Hell's Canyon petrified wood. This rare wood, collected in the 1950s at a site now underwater at a dammed river on the Idaho / Oregon border,
had dry rot and was compressed before petrification, creating its characteristic herringbone pattern.
A place for show-and-tell, wondering aloud, and wandering the trails of curiosity . . . Comments, corrrections, additional information, fresh insights, other interpretations, more images, or related observations will be welcomed!