Hi Judy,
Not sure if I've ever emailed you before, but Belle Cogburn was my G Grandmother. My Mom and Aunts used to talk about Nathan James Johnson also, and the mineral rights retained by Nathan for the texas land that later produced oil. I remember my Mom always said that my 4th Great Grandfater was a full blooded Cherokee indian, if that helps. feel free to email me. I think I may renew my membership on Ancestry.com It's been awhile since I've done any research.
Take Care!
Annette