undifferentiated rock units

Paleontology and geology

During the Devonian, most of what is now California was still under water. Scattered exposures of Devonian shale, sandstone, limestone, and dolostone can be found in the Northern Sierra Nevada, as well as to the south in the White Mountains, Inyo Mountains, and places around Death Valley. Exposures of Devonian-age rocks are not common in California, and the few fossils collected have been mainly invertebrates: brachiopods, corals, stromatoporoids (sponge-like animals with calcareous skeletons), ammonites, crinoids.