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Drawing of a fossil preparator's hand excavating a juvenile Compsognathus dinosaur from rock, as the little dinosaur comes to life.

Visiting FossiLab, you may see volunteers working on several of these long term projects. Scroll down to read about them all, or click on a project in this list to jump directly to it.

Tiny vertebrate Fossils from the Late Cretaceous Dinosaur Teeth
A seive containing unsorted fossils from Haitian caves. Photographing Fossil Insects excavating Triassic fossils from Arizona Triassic Fossils from Arizona
Microscopic Foraminifera A tray full of rehoused bones from a disassembled skeleton Rehousing Fossils
Scientific drawing of a fossil shell Drawing Fossils with Camera Lucida
Microvertebrate Fossils from the Late Cretaceous

Not all fossils are big! Tiny bones, teeth, and other small animal fossils can provide rich and exciting information about biodiversity (the variety of species living in a place) in ancient ecosystems. FossiLab volunteers are helping Natural History Museum scientists by cleaning and sorting small fossils collected in North Dakota and Montana.

Curator Dr. Matthew Carrano and his colleagues travel regularly to several sites in Montana in search of fossil evidence of the small animals that lived alongside dinosaurs during the Late Cretaceous, 75 million years ago. They fill buckets with loose clay matrix at sites where small fossils are abundant, and ship the buckets back to the museum. Curators Dr. Anna K. Behrensmeyer and Dr. Hans-Dieter Sues similarly collect fossil-rich matrix in North Dakota and Montana at sites dating from just before and after the asteroid impact 66 million years ago that cause dinosaurs and many other Cretaceous organisms to go extinct.

In our behind-the-scenes lab we use a machine constructed from a bicycle wheel and a motor to loosen and rinse away the clay, then, in FossiLab, we examine what's left behind with microscopes in search of the many different kinds of tiny fossils. The work is slow but the tiny fossils are beautiful and fun to find.

A volunteer sits at a microscope and uses a brush to isolate small fossils from sediment.

A volunteer uses a brush to sort through washed sediment in search of small vertebrate fossils.

Clockwise from Top Left: We soak the matrix in water and pour it into sieves. The sieves go into our fossil washing machine which slowly and repeatedly dunks them in buckets of water. The clay matrix dissolves and passes through the holes in the sieves, leaving the tiny fossils behind. Once the sieves are dry, we pick through the mix looking for small bones and teeth among the debris. Click photos on left to zoom.

Assorted teeth from fish and crocodilians.Assorted fish vertebrae picked from the matrix.

Assorted teeth from several types of fish and crocodilians (left) and a collection of fish vertebrae (right) picked from sediment collected in the Hell Creek Formation. The smallest of these fossils are the size of a pencil tip. Click to zoom.

Follow this link to learn more about collecting fossil-rich sediment in the field: Getting Ready for the Last American Dinosaurs: Microvertebrate Fossils

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Dinosaur Teeth from the Late Cretaceous of Wyoming

Most of the small predatory dinosaurs (theropods) from the latest Cretaceous are known only from isolated teeth; few skeletons have been discovered.  Many of the teeth look very similar to each other, but there are small differences that indicate they came from different species.  How many theropod species were there? We are helping Smithsonian scientists answer this question by analyzing a large collection of small fossils, including dinosaur teeth, collected in Wyoming during the 1800s. The techniques used to study fossils have changed a lot since then, so this old collection is yielding interesting new results. We searched the collection for all the theropod teeth, and are measuring tooth height, width, the number and shape of the denticles that form the serrated edges, and other characteristics for each one.  Statistical analysis of the measurements will suggest how many distinct types of dinosaurs are represented by these 66 million year old teeth.

A volunteer uses a camera mounted on a microscope to photograph dinosaur teeth.

Photographs of fossil teeth taken through a microscope capture fine details of tooth structure, such as denticle (serration) shapes and spacing.

A large collection of small teeth, sorted into storage boxes.A therapod tooth photographed from different angles and labeled to show the types of measurements taken.>

Part of the collection, left. The first task was to sort through the hundreds of fossils to find all the dinosaur teeth. A Dromaeosaur tooth, right, showing the measurements we take off the teeth. Click to zoom.

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Photographing Fossil Insects

The Department of Paleobiology houses several spectacular collections of fossil insects. The Green River fossil collections include more than 120,000 insects, spiders, leaves, flowers, fish and other vertebrates preserved in sediments that settled on the bottoms of large lakes about 48 million years ago in parts of present-day Colorado, Utah and Wyoming.

FossiLab volunteers are working their way slowly through the collection, drawer by drawer, photographing the insects. As they work, the images they produce are displayed on a monitor so that visitors can see them. The images are being made available online so that researchers and insect enthusiasts alike can view the collection.

Photographing the Green River Formation insect collection.

The "insect corner" of FossiLab holds a small collection of the fossils, the microscope we use for photography, and some of the photos we have produced.

open collections drawers holding Green River Formation fossils.An enlarged photo of a fossil insect.An enlarged photo of a fossil insect.

Open collections drawers showing dozens of small rocks containing insect fossils (left), and photographs of two of the insects (right) Click to zoom.

Follow these links to view a slideshow of hundreds more Green River insect fossils and read more about the Green River Collections at the Smithsonian.

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Triassic Fossils from Arizona

On recent field expeditions to Petrified Forest National Park in northern Arizona, Museum curator Dr. Anna K. Behrensmeyer collected fossil-rich matrix dating from the Late Triassic Period (about 200 million years ago). The tiny fossils that FossiLab volunteers are excavating from the small blocks of rock are shedding light on the ecosystem that existed there at that time.

More than 350 good-quality specimens have been recovered from the matrix so far. These are mostly small teeth, but we also have discovered the jaw of a small pterosaur (a flying reptile) - likely a new species. Other specimens include archosaurs (ancestors of crocs and birds), early theropod dinosaurs, amphibians, and fish. The search goes on. We hope to find fossil evidence of early mammals.

Because the fossils are so tiny, we use very small tools - visitors may even see us applying tiny bits of glue to broken fossils with a cat whisker!

Excavating tiny fossils with the help of a microscope.

As we search for the tiny fossils and then excavate them from the matrix, a microscope is essential. A camera projects the work onto a TV screen so that visitors can watch.

A fish tooth excavated from the matrix.A curved, pointed theropod dinosaur tooth still embedded in matrix.The serrated tooth from a <em>Revueltosaurus</em> excavated from the matrix.

Three of the many small Triassic teeth from northern Arizona that have been discovered in FossiLab. Left to Right: A fish tooth, a theropod dinosaur tooth still in matrix, a tooth from a Revueltosaurus (a reptile). Click to zoom.

Follow this link to learn more, including why these fossils started their trip to FossiLab on horseback: Tiny Fossils, Big Excitement

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Museum Curator Dr. Brian Huber studies fossil foraminifera to answer questions about ancient changes in climate.

Foraminifera are tiny ocean-dwelling single-celled organisms that construct shells. Different species, identified by their unique shapes and by other shell features, inhabit a wide range of ocean environments, from the intertidal zone to the deep sea.  Benthic species live in sediments on the sea floor, while planktonic species live in the upper 300 feet or so of the ocean.  The shells of dead foraminifera accumulate on the sea floor, where there may be tens of thousands of shells per cubic centimeter (about a fifth of a teaspoon).

The fossil record of foraminifera is ancient, going back more than 550 million years. They are valuable indicators of past climate change because their shells are sensitive to changes in environmental conditions. We measure oxygen isotope ratios in fossil shells recovered from ancient sea beds to determine the geologic history of seawater temperature change near the ocean surface and on the ocean floor.

Several FossiLab projects involve picking or sorting 90 million year old foraminifera cored from rock in Tanzania that formed as ocean sediments accumulated during the Cretaceous.

Follow this link to learn more about drilling for the foraminifera in Tanzania, and visit the Fossil Preparation Page of this site to see how FossiLab volunteers use small paint brushes to pick up and move the minute shells.

A magnified image of a 90 million year old fossil shell from Tanzania.

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jumbled shells of many different foraminifera show a variety of species

Fossil foraminifera found in 120 million year old sediments collected from the deep sea floor, and a living species (inset). Click to zoom.

a volunteer uses a microscope to search through sediment for the fossils of tiny foraminifera

Above: A FossiLab volunteer uses a microscope to see the fossils of tiny Cretaceous foraminifera isolated from Tanzanian rock. Left: This high magnification image of a single shell was made with an electron microscope.

Rehousing Fossils

During the ongoing renovation of the National Fossil Halls, all of the mounted skeletons are being removed from exhibit, cleaned and conserved. Some of the skeletons have been on display for over 100 years, and all of them require a lot of care. Skeletons returning to exhibit in the renovated Fossil Halls will be mounted in new and more accurate poses that reflect what scientists have learned since the Fossil Halls were last renovated.

FossiLab volunteers are helping to take apart and rehouse the mounted fossil skeletons that are not going back on display, and you may see us removing bones from metal armatures. We make necessary repairs, stabilize the bones, and place them in archival storage boxes lined with form-fitted foam supports. Stored this way in our collections, they will be available for study by scientists and, perhaps, remounting in a future exhibit.

In addition to rehousing mounted fossils, we are conserving and rehousing some of the most scientifically and historically important fossils in our collections.

Dismantling a skeleton of Mesohippus, an ancestor of horses.

This plaque-mounted specimen of Mesohippus, an early species of horse, was dismantled in FossiLab.

Left: An open storage drawer showing four skulls and bones before they were properly housed. Right: Foam supports have been cut for these fossils, providing protection from vibration and making them less likely to break under their own weight. Click to zoom.

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Drawing Fossils with Camera Lucida

Scientists include high quality photographs of fossils in the research papers they publish about their discoveries. This allows others to study them and decide if they agree with the scientist's interpretations. Sometimes, if critical features of a fossil are hard to see in photos, a scientific illustrator will be asked to create precise drawings of the fossil. The drawings make the photos easier to interpret by highlighting the important features.

Artists volunteering in FossiLab use a microscope with a camera lucida attachment to make scientific illustrations of small fossils for Museum scientists. With this setup, the artist simultaneously sees a magnified image of the fossil and an image of his or her drawing. The effect is that the artist can "trace" the outlines of the fossil and any critical features, creating drawings that retain very accurate proportions.

Visit the Paleo Art website to learn more about scientific illustration techniques.

A volunteer uses a microscope with a mirror attachment to make precise drawings of small fossils.

A volunteer artist draws a small fossil while looking through a microscope. An arrow points to the round mirror of the camera lucida attachment, which reflects an image of the artist's hand, paper, and pencil into one of the microscope's eyepieces.

a small fossil seashell and two drawings of it made with camera lucida Diagram showing how the mirrored camera lucida attachment helps the artist

Above Left. A small fossil shell (shown in a box in the upper left corner) and two large drawings of it made using a microscope with camera lucida attachment. Above Right. A sketch shows how the mirror in the camera lucida attachment allows an artist to see both a magnified image of the fossil and his or her drawing. Click images to zoom. Art by James Morrison.

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Earlier FossiLab Projects:

Click on projects in this list to read about older FossiLab projects that have been completed or continue to be worked on in our behind-the-scenes lab.

A large fossil in a storage jacket Building Storage Jackets A field jacket containing Jurassic dinosaur fossils from Zimbabwe Jurassic Dinosaurs from Zimbabwe
Fossil leaves Fossil Leaves A t. rex claw and two plater replicas Making Fossil Replicas
The partially prepared skull of a brontothere Brontothere Skull A seive containing unsorted fossils from Haitian caves. Small Fossils from Haitian Caves
One side (called a valve) of an ostracode shell. Microscopic Ostracodes
Building Storage Jackets

Once excavated from the rock that has supported them for millions of years, the fragile, brittle fossils are susceptible to damage from vibration, gravity and improper handling. To protect them, we build form-fitted storage jackets with a soft inner layer of foam or felt and an outer layer of hard, fiberglass-reinforced plaster. Visitors to the lab can nearly always see storage jackets at some stage of construction. The work takes place in the large sandbox in the center of the room where sand supports the fossils during the early stages of jacket construction.

Visit another Department of Paleobiology website to read more and watch a video about storage jackets.

A volunteer opens a storage jacket containing a partial baleen whale skull from Aurora, North Carolina.

A stegosaurus plate resting in a opened storage jacket Storage shelving with jacketed and unjacketed fossils

Left: Building a jacket with plaster-soaked fiberglass cloth. Center: A Stegosaurus plate in an open storage jacket. The bolts that hold the two half jackets together are in the lower half jacket. Right: A view of our collections storage area showing many storage jackets as well as some fossils that have not yet been jacketed. Click to zoom.

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Jurassic Dinosaurs from Zimbabwe

Museum curator Dr. Matthew Carrano traveled to Zimbabwe in 2010 to collect fossils from dinosaurs that lived during the Early Jurassic Period, about 200 million years ago. The remains of dozens of Coelophysis (once called Syntarsus), a meat eating theropod, were found jumbled together in a "bonebed" exposed in the wall of a river canyon. Blocks of rock were cut from the canyon wall and shipped to FossiLab, where we are using air scribes, picks and needles to isolate the bones from the matrix. We also are preparing fossils of the larger plant-eating dinosaur Massospondylus that were found near the bonebed.

A field jacket contains a partially prepared block of rock containing many dinosaur bones.

A jumble of bones from the bone bed in a opened field jacket. Click to zoom.

A volunteer uses a pin vise and carbide needle to remove matrix from fossils from the bone bed.

A volunteer uses a pin vise and carbide needle to remove matrix from fossils from the bonebed.

Follow this link to read about the field work in Zimbabwe: Fossil Hunting under the Watchful Eyes of Lions

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Fossil Leaves

Dr. Scott Wing, Curator of Fossil Plants, has collected and studied thousands of fossil plants from Wyoming and South America for his research into the ecological responses to periods of climate change that occurred between about 70 and 40 million years ago. One period of rapid global warming, called the Paleocene-Eocene Thermal Maximum (PETM), provides the closest analog in earth history to current human-induced global warming. 

The leaves sent to FossiLab are still partly covered by rock matrix that must be removed to reveal as much of the fossils as possible. Leaf preparation is complicated by the fact that a block of rock may contain multiple overlapping leaves, only some of which are of scientific interest. To guide our work, the scientists draw hash marks on the rock to tell us which leaves they need to see and which areas of rock (and, at times, other leaf fossils) must be removed. We use a microscope during preparation to help us see the delicate fossils and avoid damaging them with our tools. The block of rock shown below on the left has been marked for preparation. The fossil shown below on the right is completely uncovered and ready for study.

using an air scribe and microscope to prepare leaf fossils

Using an air scribe to remove matrix covering a fossil leaf.

Left: A partly-covered leaf fossil marked for preparation. Right: A fossil that has been completely uncovered. Both leaves were found in Wyoming. Click to zoom.

Read Dr. Wing's Summer 2011 Field Dispatches to Smithsonian Magazine.

Access a classroom activity based on Dr. Wing's work to learn how the PETM fossils help us understand global warming in the past.

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Making Fossil Replicas

From the upper FossiLab window you can look down on a table where we are making replicas of the right foot bones from a Tyrannosaurus rex. These bones were collected by Museum staff in Montana in 2002 (read about the field work here) and were prepared for study by FossiLab volunteers. Now we are making several sets of plaster replicas, called casts.

First, we coat the fossils with silicon rubber to form a mold. The rubber follows every contour, nook and cranny of the bones, allowing the casts to replicate all the surface detail of the fossils. If the shape of a fossil is "simple," the mold is made in two halves. If it is more complex, the mold may be divided into three or more sections. Each section of silicon mold is reinforced with a plaster "mother mold" which helps maintain the proper shape. When the mold is completed, the fossil is removed and the inside of the mold is lined with fiberglass-reinforced plaster to form the cast.

We make casts for several reasons:

NMNH scientists frequently go on collecting expeditions to countries that require the return of any fossils found once they have been prepared and initial studies have been completed. Before we return the fossils, we make and retain exact replicas so that scientists here can continue to study them, and visitors can view them.

We make replicas of fossils in our collections that we wish to display but that are too fragile to withstand the vibrations and heat and humidity fluctuations they would experience on exhibit.  Displaying a replica of the rarest and most delicate fossils allows us to show visitors what they look like without endangering the fossils themselves.

Another reason to make casts is that we sometimes exchange replicas with other museums. Trading allows us to assemble more complete collections, making it easier for scientists to compare fossils that are housed in different museums. It also makes it possible for rare fossils to be displayed in many museums at the same time.

A volunteer prepares to fit together two halves of a cast of a T. rex foot bone.

A FossiLab volunteer works with two halves of a T. rex metatarsal bone cast.

T. rex claw and two casts.

A Tyrannosaurus rex claw and two plaster replicas. Click to zoom.

Several steps in the molding and casting of a fossil whale jaw bone are shown below.
The fossil lower jaw of a Pleistocene Grey whale is set in clay to mark the seam line in ghe mold.The fossil is coated in blue-green silicon rubber.

Left: The fossil lower jaw of a Pleistocene Grey whale found off the coast of Georgia is set in clay to mark the seam line in the mold. Right: The fossil is coated in blue-green silicon rubber to form the first half of the mold.

The two halves of the mold are lined with plaster and fiberglass cloth.The completed cast.

Left: The two halves of the mold are lined with plaster and fiberglass cloth. Right: The completed cast.

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Brontothere Skull

One of the most impressive views in FossiLab right now is of a set of very large brown teeth emerging from a block of rock that rests on the table in the center of the room. The teeth belonged to a brontothere, a rhinoceros-like relative of horses and tapirs that became extinct about 35 million years ago. We are using an air scribe to remove the rock matrix from the teeth and the surrounding skull.  The skull, shown below on the left, is upside down, so the teeth, which are attached to the upper jaw, are pointing upward.

Thousands of brontothere specimens have been collected in North America and Asia, allowing scientists to document the many ways that brontothere species changed during their 20 million years of evolutionary history. Reconstructions of some of the many species are shown in the historic drawing by Charles R. Knight shown below, right. 

A volunteer uses an air scribe to chip away the rock matrix covering a brontothere skull.

A volunteer uses an air scribe to chip away the rock matrix covering a brontothere skull found in South Dakota.

Partially prepared brontother skull. Drawings of several different species of brontotheres showing the variation in skull and horn size and shape.

Left: The partially prepared brontothere skull. Right: Life-like drawings of different species show some of the variation in skull and horn size and shape that evolved in the brontotheres. Click to zoom.

Follow this link to read. Learn why the brontothere is the "oldest" project in FossiLab: Dental Work, Anyone?

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Small Fossils from Haitian Caves

In the 1920s, scientists from the Smithsonian collected fossils dating from the Pleistocene from several caves in Haiti. Descriptions of larger fossils, including the bones of extinct ground sloths and birds were published in scientific journals, but huge numbers of bulk-collected small bones, including those of birds, bats and other mammals, reptiles and amphibians, were left unsorted and undescribed.

A circular sieve contains a jumble of small bones and debris.

Volunteers are now cleaning and picking through this material in FossiLab. The top photo on the right shows unsorted bones that have been washed in a sieve. Sorting is done first by bone type (femur, skull, vertebra, etc.) then by animal type (bird, frog, bat, etc.). The many labeled trays of tiny bones, including those shown in the bottom photo, will be stored in our collections, available for study by researchers interested in island ecosystems, evolution and extinction.

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Humdreds of tiny bones have been sorted into boxes.

Click to zoom.

Ostracodes from the Cretaceous

Museum Curator Dr. Gene Hunt studies fossil ostracodes to answer questions about evolution, extinction and changes in climate and other environmental conditions.

One shell (called a valve) of a fossil ostracode.

The fossilized shell of an ostracode from the Cretaceous. Click to zoom.

Ostracodes are microscopic crustaceans related to shrimp and crabs. They have lived in the Earth’s waters and moist soils for hundreds of millions of years, evolving into thousands of different species and living in many different environments. Most ostracodes are about 1 millimeter long (about 1/25th of an inch) or smaller. Their bodies are protected by two hard, clam-like shells that can persist as fossils long after the animal dies and the soft parts decay. The long fossil record of ostracodes, their wide geographic distribution and their abundance make them ideal research subjects for Dr. Hunt's studies.

Recently, FossiLab volunteers have been searching for ostracode fossils in Late Cretaceous marine sediments from northern Mississippi. The ostracodes lived in sea water that covered most of that state during that time period (65-85 million years ago). One of the fossil collecting sites is shown in the photo to the right. Each hole carved into the hillside is a place where a sediment sample has been made. Fossil ostracodes found in sediment collected at the bottom of the hill are the oldest; moving up the hillside, the sediment samples, and the fossils they contain, get younger. After the sandy clay is washed, it is brought to FossiLab, where the search for the tiny fossils began.

Visit the Fossil Preparation page to see how FossiLab volunteers use small paint brushes to pick up and move the minute shells.

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A scientists has scaled a steep hillside to dig ostracode-containing sediments.

Click to zoom.


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