She calls it “Ameri-Celtic-Cana.” That stands for Americana with a Celtic Twist. Helen O’Shea first heard about The Stone Pony back in her native Ireland during her obsessive Bruce phase as she attended medical school in Galway. Her taking the Stone Pony iconic stage this Saturday is a dream-come-true. It’s an all-day show with plenty of other artists. Her set is at 3:00 in the afternoon.