Cecil Sharp was the founding father of the English folk revival in the beginning of 20th century. When he came to America in 1915 he realized that nearly all of he English folk songs the immigrants had carried with them in America had vanished, replaced by more sophisticated and "educated" versions.
Then he heard abut the Appalachian, the geographical isolation and the strong folk song tradition of the mountaineers. Sharp made three visits to North Carolina, Tennessee, Virginia, and collected 1700 traditional English ballads, including versions that were not being sung in England and Scotland anymore. The whole story is told in this excellent article. The collected ballads included "The House Carpenter", "Barbara Allen", "The Gypsy Laddie", or immigrant songs like "Pretty Saro" (look here for the song's origins).
Dolly Greer - Pretty Saro (buy) (From the album "Doc Watson & Family, 1963)
Dolly Greer is a distant cousin of Doc's. She sings it a cappela, in the open, the way people sang to Sharp in 1917.
Imagine a very British scholar in a 3-piece suit climbing the mountains and meeting with bewildered but cooperative families of mountainers, and you won't be far from the truth.
But when he visited the Appalachian, the place was changing, opening to the outside world. Coal mines were attracting a population of new settlers coming from different parts of the continent and from overseas. This new melting pot was about to give birth to what we now call country music.
Sharp was only interested in the survival of English ballads and didn't pay much attention to native American ballads of any origin.
There's also this controversial quote in his diary :
We tramped - mainly huphill. When we reached the cove we found it peopled by niggers... All our troubles and spent energy for nought.
In his obsession for lost British folklore, Sharp (who was not so sharp-eyed after all) totally missed what was about to happen to American folk music. Nevertheless, his story is a great document to study the origins of country music.
In September of 1916, Sharp collected 26 songs from a Mrs Bruckner in Black Mountain, NC, including "The Farmer's Curst Wife", that Bill & Belle Reed recorded under the name "Old Lady and the Devil" 12 years later. In the mean time, the guitar had begun to replace the banjo.
Bill & Belle Reed - Old Lady and the Devil (buy) (1928)
Find more versions of this song here, on my fellow French roots blogger Gadaya's wonderful site, Old Weird America, entirely devoted to the Harry Smith anthology. It's a real gold (or coal ?) mine !