I haven't proven all this but I think your Elizabeth was a FULL sister to my Mary. Wheee! Please answer at
Descendants of Jacob Ammon

1 Jacob Ammon 1742 - 1819 b: Abt. 1742 in Paradise Twp, York Cty, PA d: Bet. 1819 - 1820 in Fallowfield Twp, Washington Cty, PA
.. +Maria Barbara Lieib 1743 - 1779 b: July 15, 1743 in York Cty, PA m: Bef. 1763 in York Cty, PA d: April 06, 1779
....... 2 Adam Ammon
....... 2 Conrad Ammon 1775 - b: Bef. 1775 d: in Fallowfield, Washington Cty, PA in 1820
........... +Fanny Unknown 1775 - 1820 b: Bef. 1775 d: Aft. 1820
....... 2 Isaac Ammon
....... 2 Jacob Ammon
....... 2 Rebecca Ammon
....... 2 Richard Ammon
....... 2 George Ammon 1765 - b: 1765 in West Manchester, York Cty, PA d: in Franklin Twp, Westmoreland Cty, PA
........... +Esther Markle m: 1786 in Westmoreland (now York) Cty, PA
....... 2 Henry Ammon 1767 - 1771 b: 1767 in W. Manchester, York Cty, PA d: Bef. 1771
....... 2 John Jonas Ammon 1769 - b: 1769 in W. Manchester, York Cty, PA d: in perhaps Rush Cty, IN after 1833
....... 2 Henry Ammon 1771 - b: 1771 in West Manchester, York Cty, PA
*2nd Wife of Jacob Ammon:
.. +Nancy Unknown m: Aft. April 1779
....... 2 Elizabeth Ammon 1785 - 1860 b: 1785 in prob. Washington Cty, PA d: Aft. 1860 in Carroll Cty, Washington Cty, PA
........... +George Grant 1785 - b: 1785 in Basking Ridge Plantation, Liberty Corner, Somerset Cty, NJ m: Abt. 1804 in prob. Washington Cty, PA
....... 2 Mary Ammon 1786 - 1864 b: July 01, 1786 in prob. Washington Cty, PA d: October 13, 1864 in Keokuk Cty, IA
........... +Thomas Legg 1784 - 1847 b: February 27, 1784 in Washington Cty, PA m: Abt. 1804 in Washington Cty, PA d: October 27, 1847 in Raleigh, Rush Cty, IN