California was a region of geologic upheaval during the Mesozoic, including both Mountain formation and volcanism. The Sierra Nevada began forming at this time. Mesozoic California included areas of both marine and terrestrial environments. The local seas were home to a variety of marine invertebrates and marine reptiles. The terrestrial flora included plants such as conifers, cycads, and ginkgoes. Radiolaria were widespread in California during the Jurassic. Some of the best fossilized specimens come from the Stow Lake area and Strawberry Hill in Golden Gate Park. During the Cretaceous invertebrates such as ammonites and pearl oysters lived in California. Both coiled and uncoiled ammonites were preserved in California's Late Cretaceous deposits. During the Late Campanian and Maastrichtian California was home to evolutionarily advanced mosasaurs including Plesiotylosaurus and Plotosaurus. On land, a variety of dinosaurs inhabited the state. Among them were the ankylosaur Aletopelta, and many duck-billed dinosaurs, most notably Augustynolophus.