Poster printed in four colors, 20 ¼”h x 28 ¼”w at neat line plus margins. Folds as issued, with wear at a couple of intersections. Tack holes in corners, and signs of removal, perhaps from an issue of Mother Earth News. Tear at bottom right corner area. 

The only reference of this that I have found was a copy that was sold on the 'Boston Rare Maps' web-site. Google it, it gives a great explanation of this site.