The width and distinctive shape of the vast gorge of the Colorado River result from how its greatly varied types of rock resist erosion. Harder rocks erode to cliffs. Softer rocks erode to slopes. Various minerals, most containing iron, give Grand Canyon rocks their subtle red, yellow, and g...
Gunnison, city, seat (1880) of Gunnison county, west-central Colorado, U.S. It lies along the Gunnison River, just north of the San Juan Mountains of the Rockies, at an elevation of 7,703 feet (2,348 metres). Lying between the Sawatch Range and the Elk M