Three of the four semifinal slots in our Archives Treasures tourney are filled after the 1906 Tenino Oregon Trail marker photo eliminated the documents of Washington Territory’s first prison, 55 percent to 45 percent. The marker photo joins the 1969 Black Panther protest photos and the 1980 Mount St. Helens eruption documents in the semis. The fourth semi position will go to the winner of today’s quarterfinal matchup between the Washington territorial seal and 1859-60 Crosby Store ledger.