406

Many of the bluffs here have layers of sandstone that tilt up and down at different angles. What caused that?

Answer:

This is called cross bedding, a structure formed in windblown sand dunes. As the sand is blown up the dune, it slides down the other side, forming layers. As the dunes move, the place where the layers form shifts. We saw patterns exactly like this in the dunes at White Sands.

Long ago, these rocks were sand dunes in a desert that covered much of Utah, Arizona, and Nevada, and this cross bed pattern is common across the area.

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