Checked my disk copy, but among the 8-10 Abigails (+abby) in index found none listed born after 1761. One of latest also had daughter Abigail (not indexed), born 1793, but not a fit. Index thus not always complete, but hard to ferret out single names not listed. Suggest if you haven't, try the US census records for 1850 back to 1790. Possible there might be updating to the book or in private files. Maybe others might help your cause given time on the message board. Good luck.