Hi Alice: That is a great find!
Just in case, the First census of the United States, 1790, Free Black Heads of Families lists several Revil/ Revell families. There may be a connection.
REVELL, Elijah 12 in the family, page 71
REVELL, Micajah 12 in the family page 71
REVIL, Burwell 1 " " " " 49
REVIL, Edmund 9 " " " " 50
REVIL, Nathaniel 13 " " " " 52

In the 1820 North Carolina Census of "Free Colored Heads of Household", there are 14 heads of Families, with various spellings.
REVEL, REVELS, REVELL, REVELLS, REVOLS.