In my original critique of this article, I noted a need for two major revisions. One major revision will be the addition of recent research findings. The other major revision will be a reorganization of information in the article. These two areas of improvement are related. Research programs at the University of Oregon and Oregon State University have provided a wealth of new information about Oregon's prehistory. That additional information, once incorporated into the article, will permit for a higher-resolution division and organization of topics.

My original critique included a suggestion that the current article's division between "Prehistory" and "History" sections is artificial and theoretically unsound; however, that division follows from the Paleontology portal's style guide and so must remain in place. Instead of making that change, I now intend to introduce into the "Prehistory" section additional sub-sections that focus on Oregon's paleoenvironment (including paleogeography and paleoclimatology), paleobotany, paleozoology, and paleoichnology. Each of these sections will be divided into the geological eras for which we have information from Oregon. In the "History" section, I will expand upon the "Scientific Research" section by specifying particular research projects undertaken at OSU and U of O. I will also add a section on amateur fossil collecting in Oregon. I have already posted references for this material in my original critique and in my minor revision to the article.

Paleontology in Oregon (revision draft)

Paleontology in Oregon refers to

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

Prehistory

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].

Paleozoic Era

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 Ma, during the Devonian period of the Paleozoic era. These deposits include condonts 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

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].

Mesozoic Era

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

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^[2][3]. 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

There is no geological record in Oregon of the K-Pg boundary or of the event that ended the Mesozoic era^[2][3].

Cenozoic Era

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^[15]. Invertebrate foramenifera from the Paleogene have been reported from sediments in Coos County, but their identity remains disputed^[16][17][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

dogfish, horn sharks, comb-toothed sharks, makos, tiger sharks, white sharks, and an archaic basking shark^[19]. 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^[20][21]. The state's only known fossil egg was found in associated rock formations.

In the transition from the

Metasequoia occidentalis, a conifer closely related to modern redwoods, flourished across the state during this time[2]^[4]. The Oregon state legislature declared the species to be Oregon's official state fossil in a resolution passed in 2005^[29].

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][30]. Kolponomos newportensis, a bear-like aquatic carnivore with features similar to saber-toothed predators, comes from nearby deposits of similar age^[31]. 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^[32][33]. 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^[34].

Global cooling in the

Pleistocene megafauna are found across the northern half of Oregon and include such well-publicized 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]. Pleistocene whale fossils are common along Oregon's coast^[4].

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

The earliest evidence of

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^[46].

Scientific research

Professional work

Oregon's first paleontologist was

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. Fossils uncovered during these excavations ended up in a wide variety of prestigious museums like the American Museum of Natural History and Smithsonian Institution^[38].

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^[47].

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^[48][49][50] and Quaternary climate change.^[51][52][52] The University of Oregon's Vertebrate Paleontology Lab, under the supervision of Samantha Hopkins and Edward Davis, focuses on Oregon's extinct mammals.^{[53][54][55][56][57][58]} The University of Oregon's paleontology faculty also includes Greg Retallack, who studies fossilized soils.^[59][60] Many of the finds described above were collected, described, and analyzed by researchers in these programs and their predecessors^[4][38].

Amateur work

There are several organizations located in Oregon devoted to

• Thomas Condon
• Othniel Charles Marsh
• Edward Drinker Cope

Notable Sites

Fossil localities

• Astoria Formation
• Blue Mountains
• Coyote Butte Formation
• Fossil Lake
• John Day Fossil Beds National Monument
• Keasey Formation
• Nye Formation
• Pittsburg Bluff Formation
• Wallowa Mountains

Protected areas

• John Day Fossil Beds National Monument

Natural history museums

• University of Oregon Museum of Natural and Cultural History, Eugene
• Thomas Condon Paleontology Center, John Day Fossil Beds National Monument

Feedback

Hello DinosaurPhilosophy,

Here I will attempt to review your critique and plan. Combining Protected areas and Natural history museums into subtopics of important sights makes the article more cohesive. Adding notable people with a biography of each does provide helpful background. It looks as though you plan to break Prehistory into subtopics? Breaking up that large section would definitely provide organization and make the article more readable. Updating the lead section for adjustments would of course be needed. ~~~~ WoodPig (5/12/17)