Thank you very much for your reply. Yes, my Rankin Monroe did marry Nelly Hart. And much of my family lived in Henry, Maury and Hickman Counties. My family surnames include: Gill, Dorton and Head among others.
I have read much information naming different fathers for Oliver and have been trying to sort through it. Although disappointing, it is good to know that this information is still unproven. It keeps me from going on a wild goose chase.