from the floor of Castle Valley, but rather, it’s the valley that’s subsiding around the 700 foot high (210 m) igneous trachyte porphyry stock of Oligocene age.
From left to right, the high La Sal Mountains, Round Mountain, and Porcupine Rim. (Click image to enlarge.)
Learn more about the development of collapsed salt-cored anticlines in the Paradox Basin: Moab salt-intruded anticline, east-central Utah (small PDF download).