Turtle Island Quartet brings Coltrane, not Beethoven, to Chautauqua by Philip de Oliveira on July 2, 2017 share Don’t call Turtle Island Quartet a crossover group. “We’re not ‘crossing over,’ ” said founder and violinist David Balakrishnan. “We’re already there.” Turtle Island will perform John Coltrane’s magnum opus, A Love Supreme, along with other