Contrary to various recording labels, Garcia did not sit in w/ Yogi Phlegm on 12/31/71, but only on 3/5/72. Bill Vitt had apparently left the Sons/Yogi Phlegm by this point, but generally we would welcome additions or corrections to the personnel listing.
cryptdev: The Grateful Dead - Shows in California March to December, 1972. "The Sons of Champlin, still operating under the name Yogi Phlegm, were scheduled to open the show. However, guitarist Terry Haggerty, vibes player Geoff Palmer, and bassist David Shallock were seriously delayed, ostensibly caught in traffic, and Bill Graham wanted to keep the lengthy show as on schedule as possible, so the rest of the band recruited a couple of the musicians in the green room to temporarily fill out their ranks. Thus the show opened with the quartet of Bill Champlin, Bill Vitt, Phil Lesh, and Jerry Garcia jamming out on a medley of “Big Boss Man” and “How Blue Can You Get.” At the conclusion of those songs, the other two Phlegmatic musicians took the stage, and Jerry and Phil went back to whatever they were doing earlier."