The subject was the son of Thomas S. Watson, Jr., and Sallie Donelson Smith of Davidson County, TN. He was the grandson of Thomas S. Watson, Sr., and Sally Sanders and of Col. George Smith and Tabitha Donelson. Great-grandson of General Daniel Smith of "Rock Castle" and of Captain John Donelson, III.
Another viewer writes: From my records, Eugene Boyd Watson was the son of Winfield Scott Watson (1820-1871) and Sara A (1822). He was the grandson of Thomas Watson Sr. (1795-1871) and Sally Smith (d.1840) His father Winfield, was the brother of my great-great grandfather, Washington Boyd Watson. It does get complicated!
Any other clarification of dates and lineage would be welcome.