Ryndael on Family Tree Circles

I'm researching my paternal line, and am stuck on Jones. Here's what I know:

Ryne Quillen (Me) <- Gregory Alan Quillen (w/Patricia Ann Stafford) <- Earl Richard Quillen (w/Shirley Ann McDaniel) <- Blanche Buna Jones (h/Ira Halder Quillen) <- R M Jones (w/Bettie Williams)

I'd really like to know what RM stands for. I know he was born in October of 1870, in Tennessee. I know his parents were both born in TN as well. But every census from 1900 on and birth record of his children (Ralph M, Leon, Gladys, Evaline) just lists RM.

I did find a census of 1880 that lists Robert M Jones born est. 1870, which lists him as the son of E Absalom Jones and Elizabeth J Jones. But I have no way of knowing for sure whether that's he or not (though they did live in Loudon, as every census lists R M as living as well).

Any help appreciated!