Rosemary,

As far as I know, Caroline/Carrie Wiliams, Joshua Wililams' sister, married a Henry Sampson. They married in Cumberland County in January 1854. I have a copy of their marriage record. I have no idea of Henry's parentage, but was told that he was white.

Now if Sophia was a Sampson by blood, then that means that her daughter Caroline/Carrie Williams, possibly also married a cousin, Henry Sampson. I don't have much else to go on, and I haven't searched the Robeson County records because I wasn't sure of any connection.