Original 1st printing 14 x 20&1/4" concert poster for Quicksilver Messenger Service appearing with Mount Rushmore from 6/29-30/1967 and Big Brother and the Holding Company (featuring Janis Joplin) appearing with Blue Cheer from 7/1-2/1967, all shows held at the Avalon Ballroom in San Francisco, CA.
 
 Art by Victor Moscoso, image is # 68 in the Family Dog/Avalon series. 
 
Medium flat index stock poster is in good to very good (B to B/B+) condition; there are numerous pin/staple holes in all four corners and in the top bottom margin, along with a set of light white tape shadows in all four corners, a small soft 2" diagonal roll bend along the lower right margin, a couple of soft corner-tip creases, a few semi-soft handling dings here and there, a light degree of toning and a stray edge ding or two  around the outer margin area, otherwise it is a fine-looking lightly-worn 1st printing example of this mind-boggling Moscoso Avalon poster from mid-1967.