The canyon is much younger than Yellowstone's great caldera. The National Park Service dates its oldest rock and sediment canyon to roughly 160,000 to 140,000 years ago, after the caldera-forming eruption about 630,000 years ago. Hot groundwater altered and weakened the rhyolite; the river then cut through it, leaving the orange, brown, and green bands in the walls.
Lower Falls drops 308 feet. From here it is part of the wider canyon scene, while the Brink viewpoint gives a much closer look at the water.