I just checked out some information I had from a guy in Oklahoma - if it pans out, let me know & I'll send him your e-mail address.
He wrote and told me ---
I will tell you what I know about the Thomas that I know is related to me. He is the one that died at about 30 years ole. He was my grandpaws ( Joseph William Robertson ) younger brother. He was born, probably in Hawkins county Tennessee, 7/10/1860. His name was Thomas N. Robertson, and married a girl named Katy Miller. She was a sister to my grandmother, Dora Miller. He is shown to be 6 months old in the 1860, Hawkins county census. They are all listed as Robinsons, though, as I think I had told you before.
He says they went to McKinney TX and were there from around 1892 for several years.