Actually, interracial marriage was not uncommon around the turn of the 19th century and before - it wasn't until later that the fight about slavery became strident and slave owners had to come up with 'moral' arguments to defend it that mixing of the races came to be called 'miscegenation' - a made up word. Before that, people married according to class, not race.
What is unusual is that this one is so well documented.
I am also looking for info on Felson and his progeny. Anyone who has any may contact me at
khalleron@yahoo.com.