It all happened at the Rainbow Gardens in Pomona, California, 1960, as THE MIXTURES, mighty kings of the West Coast's Eastside dance hall scene, rocked and ruled the house. As the movement for integration that began in Mississippi and Alabama was taking shape nationwide, it was not only the South that was segregated. In the Southern California of the Fifties, non-white races were more allied, though it was rare you'd find them mixed in a band. As the dawn broke on rock 'n' roll, "The Mixtures," a six man party band- was at different times comprised of African