Stretching back from the rim of a dramatic desert canyon carved by the Columbia River, this 7,500-acre state park preserves a remarkable variety of petrified trees which were buried within the massive lava flows that created the Columbia Plateau about 17 million years ago. It is one of the most extensive, and certainly the most varied petrified forest ever discovered in the US. Perched at the edge of the canyon, the interpretive center houses exhibits that explain the petrifaction process and advance theories for how so many different species of trees came to rest here. Displays include more than 50 varieties of petrified wood, some presented as logs and stumps, others as crosscut sections which reveal intriguing details such as growth rings and cracks.