NSW Marriage 3196/1867 SPARK JAMES L - WARD ELIZABETH - WELLINGROVE
The Sydney Morning Herald - Saturday 12 January 1867 p.1
MARRIAGES
On the 2nd instant, at the residence of the bride's parent, by the Rev. J. H. Johnson, B.A., at Glen Innes, JAMES LYON SPARKE, eldest son of Alexander Sparke, of Sydney, to ELIZABETH WARD, daughter of Mrs. PEPPERCORN, of Glen Innes.
NSW Death 1241/1925 SPARK ELIZABETH (-WARD) 8O YRS MOSMAN
That seems to indicate that Elizabeth's maiden name was WARD. It would then seem that her mother had remarried by 1867 but I can't find a PEPPERCORN + WARD marriage.