Original 1st printing (Maron Litho credit) 15&3/4 x 23&1/4" concert poster for Quicksilver Messenger Service appearing with Van Morrison, Blue Cheer and Clear Light at the Earl Warren Showgrounds in Santa Barbara, CA on 9/30/1967.
Artist unknown/not credited, medium-thin flat vellum stock poster is in excellent (B+) condition; there are a couple of very soft roll bends/light edge creases going around all four margins, a slight fading to the yellow pass of ink on the right side of the image, a couple of thin diagonal/vertical bends in the upper left margin, a few stray surface dings and a whisper of handling, otherwise fine.
Very cool original 1967 poster from the Jim Salzer series; check out a great informative list of 1960's-era shows (including this one) at the Earl Warren Showgrounds: