How to search Alabama 1866 Census for only blank last name?

Judith Bramlage

I am working on Wikitree's US Black Heritage project where we are trying to gather resources and relationships of Black Americans. I just finished the Dallas County, Alabama 1866 Census for last names of letters A-L and working on M-Z. But that doesn't include all the blank last names. How do I extract them?

Yvonnewedgworth

It's very helpful that Wikitree has a US Black Heritage project, but Familysearch is actually not affiliated with Wikitree.