The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over 210,000 km2 mainly eastern Oregon and Washington, wes
The Columbia River Basalt Group (including the Steen and Picture Gorge basalts) extends over portions of four states.
Restoration of Miocene animals at the Picture Gorge Basalts
In the Palouse River Canyon just downstream of Palouse Falls, the Sentinel Bluffs flows of the Grand Ronde Formation can be seen on the bottom, covered by the Ginkgo Flow of the Wanapum Basalt.
Location of Yellowstone Hotspot in millions of Years Ago