Looking for Betti Betty Fletcher

Hi, Iam looking for information on my Great-Great Grandmother, Betty Fletcher. She is believed to be Native American. Betty Married John Whitt and had two children Richard and Hannah. Hannah Married John Evans sometime in the 1890's in Logan Cty Wva. Some of their children are Sarah{my grandmother} Alice and Olice{twins} Julius, Minnie,Betty. 12 children or more. Any information would be greatly appreciated.

D