Below 3,000 feet, the Colorado Desert, occupying the eastern half of the park, is dominated by the abundant creosote bush. Adding interest to this arid land are small strands of spidery ocotillo and jumping cholla cactus. The higher, moister, and slightly cooler Mojave Desert is the special habitat of the undisciplined-looking Joshua tree, extensive strands of which occur throughout the western half of the park. Standing like islands in a desolate sea, the oases provide dramatic contrast to their arid surroundings. Five fan palm oases dot the park, indicating those few areas where water occurs naturally at or near the surface to meet the life requirements of these stately trees.
Oases once serving earlier desert visitors now abound in wildlife.
The park encompasses some of the most interesting geologic displays found in the California's deserts. Exposed granite monoliths and rugged mountains of twisted rock testify to the power of the earth forces that shaped this land. Washes, playas, alluvial fans, interact to form a giant desert mosaic of immense beauty and complexity. As old as the desert may look, it is but a temporary phenomenon in the incomprehensible time- scale of geology. During the pleistocene, one of the Southwest's earliest cultures, the Pinto people, lived here, hunting and gathering along a slow-moving river that ran through the now dry Pinto Basin.