Most black people descended from slaves will have non-African surnames. Slaves were not allowed to keep their own names, family connections, native languages, or religious beliefs after landing on these shores.
This percentage is growing at a remarkable rate, however. So quickly that a major national magazine (was it TIME magazine?) predicted that in something like 50 years, the average American will look quite racially ambiguous. I have to say that a good sized chunk of me takes a rather perverse pleasure in the assumption subverting affect this may have on people overly invested in the ability to easily categorize and dismiss people based on today’s conventional templates.
Reminds me of the head-exploding looks of confusion I sometimes glimpsed on the faces of people who overheard my white grandchildren (products of my stepson and his wife) call me “grandma” whenever we went out together.