This is the end of the Keystone Thrust Trail, marked by a signpost on a rounded ridge. The Keystone Thrust is a gigantic fault created by two plate tectonics colliding millions of years ago. This resulted in the much older, gray limestone being pushed on top of the younger, newer red sandstone. The Keystone Thrust is one of the most dramatic and accessible examples of this geological process in the United States.
Although the Keystone Thrust can be viewed elsewhere in the park, this end point of the Keystone Thrust Trail provides you with a clear cross-section of the two types of rock, with the older pushed on top of the younger. Even if you are not a geology nerd, the view of the gray limestone of the La Madres and Turtlehead Peak, contrasted against the red sandstone of Calico Hills is striking and well worth the hike!
From this highpoint on a rounded ridge line, as you head back to the trailhead, you also get amazing views of the rest of the mountains and canyons in the park including a great view of White Rock.