"Brown girl in the ring" has interested me since I came across it in the Sixties, on a 10" LP of Jamaican children's songs. In rural Jamaica everyone is brown so why "brown girl?" English children don't sing about white girls. The colonial history of Jamaica and their memory of slavery may account for their awareness of colour and its hierarchy? The version I heard was in fairly deep dialect, but sounded like "she look like sugar or a plum", which makes more sense than some.