The Sevier Thrust Belt

Not an exercise machine, it's the geologic mega-feature I kept seeing during my recent visit to Las Vegas and surroundings. The Sevier belt is a long zone where, during the Cretaceous, huge sheets of rock were propelled slowly over the top of younger rocks to the east. In the Las Vegas region, the top of the thrust is dark gray limestone and the underside—the footwall of the thrust—is red sandstone. This really makes the thrust stand out. See a new photo gallery of this feature.