The tune for The Great Silkie of Sule Kerry reappeared in the mid sixties on the Byrd's album 5D as the melody for the Hakim Nizmet poem "I Come and Stand at Every Door." I don't know if this was the first appearance of this poem/melody combination. This song was often heard in coffee houses, at protests etc during the 60s, and I didn't realize the tune was traditional until I heard Art Theime sing it on his album "The Older I Get the Better Was".
More on the Nizmet poem here.