When I was researching the Louisa County records, it appeared to me that there were both white and mixed-race members of the Bunch family in the county. However, after reading Mark Bunch's/ Ancestry.com's article more carefully, I think he is right. All members of the Bunch family of Louisa County descended from one of the first African American slaves who had a child by a white woman. (The family may have taken their name from the slave named John Punch or from a woman named Bunch who had a child by a slave).
This is extraordinary since it means that two of the great, great granchildren of the slave, brothers of the president's ancestor Samuel Bunch, were part of the upper class. Both James and William Bunch were called "Mr." in the colonial period. William used a silk handkerchief in 1740. James wrote as well as the court clerk.
Some of their neighbors must have known of their ancestry because they had lived next to them for generations. And the Louisa County court indicted Samuel Bunch for failing to list his wife as a tithable.
Paul