Geologists call the process of canyon formation downcutting. Downcutting occurs as a river carves out a canyon or valley, cutting down into the earth and eroding away rock.

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At Dinosaur National Monument, canyon walls reveal textbook examples of folded and faulted rocks formed during the past two billion years. Many of the 23 rock layers exposed within the monument are visible only in the river canyons. Without the slow, persistent downcutting of the Green River, these impressive, colorful rock layers would lie buried deep beneath the Earth's surface.

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Dinosaur National Monument is known for, of course, an incredible array of dinosaur fossils. And we were also impressed with the beautiful and dramatic landscapes including canyons carved by the Green River.

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