The National Park Service
John Day Fossil Beds
Interactive Flash Feature
Travel back into the distant past in North America, to the wilds of volcanic Oregon. This is a place where strange
and inconceivable plants and animals existed, and were captured by fossils forever, by sudden, huge and rapid natural disasters.
Learn about them and how paleontologists do their work.
The Present Unlocks the Past.
40,000,000 years ago. The area that would become John Day Fossil Beds. Mud flows. Ashfalls and ignimbrites.
Lava flows. Yet, life was reborn: Again and again.
- A Horse is a Horse..Or is It? The Evolution of a Horse In Prehistoric Oregon
- Where Did They Come From? Modern Skulls and their Fossil Ancestors
- Uncovering the Past Tools and Tales of the Working Paleontologist
- Behind the Glass Tour of the Paleontologist’s Lab
- Slideshow
- The Painted Hills wear their geological history in vivid bands of color. These mounds of ancient volcanic ash over 1000 feet high are striking
in that only the most hardy grasses can flourish on their shifting and chemically incompatible soils. The high clay content and rapid erosion during
infrequent storms prevents plants from becoming established in the badlands areas.
- A lone bald eagle perches on a bluff above the John Day River. The proud birds, once endangered, have bounced back. Major credit is due to the
federal Endangered Species Act for eagle recovery. Bald eagles were listed as a threatened species in Oregon under the ESA in 1978. The act protects
not just the eagles, but also their habitat. The eagles' success stems as well from educational outreach programs and conservation organizations.
- Akin to the surface of the mysterious "Red Planet", or Mars, the color-splashed hummocks and hills are the eroded remnants of the lower
John Day Formation. The weathering of volcanic ash under varying climatic regimes resulted in vividly-hued rock layers of red, pink, bronze, tan,
and black.
- Shown here in this picture of Round Up Flat, the Turtle Cove Strata, colored pastel bluish-green by minerals, are volcanic ash deposits
transformed into claystone by eons of erosion. These claystones yield a rich variety of vertebrate fossils.
- Some of the hills in the Painted Hills seem like sand dunes, but up close their more rough texture is revealed.
- A bald eagle soars majestically overhead.
- The beautiful colors of the claystone at John Day read like a 'who's who' of Oligocene and Miocene fossil strata.
- Mountainous forms thrust up into the sky. Wide spread volcanic lava flows separate the John Day layers from the younger Mascall and
rattlesnake formations. When these lava flows cooled they formed large columns of basalt that can be seen for miles around the John Day Basin.
- Odocoileus hemionus, or Mule Deer are usually found in either rocky, brushy areas or open meadows. Occasionally they are found in scattered
coniferous groves in open desert country.
- This view of the Painted Hills shows the multiple layers. The gray layers are mudstone, siltstone, and shale formed from sediments deposited
on an ancient river floodplain. The black layers are manganese nodules or manganese stains. The red layers are ancient soil profiles (laterites)
that formed on floodplain deposits. Surface weathering relatively quickly breaks down these rocks into a clay-rich surface coating that easily
erodes during summer flashfloods and/or winter storms.
- Strikingly rich red colors conjure an otherworldly feel at the Painted Hills.
- The John Day River runs through the center of the Sheep Rock Unit at the park. This is a rural area, with few human inhabitants.
- From the parking lot at the Painted Hills, the visitor is treated to awes-inspiring views.
- A closeup of a cross section of the main Painted Hills, showing the brilliant colors of the different desposits.
The Evolution of a Horse In Prehistoric Oregon
Despite the size and diversity of the horse family tree over the last 50 million years, the only genus of horse that exists today is Equus,
which includes all domesticated horses, asses, and zebras.
Nonetheless an outstanding array of prehistoric horses existed.
Although a dizzying variety of different horses evolved in North America, they all died out. Equus, the horse as we know it, the import
cultural icon and staple of the American Western imagery is actually an “import model:” it evolved in Asia and was brought to the New World by
explorers and settlers.
In the late 19th century, the discovery of horse fossil at John Day and Hagerman Fossil Beds rocked the world by providing very strong evidence
for the theory of evolution.
- Orohippus – Appeared 54 million years ago. The name means ‘Mountain Horse.”
- Miohippus – Appeared 32 million years ago. The name means ‘Little Horse.”
- Parahippus – Appeared 24 - 17 million years ago. The name means “Side Horse.”
- Merychippus – Appeared 17 - 11 million years ago. The name means “Ruminant Horse.”
- Archaeohippus – Appeared 21 - 13 million years ago. The name means “Ancient Horse.”
- Pliohippus – Appeared 12 - 6 million years ago. The name means “More Horse.”
- Equus – Appeared from 5 million years ago to present. Equus means “Horse.”
This little horse appears in the fossil record about 54 million years ago, 2 million years after Hyracotherium,
the first of all the horses, but the two genera coexisted during the Eocene in places like Wyoming.
Fossils of Orohippus have been
found in Wyoming and Oregon, dating from about 52-45 million years ago, during the Clarno Nut Beds.
A sheep sized browser of a horse, gave rise to a great diversity of horses. Many species of Miohippus
coexisted and the horse family tree became larger and more branchy after the success of Miohippus.
Fossils of Miohippus are found in the Great
Plains, the Western US and a few places in Florida. Species in this genus lived from about 32-25 million years ago during the Turtle Cove.
Slow
Increase in Species
Several species co-existed within the genus Miohippus. As changes accumulate, sub-populations may separate and co-exist.
Like branches growing off the main trunk of a tree, these populations become separate species when enough change occurs that they can no longer interbreed.
This is known as cladogenesis.
Species of Parahippus have teeth of medium height good for eating a variety of grasses and leaves. They have three toes, but the side toes are
greatly reduced. These horses are thought to be a link between forest-dwelling horses and grassland dwelling razers.
Fossils of Parahippus
are found in Oregon the Great Plains and Florida. Species in this genus lived from 24 -17 million years ago, during the Haystack Valley Assemblage.
Thought of as the first known grazing horse, Merychippus possessed the high crowned or 'hypsodont'
teeth needed for eating a diet of mostly grasses. Though this genera was similar to a modern horse having a long face, and long legs that would allow it to
out run predators, Merychippus still retained the 3 toes inherent in older horses.
Fossils of Merychippus are found throughout the
United States. Species in this genus lived from 17 - 11 million years ago, in Oregon, during the Mascall Assemblage.
Was a small browsing horse living during a time when horses in general were becoming larger and surviving on grasses. Archaeohippus's small size and
low crowned teeth enabled it to exploit the pockets of forest that remained as grasslands began to take over.
Archaeohippus fossils are found
in Nebraska, Oregon, California, and Florida. Species in this genus lived from 21 - 13 million years ago.
Was a "single-toed" horse, a close ancestor to the modern horse. These horses were adapted for out-running predators
and eating a diet of primarily grasses.
Fossils of Pliohippus are found in Oregon, Colorado, the Great Plains of the US (Nebraska and the
Dakotas) and Canada. Species in this genus lived from 12 - 6 million years ago.
Despite the size and diversity of the horse family tree over the last 50 million years, the only genus of horse that exists on earth today is
Equus, which includes all domesticated horses, asses, and zebras. These horses are considered grazers because of their high
crowned 'hypsodont' teeth. They also only have a single toe on each foot.
Horses were domesticated about 6,000 years ago, and humans have depended
on them for travel, warfare, farming and sport ever since.
Species of Equus lived from 5 million years ago until the present. Fossils of
Equus are found on every continent except Australia and Antarctica.
Modern Skulls and their Fossil Ancestors
I am an alligator. Sometimes people get alligators and crocodiles confused, but we're a little bit different. We are both one of the two remaining archosaurs
(same group as dinosaurs) still in existence; the other one is birds.
Pristichampsus sp.
Fossil jaw, from a crocodile has sharp, serrated teeth.
Similarities/Differences
- Have changed very little in the last 225 million years.
- Are one of the two remaining archosaurs (same group as dinosaurs) still in existence (the other one is birds).
- Alligators and crocodiles are from different families.
- In the past, some varieties were fully terrestrial.
Climate of the Day - Back when Pristichampsus was around, the climate in Oregon was warm and near tropical, very different from the modern arid
landscape of eastern Oregon, but a perfect setting for a crocodilian.
Environment
- Pristichampsus fossils were found in rocks from the Clarno Formation 54 million years ago.
- Pristichampsus fossils were found in parts of the world not inhabited by any modern crocodilians.
- Pristichampsus may have been better adapted to living on land than other crocodilians.
- Pristichampsus had sharp, serrated teeth.
- Like modern crocodilians, Pristichampsus probably preyed on mammals.
Useful Links
I am a 'Collared Peccary' or 'Javelina.' Today we live in areas from the southwestern United States down through central Argentina. I am descended from a
line of ancestors that has lived in North America for about 35 million years. Peccaries are not pigs!
Similarities/Differences - Today male and female peccaries look pretty much alike. Several million years ago though, the males and females
could be told apart more easily by long canines and bony bumps on the skulls of males.
Climate of the Day - This peccary lived during the Rattlesnake Assemblage, about 8 million years ago, when this area was covered with grass and low
brushy plants much like today. Further back peccaries lived happily in the forests of the Oligocene as well.
Environment
- Peccaries are the closest living relatives of pigs but they are different enough that scientists put them in their own family the Tayassuidae.
- Edward Abby had this to say about the subject: [Peccaries are] Not a true pig exactly, according to zoologists, but a good approximation, a close
relation. Close enough for me and for the Javelina. Commonly defined as “wild pig-like animal” it’s the best kind of pig. Though that definition come to
think of it, is a shade broad. Some of my best friends qualify as wild pig-like animals without half trying.
- They live most often in small bands and eat a variety of nuts, berries, roots, cacti, fungus, and occasionally consume small animals.
- The word 'javelina' come from the Spanish word for javelin or spear and refers to their sharp tusks.
- Their tusks, speed, agility, and strong family ties make them a match for most predators.
- There is even some evidence that they are immune to rattlesnake venom.
Useful Links
Displayed is a skull fossil from the modern domesticated horse Equus caballus. 10,000 years ago my genus existed all over the world. After that we went
extinct for a time in the new world. Now all domestic horses are descended from ancestors from Asia.
Similarities/Differences
- Miohippus was a three toed horse.
- Modern horses like Equus walk around on a single toe on each foot.
- Modern horses are considered to be grazers (grass eaters).
- Miohippus was a browser (ate leaves and shrubs).
- Miohippus was one of many genera of horses that existed at one time in Oregon.
- Equus is the only remaining genera of horses that exists in the world.
- Miohippus was a much smaller horse than Equus, about the size of a sheep.
Climate of the Day - Back when Miohippus was around the now near desert environment of eastern Oregon was dominated by hard wood deciduous
forests. The climate was seasonal, with about 50 inches of rainfall per year. Hardwood forests were sometimes flooded with ash and pumice from nearby
volcanoes. Grasses were just beginning to appear, but they were not yet a major part of the landscape.
Environment
- Fossils of Miohippus date back to the Oligocene, 32-25 million years ago.
- Fossils of Miohippus are found at many Oligocene localities, in the Great Plains, the Western US and a few places in Florida.
- Fossils of Miohippus are found in the Turtle Cove Assemblage at the John Day Fossil Beds.
Useful Links
I'm a Cougar, Felis concolor. You may know me by many names, puma, cougar, or mountain lion. My ancestor was not nimravid like Eusmilus,
it was a 'true cat.' True cats showed up in North America about 15 million years ago. Nimravids are very similar to true cats but not the same.
Similarities/Differences
- True cats (Felids), which include the cougar, Felis concolor, and Nimravids are only distantly related. Even though their body
structure is very similar, they evolved separately.
- Nimravids were primarily North American, filling the niche that would later be occupied by felids when they came to North America from the old world.
- Like the felid family, the nimravid family contained a variety of species both large and small.
- Nimravids went extinct during the Miocene and have no living descendents, whereas felids are with us today as lions, tigers, bobcats and house cats.
Climate of the Day - Eusmilus lived during the Turtle Cove Assemblage, 29 million years ago, when hardwood forests dominated the
landscape and the climate was temperate and humid.
Environment
- Sometimes called the "toy sabertooth," Eusmilus was one of the smallest nimravids, about the size of a modern bob cat.
- It possessed long saber teeth and a lower jaw that could open very wide. Also the lower jaw was shaped like an "L" in front to help protect
the upper teeth when the mouth was closed. Their long teeth would have acted as excellent killing tools, but may have made chewing more
difficult.
- Like all nimravids, Eusmilus could be considered a hypercarnivore, dining almost entirely on the fresh meat of small oreodonts,
(hoofed herbivores that are also extinct) mouse deer and three toed horses like Miohippus.
Useful Links
We bears used to be MUCH bigger, but even though we're smaller now, we're just as interesting - and fierce!
Similarities/Differences - Sometimes called a "short faced bear" Indarctos was gigantic. Standing on its hind legs it would
have been 16 feet tall, able to look into a second story window. The North American Black Bear (Ursus americanus) are only 4-7 feet
tall and even the largest of the modern bears, the Polar Bear, (Ursus maritimus) only stands about 8 to 10 feet tall.
Climate of the Day - Back when Indarctos was around, the climate in Oregon had cooled dramatically, grasslands were wide spread
and rainfall had decreased to 15 inches per year.
Environment
- The earliest Indarctos fossils were found in Eurasia, and Indarctos was thought to be exclusively Old World
until fossils of Indarctos Oregonensis were found in the Rattlesnake Assemblage at John Day Fossil Beds.
- Indarctos Oregonensis was most likely the only species of Indarctos to have lived in North America and
its discovery added to the evidence that animals were migrating into North America from the Old World via the Bering Land Bridge.
Useful Links
Displayed is the fossil of an African Lion! Panthera leo is my scientific name, but you can just call me Leo. I'm a true cat, but the fossil you see
below IS NOT!
Similarities/Differences
- True cats (felids) and nimravids are only distantly related. Even though their body structure is very similar, they evolved separately.
- Nimravids were primarily North American, filling the niche that would later be occupied by felids when they came to North America from the old world.
- Like the felid family, the nimravid family contained a variety of species both large and small.
- Both felids and nimravids displayed saber teeth in some species.
- Nimravids lack certain ear bones (the auditory bulla) which is found on felid skulls and is evidence that they share different ancestry.
- Nimravids went extinct during the Miocene and have no living descendents, whereas felids are with us today as lions, tigers, bobcats and house cats.
Climate of the Day - Pogonodon lived during the Turtle Cove Assemblage, 29 million years ago, when hardwood forests dominated the landscape
and the climate was more seasonal.
Environment
- Pogonodon was one of the larger nimravids, about the size of a modern lion.
- Pogonodon had a strong, robust upper body which may have been used for tackling prey.
- Pogonodon is sometimes called the "John Day Tiger."
- Pogonodon might have hunted oreodonts (hoofed herbivores that are also extinct), rhinos, three toed horses, or the occasional mouse deer.
Useful Links
I'm a wolf, Canis lupis. But my ancestor was Mesocyon, the 'short-faced dog.' He was a scrappy character: good at climbing trees!
We were different, but I really admire my ancestral short faced dog.
Similarities/Differences
- Mesocyon was a medium-sized dog that may have looked more like a cross between a weasel and a fox.
- Unlike modern dogs (wolves, coyotes, and your pet dog) short faced dogs like Mesocyon, possessed unfused wrist bones allowing them to
climb in trees, and swipe at their prey, but these dogs were probably not very fast runners.
- Short faced dogs also had stronger, more robust jaws and teeth. These dogs would have been specialized for crushing the bones of their prey
to get to the nutrient rich marrow inside.
Climate of the Day - Mesocyon lived during the Turtle Cove Assemblage, 29 million years ago, when hardwood forests dominated the landscape
and the climate was temperate and humid.
Environment - The history of dogs extends back to 40 million years ago, when a variety of dog-like predators bearing distinctive pairs of shearing
teeth evolved in North America. Relatives of Mesocyon would eventually become members of the canid (true dogs) family.
Useful Links
I am a turtle. I know, pretty impressive. I am descended from a long line of prehistoric turtles. I am actually a snapping turtle. Only one
snapping turtle has ever been discovered at John Day, but there were other kinds of turtles and tortoises.
Similarities/Differences
- Though both turtles and tortoises are in the same order, Testudines, they tend to have different habitat needs and a different diet.
- Turtles and tortoises have changed physically very little, but like many other animals they have family lineages that have died out,
while others have survived to become our modern varieties.
- The modern skull is from a carnivorous turtle, whereas Stylemys would have been strictly herbivorous. Notice the sharp beak on the
snapping turtle, good for killing prey.
- Stylemys is more closly related to the modern gopher tortoises than to a snapping turtle.
- Stylemys' forelimbs are not adapted for digging like other tortoises, they lived on land but did not dig burrows.
Climate of the Day - Stylemys lived during the Turtle Cove Assemblage, 29 million years ago, when hardwood forests dominated the landscape
and the climate was temperate and humid.
Environment
- Stylemys may have lived exclusivly in North America, but studies of european and asian varities of fossil tortoises could turn out to be
either Stylemys or ealier relatives.
- Stylemys do not develop the os transiliens, a special, sesamoid bone in the skull of gopher tortoises that increases chewing
efficiency, making it easier to eat tougher, more drought tolerant plants.
- Stylemys is a member of the family Testudinidae that are commonly known as tortoises. Members of this group typically have thick
shells that are highly domed, elephantine limbs, and are strictly terrestrial.
- Very recently, a snapping turtle fossil specimen was actually discovered at John Day!
Useful Links
We're large, pig-like animals, with a short, prehensile trunk. We're
indigenous to most of the rainforested areas of S. America and parts of S.E. Asia. Most of us are threatened or endangered.
Similarities/Differences
- The earliest tapirs were much smaller than modern tapirs.
- Tapirs overall have changed very little.
- The fossil record shows that tapirs at one time were very widespread whereas today tapirs only exist in Asia and South America.
Climate of the Day - Back when Protapirus was around, Eastern Oregon had a near tropical climate and there was a variety plants for a tapir to
feed on.
Environment
- Protapirus lived during the Eocene in North America.
- Protapirus was a browser.
- Protapirus was most likely nocturnal, like the tapirs that live today.
Useful Links
We rhinos today are considered to be highly endangered, but in the past, we roamed the world!
Similarities/Differences
- Many ancient rhinos were much smaller than any of the modern living rhinos, Telataceras was about the size of a modern sheep.
- Not all rhinos had horns, and those that did sometimes had horns on either side of their nose. Telataceras did not have horns,
whereas the sumatran rhino and other modern rhinos have two marching down the front of their skull.
- Rhinos today are considered to be highly endangered, they only exist in very small numbers in Asia and Africa, but in the past rhinos existed
in many places in North America, as well as in Asia and Africa.
Climate of the Day - Back when Telataceras was around, the climate in Oregon was warm and humid, unlike the arid desert environment
of eastern Oregon today.
Environment
- Telataceras fossils were found in rocks from the Hancock Mammal Quarry, in the Clarno Formation, about 40 million years old.
- Telataceras is considered the first true rhino to exist on earth.
- Telataceras, like all rhinos, was a plant eater.
Useful Links
Tools and Tales of the Working Paleontologist
- The Thrill of Discovery
Paleontologists love to discover fossils. Each new find is a another clue to unraveling the mystery of life in Earth's distant past. But finding
a fossil in the field is just the first step. To have scientific value, each specimem must be properly collected and documented. Its exact location
must be recorded, along with its condition, position and stratigraphic level - the specific position in a layer of rock. Only then can the fossil be
carefully removed from the field and taken to the lab for further preparation and study.
- Sometimes the fossil material found is very fragile. But we can protect the exposed bone by covering it with wet strips of paper and
then "plaster jacketing" it with layers of pieces of sack cloth dipped in plaster.
- While published maps and/or GPS data are extremely important, a collector's field notes, sketches and photographs are crucial for
providing details that other media cannot supply.
- In surveying, the Jacob's staff is a single straight rod, pointed and iron-shod at the bottom, for penetrating the ground. It is used,
instead of a tripod, for supporting a compass.
- Global Positioning System (GPS): A worldwide radio-navigation system that was developed by the US. Department of Defense. In addition to
military purposes it is widely used in marine, terrestrial navigation and location based services.
- Compasses are an invaluable tool for locating and relocating a fossil site. Together with a GPS, they ensure that a find won't be lost.
- Digital cameras are exceptionally handy because of their ability to quickly document a location, specimen, or procedure.
- Aerial photography can be analyzed to find areas that might be rich in fossils!
- All the gear has to be carried in a trusty backpack. And for nourishment, there is always that ready to eat, delicious trail food:
vienna sausages.
- Life After Discovery
Once a fossil has been discovered, there are a few different things that can happen.
- Prospect a fossil
Once a fossil has been discovered, and its geographical location has been recorded, the hard work of excavation begins.
Using rock hammers, pick axes, brooms and brushes, this work is often done in extremely hot weather and steep terrain.
- Jacket a fossil
Using plaster bandages and burlap or tissue, the fossil is protected inside a "jacket" for transport back to the lab.
- Get it to the lab
Large specimens may take several days to completely remove from the field. Helicopters are sometimes used to bring large specimens closer
to a paleotologist's vehicle.
Inside the controlled environment of the lab, fossils are slowly revealed as the rock surrounding them is carefully scraped away.
- Museum collection: the inside scoop - a slide show
- Welcome to the Museum collections. Much like a library, the collections in a museum need to be organized so that fossils are easy to find,
and are kept safe so that the fossils don’t get damaged.
- A drawer may contain many or very few examples of the same kind of animal. The specimens in the drawer on the left are all teeth from
extinct pronghorn antelope. The drawer on the right holds two tortoise shells.
- This drawer holds two nimravid specimens. One is the skull of a Pogonodon. The other is the skull and some limb bones of a Nimravus.
They are both held safely in specimen trays lined with special foam that is chemically inert.
- Plant fossils are arranged by locality rather than species of plant. This makes it easy to study the ecological relationships of an entire
forest.
- This drawer holds a fossil of a sycamore fruit and leaf, two unidentified leaves, and a twig from a conifer tree. A real diversity. Why
were these plants growing together?
- Animal fossils are sometimes kept so that creatures related to one another are in the same drawer. These are all fossils of relatives of
the Mountain Beaver, or Sewellel, of the Pacific Northwest.
- Not all important fossils are large or rare. Fossils of small animals can tell a scientist a lot about a specific place and time.
- Not all important fossils are unique. On the left are individual teeth of Mountain Beavers of several different species and ages. There is
nly one species of Mountain Beaver left today. On the right are the lower and upper jaws of a single Mountain Beaver. Sometimes it is hard to
find fossils this complete of such tiny creatures.
- Complex fossils need to stored carefully. This mixed up Oreodont skeleton is kept in a padded plaster shell with the best points to lift
the fossil out of the shell indicated.
- The cheek bone of this nimravid (shaped like a backwards C) is very delicate. It has a little ramp of foam to support the raised end.
- Sometimes surprising visual aids make their way into collections. These are the bones of the arm of a peccary.
- By grouping fossils, like these elephant bones, in different ways and keeping them safe collections become critical resources for answering
all sorts of important questions.
- Which fossils in a collection are best suited to go on display in a gallery?
- The Thomas Condon Gallery features fossils from the John Day Basin.
- This camel skull is very complete, attractive, and scientifically important. This is a great selection for display.
- A brass stand with acid felt padding is constructed with the intention that the stand will fade into the background.
- The fit is check repeatedly and adjusted to make sure the specimen is securely held.
- Presto! With the proper lighting the skull seems to float in space.
- Specimens such as these snails can be attractively clustered together on the same stand.
- Out on the gallery rock-work the greenish turtle cove matrix remaining on this entelodont jaw make it look as if the specimen lifted
itself out of the rock.
- By grouping related animals the diversity of the group can be highlighted. Here is a sample of the oreodonts that lived together 25
million years ago.
- From Further away the same display reveals the diversity of the same fauna; camels, peccaries, nimravids, termites, turtles,
rhinoceroses, and entelodonts are included.
- In the Clarno cases a startling variety of plants are arranged at different heights in a busy yet cohesive display.
- Drawers in the rock-work allow visitors to the gallery to get up close and personal with the ghostly fossils of ancient leaves from the
Bridge Creek assemblage.
- Some of the most interesting fossil are of small creatures. In the Turtle Cove Assemblage visitors can inspect the tiny fossils of
rodents, birds, insectivores, primates, and limbless lizards. Some are displayed under magnifying domes for an even more intimate view.
Tour of the Paleontologist’s Lab
After being removed from the field, fossils are taken to a lab where they can be made available for study. Each fossil goes through stages before
it can be handled by researchers: stabilization, preparation, and sometimes casting and molding.
- Casting and Molding
Since many fossils are fragile and unique, preparators make precise replicas of them, called casts, for paleontologists
to study. Paleontologists rely on these fossil casts to study specimens that they might not have access to. For example many of the first fossils
found in the John Day Basin are stored in museums across the world. Making casts of important old or new finds allow scientists to share information
over great distances without endangering original specimens kept safely in collections here and in other museums.
Making a Mold.
- The fossil is embedded in a clay form.
- Layers of rubber and nylon are applied and plaster "keys are made to fill in any undercuts.
- A plaster "mother mold" is made that keeps this side of the mold rigid.
- The process is repeated on the other side.
- Airscribe Video
Airscribes are tools that work like miniature jackhammers. A hard metal needle pulses in and out at speeds of up to 30,000
cycles per second. The needle rapidly knocks off tiny bits of the rock that contains the fossil. Using an airscribe under a microscope lets
preparators clean off fossils big as dinosaurs and as tiny as ants. Before preparators stated using these handy air tools all the removal of rock
had to be done by hand with tiny chisels, dental picks and pins.
- The Preparator At Work (Photo of scientist working in lab setting).
A fume hood allows preparators to safely use a variety of chemicals.
Special glues dissolved in acetone or alcohol are used to harden or glue portions of broken fossils back together.
This paleontologist has specialized in a field called preparation. A preparator is a person who removes the fossil from the surrounding
rock in order to make it available for study or display. In order to be a preparator it helps to have a strong understanding of anatomy, chemistry,
geology, biology, ecology, and art among other things. Many preparators have an advanced degree in one or another of those fields. Many others have
come to the field of preparation through a lifelong love of the work and a very strong general background in the sciences or the arts. Perhaps the
most important qualifications, however, are steady hands and a lot of patience.
This mold, which looks like a plastic chew toy, is of a short-faced bear humerus. That is the bone in your upper arm.