Ummmmm... G, C, D and occasionally Em.
Seriously, Gary, most of GBS's repertoire is traditional Newfoundland songs, which they don't have any ownership of. Try searching for a particular song by title (or lyric fragment--use the search engine at the top of the page thar) rather than posing such a broad request.
A great big sea hove in Long Beach Right fa-lor, fa diddle diddle di do; A great big sea hove in Long Beach And Granny Snooks she lost her speech To me right fal diddle fal dee.
Bill