Tag Archives: fossils

Rethinking history and picturing deep time

Louis Figuier’s 1863 book The World Before the Deluge was a time machine between two covers.  By the mid-nineteenth century, geologists knew that different rock layers and the fossils entombed in them corresponded to distinct periods of time, ages when animals and plants unlike any known to modern man had populated the globe.  Figuier took his readers on a grand tour of these geologic periods—or rather, he did so with the assistance of Édouard Riou, whose evocative engravings brought these extinct environments back to life.

Each engraving showed readers a primordial landscape characteristic of a phase of prehistory.  The result was a sort of highlights reel of earth history, a sequential arrangement of what the historian of science Martin J.S. Rudwick calls “scenes from deep time.”

Riou’s illustrations have long since lost their scientific value, but they still pack a visual wallop.  In this image, torrential rains hammer the surface of a newborn globe:

Trilobites and other marine invertebrates wash up on the shore of the Silurian sea:

The forests of the Carboniferous:

Two dinosaurs, depicted as the stocky and elephantine reptiles that early Victorians assumed they were, engage in mortal combat:

The emergence of large mammals:

A primeval flood inundates northern Europe:

The appearance of (notably white and European) humans:

And finally, a later, “Asiatic” flood, perhaps the one described in Genesis and other ancient texts:

If you’ve ever read a paleontology textbook, visited a natural history museum, watched a documentary on evolution, or stepped into a science classroom, you’ve probably seen a modern variation of these sequential deep time scenes.  Paintings in books, dioramas in museums, and CGI clips on TV often take the form of the “prehistoric highlights reel” that Figuier and Riou helped popularize.

And although the science of paleontology has changed a great deal since the 1860s, the organisms that populate our own scenes from deep time tend to correspond with those Riou associated with specific periods.  The dates assigned to the scenes have changed (and in the case of he dinosaurs, the physiology of the animals has changed, too), but the cast has remained much the same.  The scenes start out with marine invertebrates, then move on to primitive chordates and fish, then amphibians and early terrestrial organisms, then dinosaurs and other Mesozoic reptiles, then mammalian megafauna, and finally humans.  I had a lot of books on prehistoric life when I was a kid, and the sequence of illustrations was pretty consistent across most of them: marine invertebrates, jawless fish, jawed fish, amphibians, dinosaurs, mammals, and Homo sapiens.

This sequence may seem inevitable; after all, it’s the order in which the major groups of organisms appeared.  But there’s a sense in which it’s misleading.  The illustrations tend to be much better at highlighting when groups of organisms appeared or were especially prominent than they are at indicating how long they flourished.

Take reptiles, for example. Many illustrators will throw one in around the late Carboniferous to mark the emergence of the first reptiles, or perhaps include a picture of the sail-backed Dimetrodon in the Permian. Pictures of reptiles then dominate the Mesozoic, and then tend to disappear from pictorial sequences and time charts altogether after the age of dinosaurs.

But reptiles didn’t go extinct 65 million years ago.  Nor, for that matter, did the dinosaurs themselves.  Birds are advanced theropod dinosaurs, and living bird species outnumber mammals species by two to one.  Extant reptile species outnumber mammal species, too.  But you wouldn’t know this from looking at pictorial deep time sequences and geologic time scales.  Illustrators are keen on reptiles and birds when they first appear, or when they’re the biggest terrestrial animals going.  Once you hit the end of the Cretaceous Period, however, it’s as if we assume that reptiles and their descendants ceased to exist, or at least ceased to be relevant.  Indeed, we call our own time the “Age of Mammals,” but it would be just as accurate to keep calling it the “Age of Reptiles.”

The artificiality of deep time imagery is even more apparent when you look at fish.  Illustrators highlight fish when they’re the only vertebrates around, but once amphibians show up and start colonizing the land, fish more or less vanish from the pictures.  Likewise, you don’t see many amphibians in illustrations of scenes dating from after the first appearance of reptiles.  And invertebrates tend to disappear entirely once animals with backbones evolve, even though they make up more than 95% of all extant species described so far.

These charts and sequential images also tend to favor terrestrial over aquatic life.  Marine organisms are plentiful in scenes of early eras, when there’s no life on land.  But once terrestrial animals appear, many geologic time scales omit marine life altogether, except for the occasional aquatic reptile from the Mesozoic (presumably included because they look really cool).

You can see the same sequence of organisms in illustrated charts and tables of geologic time.  Take a look at this one produced by CliffsNotes.  Invertebrates for the earliest periods populate the oldest periods at the bottom, and then it’s fish, terrestrial animals, dinosaurs, and mammals.  Not a single invertebrate after the first appearance of insects.

Here’s another one from a professional development site for teachers.  It’s pretty consistent with the one above.  Invertebrates, fish, plants, amphibians, dinosaurs, large mammals, and finally man up at the top.

The point I’m belaboring here is that pictorial sequences of earth history and illustrated geologic time charts are as notable for their omissions as they are for what they include.  There’s a sort of implicit narrative thrust at work here, focused on organisms that are vertebrate, terrestrial, and warm-blooded.  Organisms, in other words, that seem most relevant to our own origins.

Now, I’ve never needed an excuse to discuss extinct organisms here before, but this post isn’t one of my gratuitous prehistoric indulgences.  I raise the issue of scenes from deep time because it offers insights into the ways we think about the more recent, human past.

We might compare the treatment of some historical subjects in textbooks and survey courses to depictions of organisms in pictorial sequences of deep time.  Just as illustrators render some animal groups invisible once a more recent group arrives on the scene, so we tend to render Indians invisible after, say, King Philip’s War, Jacksonian removal, or Wounded Knee.  But Native Americans didn’t vanish after these important turning points.  They might have ended up in a different location, but they didn’t become extinct or irrelevant, any more than amphibians became extinct once animals started laying amniotic eggs.

And the descendants of Spanish colonists in the American Southwest didn’t cease to exist after the mid-1800s, when Anglophone Americans took political control of the region.  They were there the whole time, just as birds kept fluttering along through the mass extinction of 65 million years ago and the emergence of large mammals afterward.

In the same way, just as it’s misleading to ignore marine life and focus exclusively on terrestrial life after the movement of the first organisms into land, it’s also misleading for history books and courses to ignore the Southwest after the passage of the “frontier” era, or to be attentive to southern history only during the Civil War, New South, and civil rights eras.  And our discussions of such important changes as the Industrial Revolution shouldn’t blind us to the fact that most Americans remained tied to agriculture long after the first steam engines started puttering, just as most organisms remained invertebrates long after the first backbones appeared.

Our selective memory of history suffers from the same problems as our selective memory of the story of the life on this planet.  We need to remind ourselves to step away from selective scenes of the past to take in the sweep of the whole drama.  And we need to stop thinking of history in terms of a “highlights reel” of status scenes, and start thinking of it as a totality.

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A dinosaur in living color

One of the many dinosaur books I had as a kid was a coloring book that came with a sing-along cassette.  The only song from that tape that I still remember was about dinosaur colors.  “Colors of the rainbow, any will do/Dinosaur colors are up to you,” went the refrain.

That song always struck me as a real downer.  Being able to make your dinosaurs whatever color you wanted was little consolation to those of us who would’ve given our right arms to know what color they really were.

Well, we don’t have to wonder anymore, at least not when it comes to some dinosaurs.  One of the most exciting paleontological breakthroughs of the last decade was the discovery of melanosomes in feathered dinosaur specimens.  Examination of these microscopic structures allowed scientists to give us a much more precise picture of what some types of dinos looked like.  When news of this broke, I felt like the earth had shifted.  For the first time, we were dealing with something other than educated guesswork when it came to dinosaur coloration.

The only thing more exciting would be seeing an actual dinosaur in the flesh with its integument and coloration still intact.  And, ladies and gents, that’s exactly what just happened.  From National Geographic:

The tail of a 99-million-year-old dinosaur, including bones, soft tissue, and even feathers, has been found preserved in amber, according to a report published today in the journal Current Biology.

While individual dinosaur-era feathers have been found in amber, and evidence for feathered dinosaurs is captured in fossil impressions, this is the first time that scientists are able to clearly associate well-preserved feathers with a dinosaur, and in turn gain a better understanding of the evolution and structure of dinosaur feathers.…

Inside the lump of resin is a 1.4-inch appendage covered in delicate feathers, described as chestnut brown with a pale or white underside.

CT scans and microscopic analysis of the sample revealed eight vertebrae from the middle or end of a long, thin tail that may have been originally made up of more than 25 vertebrae.

Here it is, the tail of an honest-to-goodness dinosaur, still in the flesh after nearly a million centuries.  This is a wonderful time to be alive!

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Photo by R.C. McKellar, Royal Saskatchewan Museum via National Geographic (http://news.nationalgeographic.com/2016/12/feathered-dinosaur-tail-amber-theropod-myanmar-burma-cretaceous/)

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A peek at the awesomeness coming in 2017

Hey, here’s a pleasant surprise!  USA Today has an excerpt from Dragon Teeth, the Bone Wars novel coming out next May by the late, great Michael Crichton.  Looks like the main character is a young man from a well-to-do Philadelphia family who joins the first big Gilded Age fossil rush.

The dust jacket looks pretty cool, although it’s a little odd to see a Tyrannosaurus on the cover of a novel set in the 1870s.  Some material now recognized as belonging to T. rex did turn up in the late 1800s, some of it discovered by fossil hunters involved in the Cope-Marsh feud.  In fact, Cope himself published a description of a couple of vertebrae from South Dakota that have since been identified as T. rex remains.  But the name Tyrannosaurus rex didn’t appear in the scientific literature until about thirty years after Cope and Marsh started duking it out.  No big deal, though—and not the first time Tyrannosaurus has made a somewhat chronologically-inappropriate appearance on the front of a Crichton novel.  After all, most editions of Jurassic Park featured a T. rex on the cover, even though the Jurassic Period ended almost eighty million years before the tyrant lizard king showed up.

While we’re on the subject of prehistoric beasties and awesome stuff coming out in 2017, have you seen the Kong: Skull Island trailer yet?  I don’t know if I’ve mentioned this here before, but I’ve been a huge King Kong fan since I was about six.  (The fact that the ’33 film was chock full of dinosaurs might’ve had something to do with it.)   Maybe I should add a “Gratuitous Giant Ape Posts” category since I’m already subjecting you folks to periodic dino digressions.

The movie’s set in the Godzilla universe, and this ginormous, bipedal Kong seems to have more in common with the Toho version than the old school one that climbed the Empire State Building with a blonde in his hand.  Me, I prefer the original take on Kong, and I’m disappointed by the lack of dinosaurs in the trailer, but this is still my most anticipated movie of 2017.

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Beast in the basement

Whenever I’m down in the McClung Museum’s basement, I stop to pay my respects to an old friend.

img_2073Old, that is, in a relative sense.  This is a cast facsimile of a T. rex skull rather than the real thing.  But this bad boy (girl?) and I go back a long way.  My dad used to indulge my dino obsession by taking me to the McClung Museum on weekends so I could hang out in the old geology and fossil exhibit, where the T. rex skull went on display sometime back in the early or mid-nineties.

That exhibit has now gone the way of the specimens it once showcased.  The McClung’s current geology and fossil gallery opened in 2002 with some new dino skull casts and gorgeous dioramas, but sans tyrant lizard king.  Now the T. rex is enjoying semi-retirement downstairs, although we wheel him out for school tours from time to time.

Those of you who are fellow paleo-nerds may recognize the skull as a copy of one of the most famous dinosaur specimens in the world: AMNH 5027, excavated by the great fossil hunter Barnum Brown in Montana back in 1908.  The original skull is on display in the American Museum of Natural History in New York…

By Futureman1199 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons

By Futureman1199 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons

…right in front of the skeleton it was once attached to.  Fossil T. rex skulls are so heavy that it’s hard to mount them at standing height, so most museum specimens have lighter copies stuck on the ends of their necks.

By David Cornforth [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons

By David Cornforth [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons

AMNH 5027 wasn’t the first T. rex specimen to be described.  But it was the first to be found with an intact cranium, making it a popular choice for replication.  (Check out the wonderful Extinct Monsters blog for the history of T. rex on display and the proliferation of 5027 clones in museums all over the world.)  If you’re at a museum that has a tyrannosaur cast, one easy way to tell if it’s a copy of 5027 is to look at it head-on.  The original looks a bit smashed on the upper left side, as if it’s starting to collapse inward like a rotting pumpkin.  You can see the distortion in this photo of UC-Berkely’s replica:

By BrokenSphere (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons

By BrokenSphere (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)%5D, via Wikimedia Commons

One other thing to take note of when you’re looking head-on at a T. rex is the position of the eye sockets.  Although they’re on the sides of the head, they’re oriented so that the eyes themselves would have faced forward, which probably meant good depth perception.  In fact, research by Kent Stevens indicates that T. rex had superb vision.  Combine an eagle’s eyesight, an exceptional sense of smell, and a bone-crushing bite, wrap it all up in a forty-foot package, and you’ve got one of the most remarkable carnivores in the history of life on this planet.  In other words, it’s probably not a good idea to stand still and hope he doesn’t notice you.

Anyway, as awesome as this guy looked in the old exhibit, I’m sort of glad he’s taken up quarters behind the scenes.  As a kid, I used to stand in front of his display case and wonder what it would feel like to run my hands across those bony protrusions and along those fearsome jaws.  Now I don’t have to wonder, and it’s one of many reasons I love my job.

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When scientific specimens become historic artifacts

In the summer of 1909, just after vacating the White House, Theodore Roosevelt killed a lion in Kenya as part of a collecting expedition for the Smithsonian.  Now the mounted cat is going back on exhibit at the National Museum of Natural History after spending twenty years in mothballs.  Here’s Sarah Kaplan’s fascinating piece at The Washington Post:

The past century has taken a toll on the majestic creature. The lion’s tawny fur is crushed in places, and his rumpled mane gives him the appearance of having bed head. A portion of his ear is clipped, chunks of fur are missing, and his glass eyes have gone foggy with age.

Conservator Ron Harvey surveyed the mount, assessing the damage, deciding what to repair and what to leave as is.

“I want him to look his best,” he explained. “But it is 100 years old. I want to maintain that sense of history too.”

The job of a natural history conservator goes far beyond simple aesthetics. Harvey must maintain the specimen’s scientific usefulness, ensuring that it can be studied by future generations. He also wants to preserve it as a historical artifact — an object that can tell us about our past and its own. When museum visitors look at this mount in six months, Harvey hopes they’ll get a sense of how it got to the museum, what it meant when they arrived, what it stills mean today.

“What story did this lion and Roosevelt want to tell us?” Harvey wondered. That’s what he aims to conserve.…

After consulting with museum conservation specialist Cathy Hawks, he decided to leave the lion’s glass eyes — which are cloudy and crizzled from a phenomenon called glass disease — as they are. They’re historic artifacts too, after all, and they’re suggestive of the lion’s old age and impressive backstory. On top of which, it would probably cause more damage to try to take them out.

“What we’re trying to do in conservation is preserve and extend the life of . . . this body that has not been sapped of all its knowledge,” Harvey said.

He noted that the specimen has been cited in scientific journal articles as recently as 2010, and that scientists are developing new tools for research all the time. There may be other stories — about lion biology, East African ecosystems, 20th century taxidermy methods — buried inside this specimen, waiting for someone with the right question and the right tools to answer it.

Roosevelt’s lion is a working scientific research specimen, but it’s also a historic artifact.  It reminds us that science is a human process embedded in the time and culture in which it takes place.  The National Museum of Natural History, the American Museum of Natural History in New York, the Peabody Museum at Yale, and the Natural History Museum don’t just preserve the record of life on earth, but also the record of how we’ve come to understand it.

Mounted lions from Roosevelt's Smithsonian safari. Image from Smithsonian Institution Archives (negative no. 24881 or NHB-24881) via Wikimedia Commons

Mounted lions from Roosevelt’s Smithsonian safari. Image from Smithsonian Institution Archives (negative no. 24881 or NHB-24881) via Wikimedia Commons

That’s one of the things that makes a visit to venerable old natural history museums so special.  As I’ve said before, a stroll through the fossil galleries of the American Museum of Natural History is almost like a tour of milestones in the history of vertebrate paleontology in the late nineteenth and twentieth centuries.  Seeing any real dinosaur fossil is a treat, but at the AMNH you’re also seeing the life’s work of legendary figures like Barnum Brown, Henry F. Osborn, Charles H. Sternberg, and Roy Chapman Andrews.  You’re standing in the presence of giants in a dual sense, both the remains of long-dead creatures and the ghosts of those who brought them to light.

If you’re planning a trip to the AMNH, I heartily recommend reading Douglas Preston’s Dinosaurs in the Attic: An Excursion into the American Museum of Natural History before your visit.  It’s an engrossing reminder that natural history and human history are intertwined, and that museums house stories as well as specimens.  Thousands of stories, millions of stories—stories behind every pair of glass eyes, mounted on every metal armature, locked away in every drawer.

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A Crichton novel on the Bone Wars is coming

I’d like to apologize for that ear-piercing noise that shattered windows all over the Western Hemisphere last night.  That was me shrieking with ecstatic delight in reaction to this:

HarperCollins Publishers has acquired World English rights to DRAGON TEETH by bestselling author Michael Crichton. Harper Publisher Jonathan Burnham and Executive Editor Jennifer Barth negotiated the deal with CrichtonSun’s Sherri Crichton through Sloan Harris and Jennifer Joel of ICM Partners and Michael S. Sherman of Reed Smith LLP. The book will be published in May 2017 in the U.S., U.K., Canada, Australia, New Zealand and India.

Michael Crichton’s DRAGON TEETH follows the notorious rivalry between real-life paleontologists Edward Drinker Cope and Othniel Charles Marsh during a time of intense fossil speculation and discovery in the American West in 1878. The story unfolds through the adventures of a young fictional character named William Johnson who is apprenticed first to one, then to the other and not only makes discoveries of historic proportion, but transforms into an inspiring hero only Crichton could have imagined. Known for his meticulous research, Crichton uses Marsh and Copes’ heated competition during the ‘Bone Wars,’ the golden age of American fossil hunting, as the basis for a thrilling story set in the wilds of the American West.

Sherri Crichton has been working to honor her late husband by creating the Michael Crichton Archives through her company CrichtonSun. “When I came across the DRAGON TEETH manuscript in the files, I was immediately captivated. It has Michael’s voice, his love of history, research and science all dynamically woven into an epic tale.” She traced its genesis back to correspondence between Crichton and Professor Edwin H. Colbert, Curator of Vertebrate Paleontology at the American Museum of Natural History. “DRAGON TEETH was clearly a very important book for Michael. I’m so pleased to continue the long relationship that he shared with HarperCollins with its publication.”

The “Bone Wars”—the bitter feud between rival naturalists Edward Cope and O.C.Marsh—pretty much defined vertebrate paleontology in the United States during the late nineteenth century.  As ugly as the Cope-Marsh spat was, it played a large role in bringing to light the fossil riches of the American West, since the two men financed prospecting and excavation in some of the country’s most important bone beds.  A lot of the “classic” dinosaurs that are household names first came to scientific attention in the papers they published.  Their rivalry has fascinated me since I was a kid; in fact, when I was an undergrad, I did my capstone research project on it.

Anyway, it’s Crichton. It’s dinosaurs. It’s American history.  As they used to say in the beer commercials, “Boys, it just doesn’t get any better than this.”

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Dino discoveries at the McClung Museum

Did I hit the special dino exhibit at the McClung Museum on opening day?  You better believe I did.

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Our knowledge of dinos has increased almost exponentially in the past decade or two, partly because there are more people engaged in the business than ever before, but also because of new specimens and new techniques for studying them.  New knowledge and new techniques are what the exhibition Dinosaur Discoveries: Ancient Fossils, New Ideas is all about.  Organized by the American Museum of Natural History in New York, it offers a look at some of the things scientists have learned in the past decade or so, and explains how they’ve learned it.  If you developed an interest in dinosaurs back in the heyday of the nineties but fell out of the loop later, or if you were a dino-obsessed kid who hasn’t picked up a paleo book in decades, this exhibit will give you a taste of what’s been going on lately in the world of terrible lizards.

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Take computer modeling, for example.  Dino bones tend to be big, heavy, and fragile, which puts limits on the things you can do with them in a lab.  Researchers can manipulate a virtual skeleton in ways that would be impossible with the genuine article, so they can study, say, the neck vertebrae of a sauropod to get a sense of what the living animal’s posture might have been like.  You know those pictures of long-necked herbivores with their heads held erect like enormous giraffes?  Turns out sauropods might not have been browsing up in the treetops after all.

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Here’s a Mesozoic arsenal: stegosaur plates and a spike, and an ankylosaur tail club.  Or were some of these things intended to win over mates rather than fend off carnivores?

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We’ve all seen images of Triceratops facing off against T. rex.  But as formidable as those horns and that bony frill look…

 

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…the headgear isn’t as impressive on smaller relatives, such as Protoceratops.  That suggests ceratopsians were using their cranial adornment for something besides dueling with predators.

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And speaking of T. rex, one of the most interesting paleontological debates involves whether the tyrant lizard king was a fast runner.  (I think it’s interesting, anyway, and in the event you ever find yourself in the presence of a tyrannosaur, I dare say you’ll take an intense and sudden interest in it, too.)  How do you gauge the top speed of an animal that died tens of millions of years ago?  This exhibit will let you see how scientists crunch the numbers, and where the numbers themselves come from.  And the news is surprisingly not that bad for those of you in the habit of driving jeeps around island theme parks during power outages.

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Some of the most fascinating dino discoveries of the past couple decades have come from the early Cretaceous deposits of Liaoning Province in northeastern China.  Animals and plants either died in or washed into still lakes before volcanic ash buried them, creating a low-oxygen environment that kept the remains intact and preserved the fossils in exquisite detail.  Because of these ideal conditions, we know that some dinosaurs from Liaoning—such as Sinosauropteryx, Microraptor, and Sinornithosaurus—had a feathery covering.  These Chinese finds have shed quite a bit of light on the relationship between birds and extinct dinosaurs and the evolution of flight.

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Dinosaur Discoveries will be at the McClung until August 28.  I definitely recommend a visit for those of you in the Knoxville area.  It’s not an assemblage of original specimens, but the casts and models are lovely, and there are plenty of interactive elements.  I love the idea of an exhibit geared toward teaching not just what scientists know, but how they know it and how much remains to be determined.  It underscores the idea of science as a process—as a set of questions and contested answers—rather than an inert body of facts that just appears out of nowhere in the pages of textbooks and on Wikipedia.

History, too, is a process  of inquiry.  And I think we should more fully exploit this same approach when it comes to history exhibits and other historical media aimed at the public.  One of the big problems historians face when it comes to advocating for the discipline is the fact that so many people don’t really understand what we do or how we go about doing it.  Since exhibits are one of our primary means of communicating with the public, we should be using them not just to convey information about our subject matter, but to give people a sense of how historians go about their work, what constitutes historical thinking, and what the possibilities and limitations of historical investigation are.  We should be using exhibits to convey information, but we should also use them to demonstrate that this information is the result of historians asking questions, figuring out how to answer them, and throwing those answers into competition with one another.

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