oldest recorded mountain dulcimer songs

What is the oldest recorded mountain dulcimer song that anyone knows about?

I know the Library of Congress has a lot but they can be hard to wade through and I've found that not everything they have cataloged is available digitally unless you have the means and desire to pay them a LOT to make it available. Not complaining about that mind you, just stating a fact.

The oldest I have on my iPod are by Tom West recorded in 1934. I'm assuming there are others out there that pre-date but I don't know.