Sorry to take so long, Pam. I did not visit the Black forum until now and do not remember getting a notice of your post.
Your Black family in Barnwell, South Carolina does not seem to be related to my Abbeville Blacks who settled there prior to the Revolutionary War. How interesting to have a Maine to South Carolina migration. Have you tried to find a birth record online for F.O. Black? Maine has some early records that I've used. Good hunting.