Susan, I am descended from Willis Abbott, b. 1815 in S.C. and d. 1907 in Alabama. I had thought he was the son of John Abbott (William and Mary's son) but learned from someone that John's Willis died in Mississippi. That person (whom I don't remember, possibly was you) suggested that my Willis may have been a son of Matthew, John's brother. Do you have anything on Matthew's line?
Also, do you have anything on David Abbott, b. 1802 in S.C, died after 1880 in Georgia? He was married to a Margaret.