Thanks very much for all of the input! I am currently writing a master's thesis (for my musicology MM) on Peter, Paul, & Mary's career during the 1960s, and the reason for my question had been exactly that which Joe Offer brought up--were they the first to use the Version 2 lyrics of Go Tell it On the Mountain? My experience with 1960s copyright thus far has shown that it did not take much musical or textual alteration to be able to credit authorship to oneself. Perhaps the change in title ("Tell it on the Mountain") or the particular vocal harmonies were enough to obtain the authorship copyright.

The posted suggestions have been very helpful! I will check into Fannie Lou Hamer, and I'm glad to know about Wade in the Water. I will be sure to post if (hopefully when) I find out whether Hammer or PP&M used the lyrics first!

-cmiller