Figure 18.17

Cuestas and hogbacks. (A) Cuestas, such as the Bookcliffs near Grand Junction, Colorado, are formed where sedimentary rock dips less than 30° from horizontal. (B) Hogbacks are composed of erosion-resistant sedimentary rock layers with a dip of 30° or more from horizontal. This hogback is the San Rafael Reef, a steeply tilted layer of sandstone and limestone in eastern Utah.
(A. © Jim Wark/airphotona.com; B. © Francois Gohier/Science Source)