page_title: Paleontology in Oregon
section_title: Cenozoic Era
hierarchical_section_title: Paleontology in Oregon / Cenozoic Era
caption_attribution_description: English: mount of Patriofelis, currently in storage in the collections of the Dept of Vert Paleo, American Museum of Natural History
context_page_description: Paleontology in Oregon refers to paleontological research occurring within or conducted by people from the U.S. state of Oregon. Oregon's geologic record extends back approximately 400 million years ago to the Devonian period, before which time the state's landmass was likely submerged under water. Sediment records show that Oregon remained mostly submerged until the Paleocene period. The state's earliest fossil record includes plants, corals, and conodonts. Oregon was covered by seaways and volcanic islands during the Mesozoic era. Fossils from this period include marine plants, invertebrates, ichthyosaurs, pterosaurs, and traces such as invertebrate burrows. During the Cenozoic, Oregon's climate gradually cooled and eventually yielded the environments now found in the state. The era's fossils include marine and terrestrial plants, invertebrates, fish, amphibians, turtles, birds, mammals, and traces such as eggs and animal tracks.
  Oregon has a long tradition of paleontological research. Local Native Americans devised myths to explain fossils.
context_section_description: Oregon's paleoenvironment in the Cenozoic reflected the era's overall global cooling trend, shifting from tropical to temperate to glacial climates. Westward shift in the state's shoreline brought a more diverse terrestrial fauna, including a variety of extinct land mammals.
  The state's earliest Paleogene deposits record an environment that was warm and wet, similar to the modern American southeast. Fossils from this time include pollen and leaves from ferns, spongeplants, hazelnuts, water elms, laurels, and horsetails. Trees that would become more common when temperatures later cooled, including alder and birch, made their first appearance along Oregon's Paleogene coastline. Invertebrate foramenifera from the Paleogene have been reported from sediments in Coos County, but their identity remains disputed.
  Oregon's mid-to-late Paleogene fossil record is split between the ocean-covered western part of the state and the terrestrial east, where mammals made their first appearance in the state's fossil record.
  
  In western Oregon's ocean, the new Cascadia subduction zone laid the foundations for Oregon's modern Coast Range and improved ocean productivity, prompting diversification among the state's fauna. At least 25 species of mollusk, including several snails, are known from the Fern Ridge Dam area alone. Other marine invertebrates include echinoderms, foramenifera, brachiopods, scaphopods, shrimp, and crabs. Shark teeth from over a dozen genera have been found at a variety of sites, including the Rocky Point Quarry to the west of the Nehalem River. These genera include dogfish, horn sharks, comb-toothed sharks, makos, tiger sharks, white sharks, and an archaic basking shark. Bony fish included mahi mahi, conger eels, rattails, ancestral billfish, cod, hake, and rockfish. Marine birds in the area included auks, the local species Hydrotherikornis oregonus, and the pelican-like Phocavis maritimus. The state's only known fossil egg was found in associated rock formations.
  The subduction zone's volcanic activity also formed the Cascade volcanic arc, which blocked moist air from the Pacific and created the state's High Desert. This is when Oregon's fossil-rich John Day Fossil Beds were first laid down. The earliest fossils in John Day indicate a subtropical terrestrial environment. The assemblage is rich in fossil seeds, fruit nuts, and associated woods, and is one of the few places in the world where all three are preserved in a single location. The flora included cinnamon, cycads, palms, the primitive sycamore Platanophyllum angustilobus, walnuts, magnolias, figs, grapes, coffee trees, cashews, and bananas. The state's earliest known land mammals—including the rhinoceros Hyrachyus, the early horse Orohippus, and the brontothere Telmatherium—browsed these flora. Among the area's predators was Patriofelis, a cat-like creodont. These mammals shared the ecosystem with crocodiles in the genus Pristichampsus and the tortoise Hadrianus.
  In the transition from the late Paleogene to the Neogene period, Oregon's climate became drier and its environments became more similar to those of the modern day. Grasses appeared and spread across the landscape, leaving fossilized leaves in the John Day beds. Metasequoia occidentalis, a conifer closely related to modern redwoods, flourished across the state during this time. Mammals and other fauna diversified and became more common. Early additions included camels such as Paratylopus and Gentilicamelus and pecora such as Hypertragulus. Later additions included perissodactyls such as Merychippus, Parahippus, Protapirus, and Diceratherium, artiodactyls such as Dromomeryx and Blastomeryx, and proboscids like Gomphotherium and Platybelodon. Rodents including the burrowing beaver Palaeocastor and horned gopher Mylagaulus. Predators in this time period included bear-dogs such as Amphicyon, cat-like nimravids, enteldonts, and early canids such as Cormocyon. Remains of the early primate Ekgmowechashala have also been found in the John Day fossil beds.
  Aquatic mammals made their first appearance in Oregon al
caption: A Patriofelis skeleton
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