Figure 9-3: R I V U X G
Earth’s Dynamic Surface These tan-colored ridges, or hogbacks, in Colorado’s Rocky Mountains were once layers of sediment at the bottom of an ancient body of water. Forces within Earth folded this terrain and rotated the layers into a vertical orientation. The layers were revealed when wind and rain eroded away the surrounding material.
Earth’s Dynamic Surface These tan-colored ridges, or hogbacks, in Colorado’s Rocky Mountains were once layers of sediment at the bottom of an ancient body of water. Forces within Earth folded this terrain and rotated the layers into a vertical orientation. The layers were revealed when wind and rain eroded away the surrounding material.
(Mr. Klein/Shutterstock)