No worries about difficulties finding it, Rex, the 'cat can be wily sometimes.

Link to the book Rex mentioned: Army and Navy Journal Vol 45, p. 167

Here's another link to the cavalry: via Journal of the U.S. Cavalry Association July 1910, pp. 204-205. The article as a whole talks of Lomax's work of preserving the ballads and inquires readers to send in copies of old folk songs they may have, alluding that "Wild Missouri" may be one that could be lost soon. (as an aside, it also refers to a song "that was about, or referred to 'Aransas Bay' " that had not been heard since the 1880s ... any clues what song that could be?)