Extinct Monsters: The Marsh Dinosaurs, Part I

Click here to start the Extinct Monsters series from the beginning.

Othneil Charles Marsh was, along with Edward Drinker Cope and Joseph Leidy, one of the preeminent vertebrate paleontologists of the 1800s. Under contract with the U.S. Geological Survey, Marsh supervised numerous field expeditions to the American western interior. He personally took part in only four field seasons (much of the actual collecting was led by John Bell Hatcher), but he described and named over 500 new species of extinct animals. Marsh and Hatcher’s pioneering fossil-hunting trips in frontier lands have been recounted well and often (Jaffe’s The Gilded Dinosaur remains the definitive account), so I won’t get into that here. Discovery and excavation are only the first steps in a fossil’s journey, so this post concerns what happened next to the 80-some tons of material Marsh and his colleagues collected for the USGS.

OC MArsh, 2nd row center.

Marsh (rear center) and his students pose in their field regalia.

The major stipulation behind Marsh’s federal funding was that the fossils he collected had to be transferred to the Smithsonian Institution when he was through studying them. Starting in 1886, fossils started traveling by the trainload from Yale, Marsh’s home institution, to Washington, DC. The first four shipments were comparatively small, consisting of only a few hundred prepared specimens apiece. However, when Marsh died in 1899, the Smithsonian received a final shipment of some 15,000 specimens, most of which had yet to be removed from their field jackets. It is unknown exactly how many specimens compose the Marsh Collection, but they are enormously varied, ranging from minuscule teeth and vertebrate of fish and amphibians to gigantic dinosaur bones weighing as much as 2000 pounds apiece. To this day, the Marsh Collection remains the largest assemblage of fossil material at the Smithsonian, and it includes the holotypes of Diplodocus longus, Camptosaurus nanus, Ceratosaurus nasicornis and several other dinosaurs. It also contains a spectacular variety of fish, amphibians, crocodilians, snakes, and mammals, many of them type specimens, from the Mesozoic and Cenozoic.

Although Marsh named hundreds of species from the fossils his teams collected, his published descriptions were generally quite brief. Because of Marsh’s shenanigan-filled rivalry with Cope, he would often rush new discoveries to publication, providing a couple paragraphs or less of descriptive text. It was up to the next generation of paleontologists to sort through this taxonomic headache, and much of the credit is deservedly given to Charles Gilmore. Having joined the Smithsonian in 1903 as a preparator, Gilmore dedicated much of his career to meticulously studying and re-describing Marsh’s fossils. Along with Norman Boss and James Gidley, Gilmore created most of the iconic dinosaur mounts at the National Museum of Natural History, many of which were constructed with Marsh Collection fossils.

The Edmontosaurus

When Gilmore started work at the Smithsonian, the Marsh Collection was stored in a rented building at 10th and C NW. Only a minority of the specimens had been prepared, and most were still in their plaster field jackets. Gilmore’s detailed daybooks reveal that he usually split his days, spending mornings on fossil preparation and afternoons on research and description. Many of the hours spent on preparation involved building mounted skeletons for public display. The early 20th century was a golden age for fossil displays in museums – mounts were springing up seemingly overnight in natural history institutions on both sides of the Atlantic. In 1903, the Smithsonian already had several fossil mounts in the original United States National Museum (now the Arts and Industries building), including BasilosaurusMegaloceros, and plaster replica of Hadrosaurus. Gilmore got to work right away on the institution’s first original dinosaur display – a relief mount of Edmontosaurus.

This relief-mounted Edmontosaurus was the first complete Mesozoic dinosaur displayed at USNM. Photo courtesy of the Smithsonian Institution Archives.

Photo by author.

The Edmontosaurus was positioned an inaccessible 30 feet in the air from 1981 to 2014. Photo by the author.

The skeleton (USNM 2414) was collected by Hatcher in Niobrara County, Wyoming, sometime between 1889 and 1892. It was first described by Marsh as Claosaurus annectens in 1892, and it has gone by several other names since, including Thespesius, Trachodon, and Anatosaurus. Specialists now agree that it belongs in the genus Edmontosaurus, but E. annectens remains a distinct species. This specimen is therefore significant not only as the Smithsonian’s first mounted dinosaur, but as a name-bearing holotype. In addition, USNM 2414  is the second American dinosaur mount composed of original fossils, following another Edmontosaurus built at the Peabody Museum of Natural History in 1901.

The Edmontosaurus has been on nearly continuous display since 1904. When the USNM moved to the building now known as the National Museum of Natural History in 1910, the Edmontosaurus made the journey across the mall in a horse-drawn carriage. It was re-installed along the south wall of the Hall of Extinct Monsters, although unfortunately somebody dropped the skull on the stairs during the move. The mount remained in the same position during the 1963 renovation, but in 1981 it was moved about 30 feet up the wall to increase space at ground level. In this position, the mount could only be viewed properly from the hall’s mezzanine ramp. Exhibit designers at the time incorrectly assumed that there would be no new interest in researching a century-old skeleton – and over the years the museum has had to turn down many requests to study this important holotype.

Partially mounted Edmontosaurus

The partially-mounted Edmontosaurus in the Research Casting International workshop. Source

The Edmontosaurus was one of the first historic dinosaurs to be restored by the technicians at Research Casting International in preparation for the new National Fossil Hall. Since had been mounted in relief, the left side of the animal had never been completely freed from its original matrix. Nevertheless, the RCI team was able to completely extract the bones, ossified tendons and all. In the new exhibit, the Edmontosaurus will be rebuilt as a three-dimensional standing mount, sharing a platform with the Nation’s T. rexThescelosaurus, and other denizens of Cretaceous North America.

The Triceratops

Upon completing the Edmontosaurus mount, Gilmore and Boss moved on to a more ambitious project: a free-standing mount of Triceratops, the first of its kind in the world. The Smithsonian had already constructed a papier-maché Triceratops skeleton for the Pan-American Exposition in Buffalo, based on an 1891 reconstruction by Marsh. The new mount, however, would be the first to incorporate original fossil material, and its proportions and posture were substantially altered to reflect a decade’s worth of new research. This new Triceratops mount would go on to define the popular and scientific understanding of this animal for the next century.

The Triceratops in the Hall of Extinct Monsters, circa 1922. Photo courtesy of the Smithsonian Institution Archives.

Triceratops fossils were famously introduced to Marsh in 1887 by way of a partial skull roof with a pair of two-foot horns, which he (not unreasonably) thought belonged to an extinct bison. The following year, however, Hatcher’s team found a treasure trove of more complete Triceratops material in Wyoming, which clarified that the animal was actually an ornithiscian dinosaur. Hatcher continued to collect from this site for the next three field seasons, amassing a substantial collection of Triceratops material, including several skulls. All told, the Wyoming Triceratops material represented about 50 individuals, but most were disarticulated and none were complete. It fell upon Gilmore and Boss to assemble a composite skeleton. The completed mount contains bones from at least seven individuals of varying sizes. Most notably, the skull and left humerus are too small compared to the rest of the skeleton. Several missing elements were sculpted, but Gilmore ensured that these reproductions were colored differently from the fossils to make them immediately recognizable to viewers. The most significant substitutions were the hindfeet, which came from an Edmontosaurus.

Gilmore’s mount differs from Marsh’s 1891 Triceratops illustration in several ways. Marsh gave Triceratops too long a torso by including six extra dorsal vertebrae, a problem which was rectified in the mount. Additionally, Gilmore refrained from reconstructing the nasal horn as Marsh had done, because there was no way of knowing how long to make it. Most notably, after attempting to articulate the skeleton, Gilmore concluded that the fully upright forelimb posture Marsh had reconstructed was not possible because “it would so elevate the anterior portion of the body as to have made it a physical impossibility for the animal to reach the ground with its head.” Gilmore instead gave his Triceratops sprawling forelimbs, a choice that resulted in decades of very uncomfortable-looking ceratopsids in paleoart. Although this issue has yet to be resolved, modern biomechanical research suggests that Marsh’s straight-legged Triceratops may have been correct, after all.

The Triceratops mount was completed in 1905, and Gilmore humbly reported it as “a fairly accurate representation of the skeletal structure of this particular reptile.” It was an impressive 19 feet, 8 inches long, 8 feet, 2 inches tall at the hip, and sported a six-foot skull. Placed on a pedestal textured to resemble the Lance Formation rocks in which it was found, the Triceratops was unveiled in the Arts and Industries Building. It was moved to the Hall of Extinct Monsters in 1911.

The Triceratops as it appeared in the 1963 display of fossil reptiles.

During the 1963 renovation, the Triceratops mount was rotated to face west and placed in the corner of a large central platform which it shared with Diplodocus and others dinosaurs. In 1981, the Triceratops was brought to the front of the gallery, on its own pedestal in the northeast corner of the dinosaur hall. In this position, it was one of the first specimens visitors encountered when entering the space, greeting them as they came up the stairs.

In 1998, NMNH conservators determined that the Triceratops mount was in danger of imminent collapse.  After 93 years on on display, damage from vibration and fluctuating climate had taken their toll on the fragile fossils. Furthermore, many of the Triceratops bones had developed what preparators call “pyrite disease.” Vertebrate fossils are often partially composed of pyrite, which oxidates under high humidity. This chemical reaction causes fossils to destabilize and fall apart over time. As any DC resident will tell you, high humidity is inescapable several months out of the year. The result of this accumulated damage was that this scientifically and historically priceless specimen was in need of immediate conservation.

Triceratops at the National Museum of Natural History.

The new NMNH Triceratops mount. Photo by the author.

Preparator Steve Jabo and others disassembled the Triceratops mount and carefully conserved each element. With the exception of the skull and the left humerus, which are on exhibit, all of the bones are now individually stored in the Museum’s collections, where they are safer and more accessible to researchers. In their place, a new replica mount has been on display since 2000. Referred to as “Hatcher”, the new mount is an improvement in several ways. First, the new mount has been adjusted to reflect the correct proportions of the animal. The head has been enlarged to match the rest of the body, and the smaller right humerus has been replaced by a mirror image of the left. The new mount shows visitors what a real Triceratops would have looked like, rather than a disproportionate approximation. Additionally, computer simulations were used to work out a more accurate upright posture for the new mount. None of these changes are meant to belittle the work done by Gilmore and Boss a century ago. Paleontology has come a long way since their day, and they would certainly be thrilled by the advances that have been made. Indeed, it is a tribute to the talents of Gilmore and Boss that this specimen continues to inspire and inform more than a century later.

I’ve written about this Triceratops several times – see Hatcher, Stan, and the Changing Identities of Fossil Mounts, as well as The Triceratops Posture Problem Part 1 and Part 2.

The Nedoceratops

Among the ceratopsid fossils Hatcher (the man) collected in Niobrara County, Wyoming was a fascinating skull that has gone by several different names, the only consistent one being its specimen number, USNM 2412. Although sources conflict over when this specimen was excavated (Gilmore reported 1891, Farke says 1899), it was acquired by the USNM as part of the Marsh collection and put on display in the Arts and Industries Building in 1906.

Nedoceratops on exhibit.

Nedoceratops on exhibit. Source

The skull in question generally resembles Triceratops, but its orbital horns stand nearly straight up, instead of facing forward as in most known Triceratops skulls. It also has strange, asymmetrical fenestrae in its frill, and a round boss instead of the usual nasal horn. Hatcher intended to name this specimen as a unique genus, but he died before completing the monograph on Ceratopsidae that he had, in turn, inherited from Marsh. Paleontologist Richard Lull eventually completed the monograph and named the specimen Diceratops hatcheri. Gilmore disagreed, however, arguing that the specimen’s unique features were most likely pathological. The situation was further complicated by the fact that, in the process of preparing the skull, a large portion of the frill was reconstructed*, which obscured the curious openings on the right side.

*In his 1906 discussion of USNM 2412, Gilmore reports that only the horns were restored. However, more recent studies of the specimen clearly show that the right side of the frill was reconstructed as well. 

Lull’s monograph remained the final word on USNM 2412 until the 1980s, when the debate over whether its abnormalities fell within an acceptable range for Triceratops resurfaced. More recently, Jack Horner and colleagues have proposed that Triceratops and Torosaurus are the same animal, and that this skull represents an intermediate growth stage between the two forms, but this position has been countered by Farke and others. To top it all off, the name “Diceratops” turned out to be preoccupied by a wasp, and had to be replaced with Nedoceratops. Over a century since it was first put on display, there is no consensus on the identity of this skull.


Brinkman, P.D. 2010 The Second Jurassic Dinosaur Rush: Museums and Paleontology in America at the Turn of the 20th Century. Chicago: University of Chicago Press, 2010

“Building a Dinosaur.” Department of Paleobiology, Smithsonian National Museum of Natural History. Accessed July 27, 2012. http://www.mnh.si.edu/highlight/triceratops

Farke, A. 2011 “Anatomy and Taxonomic Status of the Chasmosaurine Ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A.” PLoS ONE, 6:1.

Gilmore, C.W. 1905 “The Mounted Skeleton of Triceratops prorsus.Proceedings of the United States National Museum 29.

Gilmore, C.W. 1906 “Notes on Some Recent Additions to the Exhibition Series of Vertebrate Fossils.” Proceedings of the United States National Museum 30.

Gilmore, C.W. 1941 “A History of the Division of Vertebrate Paleontology in the United States National Museum.” Proceedings of the United States National Museum 90.

Marsh, D.E. (2014). From Extinct Monsters to Deep Time: An ethnography of fossil exhibits production at the Smithsonian’s National Museum of Natural History. http://circle.ubc.ca/handle/2429/50177

Marsh, O.C. 1891 “Restoration of Triceratops.” In The Dinosaur Papers 1676-1906, Weishampel, D.B. and White, N.M., eds. Washington, DC: Smithsonian Books.

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Filed under collections, dinosaurs, exhibits, Extinct Monsters, fossil mounts, history of science, marginocephalians, museums, NMNH, ornithopods, reptiles

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