From an Ebay auction description: This is a super rare original handbill for "Bedrock One" in a rare variant color (deep gold) - most of the handbills for this event are light green. This was supposed to have been a Digger’s event, however, The Diggers disavowed any connection and as a result many copies of the handbill have text overprinted on the back stating it is not a Digger’s event. This handbill is blank on the back.
Bedrock One which took place on March 5th, 1967 at California Hall in San Francisco, California featured music by Steve Miller Blues Blues Band, Dino Valenti; ceremonies from The Radha Krishna Temple; poetry by Richard Brautigan and The Caped Crusaders; experimental theater, lights, and happenings by the S.F. Mime Troupe. Hosted by Warren Hinkle III, editor of Ramparts Magazine. The artwork is by fabled Underground (Zap and other comix) Comic artist, Robert Crumb - he hardly ever did artwork for concerts so this is a rare R. Crumb piece. 8 1/2 x 11 inches and in Near Mint condition. | 
