Looking into the complex of chasms in northeast Oregon's Imnaha Canyonlands. Exposed in these canyon walls is the stack of lava flows known as the Columbia River Basalt Formation, one of the world's greatest outpourings of lava. The eruptions recorded here from about 16 to 14 million years ago occurred at intervals of about 10,000 years. If people had been around in those days, there would have been time following one eruption for about 500 generations of humans before their graves were buried by the next eruption. Photographed on 4x5 from near Indian Village.