Ridges

Tall, narrow ridges snake between mesas and buttes. Where one such ridge crosses a flat-topped mesa (in the lower center of the image), the mesa surface is split into two surfaces of different heights, like a split-level house. This suggests that the ridges, like the mesas and buttes, are erosional remnants of a former surface that has since been mostly stripped away. Some of the buttes appear to be layered. Sand dunes have formed in the loose material left surrounding the buttes, mesas, and ridges.