Here's some spooky southern folklore, courtesy of the Midway Museum.
However, as the wall was completed and the grave began to settle, a crack in the wall developed. Multiple attempts were made to repair the wall, but each time the crack determinedly reappeared. Finally, the ground below was dug up and the slave’s bones were discovered and removed.
However, even after refilling the ground and repairing the crack one final time, it reappeared. It is recorded that an elderly black local once explained the legend of the crack, “Ain’t no use fer de white folks fer men’um. Dat hant gwine crack um fas’ es it get fix.”
Posts are a combination of my own research, visits, and conversations, plus various information found around the web. I try to provide sources, but if you have specific questions, feel free to ask!