Cowboy Waltz(the tune)was learned from Woody Guthrie. When I played the tune for Uncle Jeff Guthrie(who taught Woody how to play) he exclaimed, "That's not 'The Cowboy Waltz', that's the 'McGreevey(?)
Waltz!". Telling the story to John Cohen, he informed me that the tune is also known as the "Green Valley Waltz".

Mark Ross