I'm replying to my own post with hope that this may help someone else.

While searching "Descendants of Gregory Bonnifield (1726-1794)" on ancestry.com, I found that Mattie May Bonnifield b 1874 was the daughter of Samuel Jackson Bonifield b 1843 and "Biddy Tidwilliger" b abt 1852.

I found Samuel Jackson Bonnifield and his wife Isabel (assuming Biddy is short for Isabel) in the 1870 Masaac Co Ill census. I then found Isabella with two Bonnifield children Charles M Bonnifield and Mattie E (should have been M) Bonnifield in the 1880 Mississippi Co MO census. Isabel had remarried to an Anderson at this point as Samuel Jackson Bonnifield died abt 1879. I still have not found anything else on "Biddy Tidwilliger" who shows up as Isabel and Isabella on the census.

I think that "Tidwilliger" is likely a transcription error. By exhaustively searching the 1860 Masaac Co Ill census, I found a family with the last name of "Teremiliger", but there were no children named Biddy, Isabel, or Isabella.

Does anyone know anything else on Isabella (Biddy) Tidwilliger?

Thanks,
-Dennis