Paleontology and geology
During the Early Jurassic, the northwestern part of the state remained an ocean basin, and a volcanic island arc formed in this region. Shallow marine limestone, siltstone, and sandstone were deposited in the central part of the state. These rocks are the youngest marine sediments in Nevada. Later in this period, tectonic activity continued to the north and west, and deep marine deposits were thrust eastward onto the shallow marine shelf. Granite plutons began intruding the crust during and after this tectonic activity. They can be found scattered through the western, central, and northeastern regions of the state. In the south and along the easternmost edge of the state, non marine deposits, including sand dunes, accumulated through the Jurassic. Fossils are limited, but include pectens, oysters, and ammonites. This map indicates exposures of Jurassic rocks in the north-central and southwestern sections of the state.