The Sevier Orogeny began roughly 165 million years ago in the middle Jurassic and ended approximately 80 million years ago in the late Cretaceous. It was a result of the Farallon plate being subducted under the North American tectonic plate. The process happened so quickly that the rock folded and sheared producing multiple, imbricated, low angle thrust sheets which placed older rocks on top of younger rocks. The Sevier Orogeny starts around the southern part of California and stretches up through Utah and into Wyoming.
The above picture is a good example of the Sevier Orogeny. In it you can see a strange curved deformation in the mountain side. This resulted from the thrusting and buckling that occurred during this time in history.