I have no idea how
Jemima apparently became thought of as a black name. Before the Civil War, there were plenty of white American women named
Jemima.
Daniel Boone had a daughter named
Jemima, and they were pretty obviously white.
This might be off-topic, I actually noticed that Old Testament names like
Jemima grew much less common after the Civil War. I wonder why? My theory is that when a lot of the common medieval names (usually of Germanic origin) like
Ida,
Emma, and
Roger were revived, Biblical names like
Jemima,
Ezekiel, and
Tabitha were pushed aside and neglected.
Jemima may have been revived if it weren't for Aunt
Jemima.