Wishbone Ash

As sometimes happens to long-running classic rock bands that endure complicated lineup changes, there are now two competing touring formations of the seminal prog-rock group Wishbone Ash. The one that plays Shank Hall tonight is the more established, better regarded of the two, led by original guitarist Andy Powell. When Powell seized control of the band in the mid-'90s, he led the group in some unorthodox directionsinfamously recording a pair of dance-inspired records that weirded out longtime fansbut he's since returned the group to its roots, recording a number of nostalgic live albums and a few back-to-basics prog albums, including last year's <i>Elegant Stealth</i>. <P>