Hi - This is Melinda again - On the earlier Census's there was not a "native American" or "Indian" option for "race" - it was either "white", "black", or "mulatto". "Black" did not necessarily mean "African American" - it was just referring to the color of their skin. And "mulatto" did not nescessarily mean a mixture of "white" and "African American."
The Census taker used their own "opinion" of the "color" of a person, which is why sometimes on one Census they will be described as "mulatto", and on another "black".
In other words, a person identified as "black" on an early Census could have been "African American" or "Native American". or any race that had darker skin.
I hope this helps you in your search. Sincerely, Melinda