I have a Joseph Edwards and a Mary ? as great-great-grandparents but perhaps not enough information to confirm that they are the people you're seeking.
Some of the facts are:
Joseph born abt 1805; died abt 1870
Mary ?? born abt 1810; died May 3, 1877 (this from an entry in the Caylor-Edwards family bible)
Children: Laura Virginia Edwards and James William Edwards (not certain if there are other children)
The family lived in Loudoun County for a number of generations and were located in or near Edwards Ferry. I don't have any records of Mary's maiden name but am researching documents in Loudoun County to gather information on the Edwards side of the family.
The discrepancy is in the dates - if Mary was really born in 1810, then she can't be the mother of your Jane Edwards (b. 1815). However, my birth dates are uncertain.
If you have information to confirm or deny any of this material, I'd appreciate hearing either way.
Regards,
Bob Stoy