history of the song "Shenandoah"

[Eric Peterson]

My Readers Digest Family Songbook (c1969) says this: "A short-haul
chanty dearly loved by sailors on square-rigged ships, "Shenandoah"
tells of the love of a white man for the daughter of the Indian
chief after whom Virginia's Shenandoah Valley was named. The song
had originated as a land ballad sung by lumberjacks who brought it
down to the river and introduced it to the seafaring men."
These series of songbooks are amazing for their guitar and
piano charts. I love these songbooks -- and the intoductions to
the songs (all songs that were significant to different eras),
compiled by Stanely Green all seem to be accurate and meaningful.
But is there a mistake here or not?
One thing though -- according to Stanely Green, Shenandoah is an
Indian word. And that should be varifiable. Sounds like it could
be Indian to me. I don't know if I buy the Pochahontis(poor
spelling) though. But what can you say about the Valley that is
named Shenandoah?