"The song first appeared in writing as "Shenadore" in The New Dominion Monthly in April, 1876."
We, on Mudcat, know this isn't true. A version of Wikipedia had that "first" but I removed it back around 2014. So, Ballad of America website is just cribbing from Wiki and now, in reposting that, we reinforce an error.

"The author, Captain Robert Chamblet Adams, indicated that he had first heard the song around 1850."
No idea where they got this from. I never saw that in Adams' text. (If I missed it, I'd really like to know!) Moreover, AFAIK Adams' sea experiences began in the second half of the 1860s. He was born in 1839, so where was he hearing "Shenandoah" in 1850 at age 11?

"W.B. Whall reprinted it..."
I would think "reprinted" means that Whall took what was printed in Adams and printed it again. But Whall just gave a version of the song, as many already had before. The piece goes on to say that Whall's was "likely" the original version. Um, ok.

"Most musicologists agree that the chief mentioned in "Shenandoah" is the Oneida Iroquois chief John Skenandoa."
No they don't. Who are these "musicologists"? Whall made up that "Skenandoa" thing, so maybe a bunch of people repeated that (like Ballad of America is doing), but those people aren't "musicologists" nor are they "agreeing"—those words imply they have done independent research and it led them to a similar finding, but not a single musicologist has done that.

Seems convenient for such pieces to often platform the outlier "Indian chief" thing but ignore, for example, Adams' "Shanadore's a bright mulato." No one curious how Shenandoah turned (according to their timeline) from an "Indian chief" to a "mulatto"?