Originally <a href='http://www.sportsbookreview.com/forum/showthread.php?p=9917909'>posted</a> on 05/08/2011:

Most Irish-Americans did not get here until long after slavery was over. Because the Irish were of similar economic status to the blacks when they got here (many stores had signs along the lines of "Help wanted, no negroes, irish need not apply".) there were a great deal of irish-black couples.

Most of the super anglo names are in fact "slave names" but when a black person has an Irish, Jewish, or German (sometimes) last name it often came to them the traditional way.