875 Ottawa, Ontario, Canada)
          |
      +———Joseph GERVIN (abt 1862 Ottawa, Ontario, Canada – 1953)
      |   |        
      |   |   +———William WHITEHEAD (abt 1797 Kent, England – 8 Aug 1844 Ottawa, Ontario, Canada)
      |   |   |
      |   +———Elizabeth WHITEHEAD (17 Mar 1824 St. Marylebone, Middlesex, England – 15 Mar 1911 Ottawa, Ontario, Canada)
      |       |    
      |       +———Mary Jane PARKER (abt 1805 Waterford, Ireland – 6 Jun 1888 Ottawa, Ontario, Canada)
      |
  +———James Douglas “Douglas” GERVIN (1894 Quebec, Canada – )
  |   |    
  |   +———Elizabeth SMITH (1868 Buckingham, Quebec, Canada – 1946)
  |    
  Walter GERVIN (abt 1917 Ontario, Canada – )
  |        
  |   +———George DAVIDSON
  |   |
  +———Edna Verna DAVIDSON (1896 Quebec, Canada – )
      |    
      +———Mary Ann MILFORD