Just learned that Powell St. John, whose songs were recorded by the 13th Floor Elevators ("Kingdom Of Heaven", "You Don't Know", "Slide Machine", "Monkey Island", a couple others), Big Brother & The Holding Company ("Bye Bye Baby" - Powell and Janis had been in a folk group together in Austin in the early '60s), and Tracy Nelson's Mother Earth (of which he was briefly a member), passed away a few days ago.