"Rock Salt and Nails" is a moody lyric piece by Bruce "Utah" Philips (1935–2008), the self-described "Golden Voice of the Great Southwest".
On the sleeve-notes on the back of Sorrels' album Rosalie's Songbag, Rosalie says the following:
"'Rock Salt and Nails' is another of Bruce Phillips' songs. He taught it to me one night right after he thought it up, and then when I sang it back to him sometime later, he made me a gift of it. It is one of my most prized possessions. He tells me the tune is pretty close to Carter Stanley's 'Lonesome River'."
I may have learned it from Joan Baez.