Anza-Borrego Desert Pix
The Anticline in Fish Creek
Heading westward through the Split Mountain divide is a geologist's playground full of red dirt, giant rock formations and wind caves. The cliffs are chock full of ancient rocks. This rock and mud mixture is called fanglomerate and is approximately 20 million years old.
The best spot to observe the chaos is a place called the anticline where rock plates are stacked on top of each other and resemble stacks of crazy kitchen plates. You can see how the plates have been forced up and down by the weight on top of them and form a kind of arch in the cliff face.
The geology along this trail was beautifully described by the late Dr. Horace Paker in his Anza-Borrego guidebook. He wrote that: "Split Mountain's height and mass forms awesome patterns, constantly drawing one's eyes upward to search for new points of interest along the canyon's walls. Geologically speaking, Mother Nature went berserk mixing a potpourri of her many arts. There are granites and lava dikes, sandstones and mudstone, marine deposits and fresh-water deposits, anticlines and synclines, hanging walls and footwalls, fault zones and landslides, with igneous, sedimentary and metamorphic rocks and combinations of each. And to top if off, she made a special plum pudding called Split Mountain fanglomerate, in which worn and rounded stones, like raisins, are embedded in a matrix of sandstone alluvium. To add a touch of humor, she liberally garnished the area with ridiculously formed sandstone concretions. Then she cut, sculptured, and tilted the entire mess into a rock-candy pattern of canyons, washes, and broad valleys."
I never get tired of this trail and you can actually leapfrog a series of trails from here (including Valecito Wash and Dos Cabezas Road) which will take you almost 50 miles south to Ocotillo. Be aware that a small section of this route will be through the challeging Diablo drop-off. This is a narrow slot with large wheel ruts and has a class five difficulty rating.