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. By the mid-19th century local fossils had come to the attention of formally trained scientists, and modern research has produced data on climate change and extinction.
The Oligocene dawn redwood Metasequoia occidentalis is the Oregon state fossil.
Prehisto Precambrian There are no known rocks in Oregon from Precambrian times. Geologists infer that the area now occupied by Oregon must have been submerged deep on the ocean floor during that period. [1]
Oregon's oldest known rock formations are found in the Blue Mountains and the Klamath Mountains. [2] [3] The state's oldest individual rock is a limestone near Suplee dated to nearly 400 million years ago, during the Devonian period of the Paleozoic era. These deposits include conodonts as well as extinct corals and brachiopods, indicating a shallow marine environment. [2] Most of Oregon would remain under water until the Cenozoic era.
Starting in the Carboniferous period, a series of volcanic archipelagos formed in the region. [2] Islands in these chains would have hosted warm, wet terrestrial environments. [1] Fossils in Oregon's oldest floral assemblage, dating to the Late Carboniferous period, implies a lagoon ecosystem. [4] Fossils in the assemblage include horsetails, ferns, scale trees, and conifer tree seeds. [5] Formations of similar age also include shallow water invertebrates indicating that Oregon's volcanic islands were surrounded by coral reefs, which is consistent with Charles Darwin's theory of reef formation. [4]
Island chains continued to form over Oregon through the Permian period. [3] Fossil assemblages from that time are therefore similar to those from the Carboniferous, although none have been found that include any Permian plant life. One species of Permian snail found in Oregon, Acteonina permiana , lends credence to the theory of plate tectonics because of its resemblance to contemporary Eurasian species. [4] [6] Fragmentary remains of Permian trilobites, including the endemic species Cummingella oregonensis , have been found in the state's Coyote Butte Formation. [4] [7]
Oregon remained covered by shallow seaways throughout the Mesozoic era. Rising temperatures throughout the era led to rising sea levels. Oregon's fossil flora and fauna track these environmental changes with the addition of species adapted to deeper water or more tropical terrestrial conditions.
A new series of tropical islands emerged during the Triassic period, formed by the merging of the state's older volcanic chains. [3] The only plant fossil from Oregon's Triassic formations is Diplopora oregonensis . [8] As in the Paleozoic, shallow water invertebrates made up Oregon's Triassic fauna. These include sponges, ammonites, radiolarians, brachiopods, and the belemnite Aulacoceras . The trace fossil Chondrites , a species of fodinichnid, has been found in the same formations. Although corals have also been found in these assemblages, paleontologists debate the presence of true coral reefs in the region during the Triassic. [4] [9] The oldest vertebrate fossils in Oregon's fossil record appear in Triassic-aged limestones in the Wallowa Mountains. These fossils, including vertebrae, ribs, and a partial skull, have been assigned to the early ichthyosaur genus Shastasaurus. [4] [10] Additionally, a new genus of basal thalattosaur has been recovered from the Brisbois Member of the Vester Formation in Central Oregon near the community of Suplee. [11]
The breakup of the Pangaean supercontinent during the transition to the Jurassic period created a subduction zone in Oregon's ancient seaway, burying older rock formations and giving way to new volcanic island chains. [3] Oregon's Jurassic invertebrates, such as the reef-building clam Lithiolus problematicus and the mussel-like Buchia piochii, indicate shallow sea environments similar to those of the state's late Triassic. Among Oregon's Jurassic-aged vertebrate fossils are the remains of marine crocodiles known as Zoneait. [12] [13] These crocodiles likely shared Oregon's Jurassic seaways with ichthyosaurs. [4] Plant fossils from Oregon's Jurassic period show that the terrestrial environment became warmer and wetter, creating swampy conditions. These fossils, from the Coon Hollow Formation and others of similar age, include ferns, quillworts, cycads, and conifers. [1] [4]
Oregon's islands collided with the Laramidian continent at the end of the Jurassic, creating a new western coastline during the Cretaceous period. [2] This coastline later developed through a combination of sea level change and mountain uplift. Global temperatures reached their maximum during the mid-Cretaceous, melting mountain ice and increasing global sea levels. As sea levels rose the Pacific grew to cover more of Oregon's landmass, eventually stopping at the base of a coastal mountain range. [2] [3] These mountains blocked oceanic weather systems, creating a tropical rainy environment along the ancient Oregonian coast. [4] Although the mountain range ran along that Cretaceous coast, it was different from Oregon's modern Coast Range. [1]
Because of the spread of seaways over Oregon during the Cretaceous, plant remains from that time period tend to be rare in the region. Those that have been found come from the state's southwest and northeast, which indicate the presence of small islands in those areas during the period. Plant fossils from these areas tend to be endemic to the region. These include species of the fern Dicksonia , cycads Ctenis and Ctenophyllum , conifers Podozamites and Taxites, seeds of the palm Attalea , and the tree-fern Tempskya . The tree-fern fossils have been found associated with ammonites, suggesting the location of an ancient shoreline. Other Cretaceous invertebrates in the region are similar to those found in Jurassic formations. Cretaceous formations in Oregon tend to include a wider variety of trace fossils, including the fodinichnids Planolites , Skolithos , Glossifungites, and Arenicolites. [4] Oregon's oldest known crustacean, a unique species named Hoploparia riddlensis , is also of Cretaceous age. [14]
Oregon's vertebrates become more diverse in its Cretaceous fossil record. An amateur discovery in 2005, popularly dubbed "Mitchell's Monster," shows that short-necked plesiosaurs roamed the state's Cretaceous seas along with ichthyosaurs. [1] [15] Other sites nearby in Wheeler County have yielded the remains of Oregon's only known pterosaur, attributed to Bennettazhia oregonensis, as well as teeth from the extinct goblin shark Scapanorhynchus. Only two non-avian dinosaur fossils have been found in Oregon, and both are isolated bones in marine rocks, which evidently bloated and floated out to sea. One is the pedal phalanx of a large (5 m long) ornithopod, intermediate in size and morphology between Tenontosaurus and Eolambia , from the Early Cretaceous (Albian) Hudspeth Shale near Mitchell, Oregon. [16] The other is a sacrum fragment, attributable to a hadrosaur similar to Lambeosaurus , recovered from Late Cretaceous (Campanian) sandstones at Cape Sebastian on the southern Oregon coast. [17]
There is no geological record in Oregon of the K-Pg boundary or of the event that ended the Mesozoic era. [2] [3]
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. [2] 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. [18] Invertebrate foramenifera from the Paleogene have been reported from sediments in Coos County, but their identity remains disputed. [19] [20] [4]
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. [4] At least 25 species of mollusk, including several snails, are known from the Fern Ridge Dam area alone. [21] Other marine invertebrates include echinoderms, foramenifera, brachiopods, scaphopods, shrimp, and crabs. [4] 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. [22] Bony fish included mahi mahi, conger eels, rattails, ancestral billfish, cod, hake, and rockfish. [4] Marine birds in the area included auks, the local species Hydrotherikornis oregonus, and the pelican-like Phocavis maritimus. [23] [24] The state's only known fossil egg was found in associated rock formations. [4]
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. [3] This is when Oregon's fossil-rich John Day Fossil Beds were first laid down. [25] 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. [26] The flora included cinnamon, cycads, palms, the primitive sycamore Platanophyllum angustilobus, walnuts, magnolias, figs, grapes, coffee trees, cashews, and bananas. [2] 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. [27] [28] These mammals shared the ecosystem with crocodiles in the genus Pristichampsus and the tortoise Hadrianus. [4]
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. [2] [29] Metasequoia occidentalis, a conifer closely related to modern redwoods, flourished across the state during this time. [2] [4] Mammals and other fauna diversified and became more common. [30] 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. [4] Remains of the early primate Ekgmowechashala have also been found in the John Day fossil beds. [31]
Aquatic mammals made their first appearance in Oregon along the early Neogene coast. Fossils from early pinnipeds such Enaliarctos and the primitive walrus Proneotherium have been found in Lincoln County. [4] [32] Kolponomos newportensis, a bear-like aquatic carnivore with features similar to saber-toothed predators, comes from nearby deposits of similar age. [33] Whales such as Aetiocetus and the primitive mysticete Cophocetus oregonensis appear in Oregon's fossil record in this period. [4] Sirenians and desmostylids have also been found in coastal assemblages. [34] [35] Paleontologists believe that animals in these two groups fed on clams and other mollusks, which is consistent with fossil clam beds found in the Coast Range. [4] The saber-tooth salmon Oncorhynchus rastrosus also swam in Oregon's Neogene rivers. [36] Global cooling in the late Neogene gave way to glaciation in the Quaternary. Oregon's mountain ranges were covered in large ice caps, although the Cordilleran Ice Sheet did not extend into the state. [1] [2] Evidence of ice cap increase and decrease is preserved in a series of glacial lakes, including Glacier Lake. [37] Glacial erratics can be found across the northern half of the state, including sites such as the Erratic Rock State Natural Site. Pluvial lakes are also common across the state. These include Fossil Lake, which is the source of Oregon's largest Pleistocene fossil assemblage. Included in this assemblage are typical Pleistocene megafauna, including Columbian mammoths, dire wolves, Ice Age bison, camels, the ground sloths Mylodon and Megatherium , and the short-faced bear Arctodus (which was previously mistaken for its cousin Arctotherium ). [38] The assemblage also includes over 50 species of waterfowl, including grebes, cormorants, swans, gulls, flamingos, herons, and pelicans. Among the bony fish species found in Fossil Lake's assemblage are several salmon species. [4]
Pleistocene megafauna are found across the northern half of Oregon and include such finds as the Tualatin mastodon, [39] the McMinnville mammoth, [40] and the Woodburn Teratornis. [41] The Willamette Valley Pleistocene Project has reported the discovery of mammoth tracks, attributable to the ichnotaxon Proboscipeda, near the Yamhill River. [42] A spectacular set of 117 mammoth tracks some 43,000 years old at Fossil Lake, near Christmas Valley, reveal a touching drama of wounded mother and concerned yearlings [43] A 9-meter bear trackway, including tracks of the same size and age as Arctodus has been found near Lakeview. [44] [45]
Tectonic activity associated with the Cascadian Subduction Zone continued throughout the Quaternary, leaving evidence of a series of earthquakes and tsunamis in the past 60 thousand years. [46] [47] At the end of the Last Glacial Maximum, collapse of the ice dam surrounding Lake Missoula initiated a series of large-scale floods that inundated much of the state from 19-13 thousand years ago. Around 14 thousand years ago, the Bonneville Flood contributed more floodwaters to many of the same areas. These floods contributed to the modern fertility of the Willamette Valley by transporting soils from the east. [2] Given the timing of these events, it is unlikely that they contributed to the extinction of Pleistocene megafauna such as mammoths and ground sloths in Oregon.
The earliest evidence of human occupation in Oregon comes from human coprolites in Paisley Caves dated to 14,300 years ago. [48] Other early sites include an encampment near Bandon dated to around 10,000 years ago and a pair of sandals from Fort Rock Cave dated to around 9,000 years ago. [2] The margin of error for these dates makes it possible that humans contributed to the extinction of Oregon's Pleistocene megafauna. [49]
Ancient people living near Fossil, Oregon collected fossils as far back as 11,000 years ago and kept them at a dwelling that has since been uncovered by archeologists. Some of the fossils kept there were pierced to be made into jewelry. Five slabs of rock bearing leaf impressions were found neatly stacked in the corner of the site. These and other fossils discovered by Native Americans may have contributed to the development of local myths and lore. Historian Adrienne Mayor cites as an example the Klamath Tribes of the Modoc, who attributed local fossils to water monsters killed by the mythological figure Coyote. [50]
Oregon's first paleontologist was Thomas Condon. Condon began collecting in 1861, when a company of soldiers that arrived in Fort Dalles, where Condon served as the Congregational church pastor. The soldiers brought fossil bones and teeth, including a well-preserved rhinoceros jaw, from the John Day fossil beds. When soldiers were dispatched the following year to Harney Valley, near the fossil beds, Condon went along with them and prospected for fossils. He went fossil collecting again in 1863 and discovered rich fossil deposits north of Picture Gorge in the John Day River valley. [45]
Condon realized that he had stumbled on a find of major scientific importance. Since he himself had no scientific qualifications or references to use in identifying fossils, Condon sent some fossils to Othniel Charles Marsh of Yale University. Marsh replied with a request for Condon to guide an expedition to the area in which he found the fossils. Condon obliged and over the ensuing years a series of fossil hunting expeditions ventured into the John Day fossil beds. A number of Condon's specimens ended up in prestigious museums like the American Museum of Natural History and Smithsonian Institution, with the bulk of his collection stored in the University of Oregon Museum of Natural and Cultural History. [45]
Edward Drinker Cope, whose rivalry with Marsh spurred the "Bone Wars" of the late nineteenth century, also collected fossils in Oregon. [4] His findings from the state are described in his book Vertebrata of the Tertiary Formations of the West. [51]
In the present day, Oregon State University and the University of Oregon both maintain active research programs in paleontology. Oregon State University's Terry Lab, under the supervision of Rebecca Terry, produces research into paleoecology [52] [53] [54] and Quaternary climate change. [55] [56] The University of Oregon's Vertebrate Paleontology Lab, under the supervision of Samantha Hopkins and Edward Davis, focuses on Oregon's extinct mammals. [57] [58] [59] [60] [61] [62] The University of Oregon's paleontology faculty also includes Greg Retallack, who studies fossilized soils. [63] [64] Many of the finds described above were collected, described, and analyzed by researchers in these programs and their predecessors. [4] [45]
John Day Fossil Beds National Monument, managed by the National Park Service, has also been employing paleontologists on staff since the 1980s.The current Paleontology Program Mannager is Dr. Nicholas Famoso. Recent research from the park includes volcano ecology, radiometric dating, gis applications, systematic paleontology, and mammal paleoecology.
The Oregon state legislature declared the species Metasequoia occidentalis to be Oregon's official state fossil in a resolution passed in 2005. [65]
There are several organizations located in Oregon devoted to citizen science initiatives related to paleontology. Among these is the North American Research Group, which was responsible for discovery of the "Mitchell's Monster" plesiosaur and "Bernie" the Jurassic thalattosaurian. [66] Another amateur group is the Willamette Valley Pleistocene Project, which collects from sites in McMinnville, Tualatin, Woodburn, Newberg, and King's Valley.
John Day Fossil Beds National Monument is a U.S. national monument in Wheeler and Grant counties in east-central Oregon. Located within the John Day River basin and managed by the National Park Service, the park is known for its well-preserved layers of fossil plants and mammals that lived in the region between the late Eocene, about 45 million years ago, and the late Miocene, about 5 million years ago. The monument consists of three geographically separate units: Sheep Rock, Painted Hills, and Clarno.
The UW–Madison Geology Museum (UWGM) is a geology and paleontology museum housed in Weeks Hall, in the southwest part of the University of Wisconsin–Madison campus. The museum's main undertakings are exhibits, outreach to the public, and research. It has the second highest attendance of any museum at the University of Wisconsin–Madison, exceeded only by the Chazen Museum of Art. The museum charges no admission.
Haramiyida is a possibly polyphyletic order of mammaliaform cynodonts or mammals of controversial taxonomic affinites. Their teeth, which are by far the most common remains, resemble those of the multituberculates. However, based on Haramiyavia, the jaw is less derived; and at the level of evolution of earlier basal mammals like Morganucodon and Kuehneotherium, with a groove for ear ossicles on the dentary. Some authors have placed them in a clade with Multituberculata dubbed Allotheria within Mammalia. Other studies have disputed this and suggested the Haramiyida were not crown mammals, but were part of an earlier offshoot of mammaliaformes instead. It is also disputed whether the Late Triassic species are closely related to the Jurassic and Cretaceous members belonging to Euharamiyida/Eleutherodontida, as some phylogenetic studies recover the two groups as unrelated, recovering the Triassic haramiyidians as non-mammalian cynodonts, while recovering the Euharamiyida as crown-group mammals closely related to multituberculates.
The Jehol Biota includes all the living organisms – the ecosystem – of northeastern China between 133 and 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation. These deposits are composed of layers of tephra and sediment. It is also believed to have left fossils in the Sinuiju series of North Korea. The ecosystem in the Lower Cretaceous was dominated by wetlands and numerous lakes. Rainfall was seasonal, alternating between semiarid and mesic conditions. The climate was temperate. The Jehol ecosystem was interrupted periodically by ash eruptions from volcanoes to the west. The word "Jehol" is a historical transcription of the former Rehe Province.
Arganodus is an extinct genus of freshwater lungfish that had a wide global distribution throughout much of the Triassic period, with a single species surviving across Gondwana into the Cretaceous. It is the only member of the family Arganodontidae, although it is sometimes placed in the Ceratodontidae or synonymized with the genus Asiatoceratodus.
Ptychoceratodus is an extinct genus of lungfish living from Early Triassic to Middle Jurassic. It was established by Otto Jaekel for one species, transferred from Ceratodus genus. Type species is P. serratus from the Middle Triassic of Switzerland and Germany. Ptychoceratodus had two pairs of massive dental plates, bearing 4-6 acute ridges. Its skull roof was composed from massive, plate-like bones. In the central part of skull roof was localized an unossified fenestra. Most of the Ptychoceratodus findings are isolated dental plates, some associated with jaws. Other parts of skull or postcranial skeleton are relatively rarely found as fossils. The anatomy of skull is the best recognized in P. serratus, whereas less complete cranial material is available also for P. concinuus, P. phillipsi, and P. rectangulus. Although Ptychoceratodus is known exclusively from the Triassic and Jurassic, there were also Cretaceous specimens referred to this genus. However, they are more often regarded as representants of Metaceratodus. Ptychoceratodus is the only member of the family Ptychoceratodontidae. The first named species is P. phillipsi by Louis Agassiz in 1837 as a species of Ceratodus and later moved to Ptychoceratodus genus. Occurrences of Ptychoceratodus come mainly from Europe. However, occurrences from other continents suggest it was dispersed globally during the Triassic. After 2010, the new fossil material behind the Europe was reported from South America, India, and Greenland
Paleontology in North Carolina refers to paleontological research occurring within or conducted by people from the U.S. state of North Carolina. Fossils are common in North Carolina. According to author Rufus Johnson, "almost every major river and creek east of Interstate 95 has exposures where fossils can be found". The fossil record of North Carolina spans from Eocambrian remains that are 600 million years old, to the Pleistocene 10,000 years ago.
Paleontology in Delaware refers to paleontological research occurring within or conducted by people from the U.S. state of Delaware. There are no local rocks of Precambrian, Paleozoic, Triassic, or Jurassic age, so Delaware's fossil record does not begin until the Cretaceous period. As the Early Cretaceous gave way to the Late Cretaceous, Delaware was being gradually submerged by the sea. Local marine life included cephalopods like Belemnitella americana, and marine reptiles. The dwindling local terrestrial environments were home to a variety of plants, dinosaurs, and pterosaurs. Along with New Jersey, Delaware is one of the best sources of Late Cretaceous dinosaur fossils in the eastern United States. Delaware was still mostly covered by sea water through the Cenozoic era. Local marine life included manatees, porpoises, seals, and whales. Delaware was worked over by glaciers during the Ice Age. The Cretaceous belemnite Belemnitella americana is the Delaware state fossil.
Paleontology in South Carolina refers to paleontological research occurring within or conducted by people from the U.S. state of South Carolina. Evidence suggests that at least part of South Carolina was covered by a warm, shallow sea and inhabited by trilobites during the Cambrian period. Other than this, little is known about the earliest prehistory of South Carolina because the Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, and Jurassic, are missing from the state's local rock record. The earliest fossils of South Carolina date back to the Cretaceous, when the state was partially covered by seawater. Contemporary fossils include marine invertebrates and the remains of dinosaur carcasses that washed out to sea. On land, a wide variety of trees grew. Sea levels rose and fell throughout the ensuing Cenozoic era. Local marine life included invertebrates, fish, sharks, whales. The first scientifically accurate identification of vertebrate fossils in North America occurred in South Carolina. In 1725, African slaves digging in a swamp uncovered mammoth teeth, which they recognized as originating from an elephant-like animal.
Paleontology in Louisiana refers to paleontological research occurring within or conducted by people from the U.S. state of Louisiana. Outcrops of fossil-bearing sediments and sedimentary rocks within Louisiana are quite rare. In part, this is because Louisiana’s semi-humid climate results in the rapid weathering and erosion of any exposures and the growth of thick vegetation that conceal any fossil-bearing strata. In addition, Holocene alluvial sediments left behind by rivers like the Mississippi, Red, and Ouachita, as well as marsh deposits, cover about 55% of Louisiana and deeply bury local fossiliferous strata.
Paleontology in Oklahoma refers to paleontological research occurring within or conducted by people from the U.S. state of Oklahoma. Oklahoma has a rich fossil record spanning all three eras of the Phanerozoic Eon. Oklahoma is the best source of Pennsylvanian fossils in the United States due to having an exceptionally complete geologic record of the epoch. From the Cambrian to the Devonian, all of Oklahoma was covered by a sea that would come to be home to creatures like brachiopods, bryozoans, graptolites and trilobites. During the Carboniferous, an expanse of coastal deltaic swamps formed in areas of the state where early tetrapods would leave behind footprints that would later fossilize. The sea withdrew altogether during the Permian period. Oklahoma was home a variety of insects as well as early amphibians and reptiles. Oklahoma stayed dry for most of the Mesozoic. During the Late Triassic, carnivorous dinosaurs left behind footprints that would later fossilize. During the Cretaceous, however, the state was mostly covered by the Western Interior Seaway, which was home to huge ammonites and other marine invertebrates. During the Cenozoic, Oklahoma became home to creatures like bison, camels, creodonts, and horses. During the Ice Age, the state was home to mammoths and mastodons. Local Native Americans are known to have used fossils for medicinal purposes. The Jurassic dinosaur Saurophaganax maximus is the Oklahoma state fossil.
Paleontology in Texas refers to paleontological research occurring within or conducted by people from the U.S. state of Texas. Author Marian Murray has said that "Texas is as big for fossils as it is for everything else." Some of the most important fossil finds in United States history have come from Texas. Fossils can be found throughout most of the state. The fossil record of Texas spans almost the entire geologic column from Precambrian to Pleistocene. Shark teeth are probably the state's most common fossil. During the early Paleozoic era Texas was covered by a sea that would later be home to creatures like brachiopods, cephalopods, graptolites, and trilobites. Little is known about the state's Devonian and early Carboniferous life. Evidence indicates that during the late Carboniferous the state was home to marine life, land plants and early reptiles. During the Permian, the seas largely shrank away, but nevertheless coral reefs formed in the state. The rest of Texas was a coastal plain inhabited by early relatives of mammals like Dimetrodon and Edaphosaurus. During the Triassic, a great river system formed in the state that was inhabited by crocodile-like phytosaurs. Little is known about Jurassic Texas, but there are fossil aquatic invertebrates of this age like ammonites in the state. During the Early Cretaceous local large sauropods and theropods left a great abundance of footprints. Later in the Cretaceous, the state was covered by the Western Interior Seaway and home to creatures like mosasaurs, plesiosaurs, and few icthyosaurs. Early Cenozoic Texas still contained areas covered in seawater where invertebrates and sharks lived. On land the state would come to be home to creatures like glyptodonts, mammoths, mastodons, saber-toothed cats, giant ground sloths, titanotheres, uintatheres, and dire wolves. Archaeological evidence suggests that local Native Americans knew about local fossils. Formally trained scientists were already investigating the state's fossils by the late 1800s. In 1938, a major dinosaur footprint find occurred near Glen Rose. Pleurocoelus was the Texas state dinosaur from 1997 to 2009, when it was replaced by Paluxysaurus jonesi after the Texan fossils once referred to the former species were reclassified to a new genus.
Paleontology in Colorado refers to paleontological research occurring within or conducted by people from the U.S. state of Colorado. The geologic column of Colorado spans about one third of Earth's history. Fossils can be found almost everywhere in the state but are not evenly distributed among all the ages of the state's rocks. During the early Paleozoic, Colorado was covered by a warm shallow sea that would come to be home to creatures like brachiopods, conodonts, ostracoderms, sharks and trilobites. This sea withdrew from the state between the Silurian and early Devonian leaving a gap in the local rock record. It returned during the Carboniferous. Areas of the state not submerged were richly vegetated and inhabited by amphibians that left behind footprints that would later fossilize. During the Permian, the sea withdrew and alluvial fans and sand dunes spread across the state. Many trace fossils are known from these deposits.
Paleontology in New Mexico refers to paleontological research occurring within or conducted by people from the U.S. state of New Mexico. The fossil record of New Mexico is exceptionally complete and spans almost the entire stratigraphic column. More than 3,300 different kinds of fossil organisms have been found in the state. Of these more than 700 of these were new to science and more than 100 of those were type species for new genera. During the early Paleozoic, southern and western New Mexico were submerged by a warm shallow sea that would come to be home to creatures including brachiopods, bryozoans, cartilaginous fishes, corals, graptolites, nautiloids, placoderms, and trilobites. During the Ordovician the state was home to algal reefs up to 300 feet high. During the Carboniferous, a richly vegetated island chain emerged from the local sea. Coral reefs formed in the state's seas while terrestrial regions of the state dried and were home to sand dunes. Local wildlife included Edaphosaurus, Ophiacodon, and Sphenacodon.
Paleontology in Idaho refers to paleontological research occurring within or conducted by people from the U.S. state of Idaho. The fossil record of Idaho spans much of the geologic column from the Precambrian onward. During the Precambrian, bacteria formed stromatolites while worms left behind trace fossils. The state was mostly covered by a shallow sea during the majority of the Paleozoic era. This sea became home to creatures like brachiopods, corals and trilobites. Idaho continued to be a largely marine environment through the Triassic and Jurassic periods of the Mesozoic era, when brachiopods, bryozoans, corals, ichthyosaurs and sharks inhabited the local waters. The eastern part of the state was dry land during the ensuing Cretaceous period when dinosaurs roamed the area and trees grew which would later form petrified wood.
Paleontology in Nevada refers to paleontological research occurring within or conducted by people from the U.S. state of Nevada. Nevada has a rich fossil record of plants and animal life spanning the past 650 million years of time. The earliest fossils from the state are from Esmeralda County, and are Late Proterozoic in age and represent stromatolite reefs of cyanobacteria, amongst these reefs were some of the oldest known shells in the fossil record, the Cloudina-fauna. Much of the Proterozoic and Paleozoic fossil story of Nevada is that of a warm, shallow, tropical sea, with a few exceptions towards the Late Paleozoic. As such, many fossils across the state are those of marine animals, such as trilobites, brachiopods, bryozoans, honeycomb corals, archaeocyaths, and horn corals.
Paleontology in Alaska refers to paleontological research occurring within or conducted by people from the U.S. state of Alaska. During the Late Precambrian, Alaska was covered by a shallow sea that was home to stromatolite-forming bacteria. Alaska remained submerged into the Paleozoic era and the sea came to be home to creatures including ammonites, brachiopods, and reef-forming corals. An island chain formed in the eastern part of the state. Alaska remained covered in seawater during the Triassic and Jurassic. Local wildlife included ammonites, belemnites, bony fish and ichthyosaurs. Alaska was a more terrestrial environment during the Cretaceous, with a rich flora and dinosaur fauna.
The geological history of North America comprises the history of geological occurrences and emergence of life in North America during the interval of time spanning from the formation of the Earth through to the emergence of humanity and the start of prehistory. At the start of the Paleozoic Era, what is now "North" America was actually in the Southern Hemisphere. Marine life flourished in the country's many seas, although terrestrial life had not yet evolved. During the latter part of the Paleozoic, seas were largely replaced by swamps home to amphibians and early reptiles. When the continents had assembled into Pangaea, drier conditions prevailed. The evolutionary precursors to mammals dominated the country until a mass extinction event ended their reign.
The La Meseta Formation is a sedimentary sequence deposited during the Eocene on Seymour Island off the coast of the Antarctic Peninsula. It is noted for its fossils, which include both marine organisms and the only terrestrial vertebrate fossils from the Cenozoic of Antarctica.
The Hudspeth Formation is a Cretaceous sedimentary rock formation, found in Oregon of the United States of America. The formation dates to the Albian age of the Early Cretaceous period. During the Albian much of this formation was submerged beneath shallow seas resulting in the preservation of many marine fossils. Pterosaur, dinosaur and marine fossils have been recovered from the formation. It is intertongued with the Gable Creek Formation.