|--------
                      |
           |---------William MCMACHEN (1690, Scotland - 1749, Virginia)
           |          |
           |          |--------
           |
  |------John MCMACHEN (1723, Ireland - 1789, Tennessee)
  |        |
  |        |          |--------
  |        |          |
  |        |---------Elizabeth BLAIR?(BROOKS?) (1700, Great Britain - )
  |                   |
  |                   |--------
  |
Isabelle Jean MCMAHON (1765, Virginia - 1829, Indiana)
  |
  |                   |--------
  |                   |
  |        |---------
  |        |          |
  |        |          |--------
  |        |
  |------Isabella BARNES (1730 - )
           |
           |          |--------
           |          |
           |---------
                      |
                      |--------
Sources for this individual:  @S229@ ; History of Washington County Tennessee, 1988; worldconnect data of Margaret Simpson, db margaret2