Official promoter-issued 1967 3rd printing 14 x 20" concert poster for the Grateful Dead appearing with Oxford Circle at the Avalon Ballroom in San Francisco, CA from 9/16-17/1966.
Art by Stanley Mouse and Alton Kelley (central image borrowed from Edmund Sullivan), image ("Skeleton and Roses") is # 26 in the Family Dog/Avalon series.
Medium flat index stock poster is in excellent (B+) condition; with the exception of a few light handling creases here and there, a series of VERY light pin-prick spots along the right margin and a trace of corner-tip/edge wear, it is a fairly bright/clean example of the classic "Skeleton and Roses" image that won't break the bank.
Have a listen to the 9/16 show (PRIMAL '66 Dead) HERE:
https://archive.org/details/gd1966-09-16.vintagedead.25283.sbeok.shnf