Not sure if this person has been identified, but I just ran across a
cemetery survey for a "Portis" cemetery in Surry Co, NC. (And I know
there were Poythresses in this neck of the woods.)
The only identifiable marker listed is for an "Anna Reed," wife of
Allen Portis, (b. 9-1-1792, d. 6-3-1848).
See the survey here: