Loma Dennis, b. De Queen, AR ~1911

I am looking for info on this Dennis family. Loma is still living but has Alzheimer's. It has been said that she was half Indian and lived at some point on a reservation. Her father was ??? Dennis and her mother was Indian. Someone said it was Blackfoot but I think they were all in the upper midwest and Canada and not anywhere near Arkansas. Loma married
1) William Marshall, probably in Hot Springs and had three sons that I know of: James, Charles and Thomas
2)?? (Name started with R, I think)
3) H. Milton Davis in Union County.
Does any of this sound right to anyone?
Thanks,
Dianne