My footnote to the previous post:

The editor of the book "Anecdotes, poetry,...etc." seems to take it for granted that the diarist William H. Landreth composed the song (or poem) himself. The index entry for that song says:

"The new river shore, a ballad, by W. H. Landrith [sic], [page] 180"

I doubt it. More likely, he took it down from the singing of a fellow soldier. The incongruous last verse is enough evidence that the song has already been folk-processed.