Category Archives: sauropods

“No progress at all. Rhinos too thick.”

So wrote American Museum of Natural History fossil collector Albert Thomson in his September 1917 field notes. At that point, Thomson been collecting mammal fossils at Agate Springs nearly every year since 1907—and was still finding rhino bones in such abundance that they formed a seemingly impenetrable layer.

Located in northwest Nebraska and dating to about 22 million years ago, the Agate Springs bone bed is an aggregation of fossilized animals on an astonishing scale. Like the Carnegie quarry at Dinosaur National Monument, it provides a snapshot of an ecosystem at a moment in geologic time. But while a high estimate of the individual dinosaurs represented at Carnegie Quarry is in the hundreds, the main bone bed at Agate Springs may well contain tens of thousands of animals. The vast majority of fossils come from the tapir-sized rhino Menoceras, scrambled and packed together in a layer up to two feet thick. Moropus, Daeodon, and an assortment of other hoofed animals and small carnivores have also been found. These animals may have gathered during a drought and succumbed to thirst or disease, before the returning rains rapidly buried their remains. It’s also possible that the bone bed represents a mass drowning during a flash food. Since different parts of the site vary in density, Agate Springs likely represents multiple mortality events over a number of years.

Today, less than 30% of the Agate Springs bone bed has been excavated, but not for a lack of effort. Teams from a half dozen museums visited the site between 1900 and 1925, with the Carnegie Museum of Natural History (CM), the University of Nebraska State Museum (UNSM), and the American Museum of Natural History (AMNH) establishing large-scale excavations and returning year after year. As we shall see, the relationships between these teams were not always amicable, making this period at Agate Springs a window into the preoccupations of museum workers at the turn of the century. Agate Springs also illustrates how east coast paleontologists interacted with and relied on local people, defending their social capital as jealously as any fossil deposit. Finally, museums’ interest in Agate Springs in the mid 20th century exemplifies how exhibitions had evolved during the intervening period.

The setting

Agate Springs is unceded Sioux territory, occupied by settlers after the Kansas-Nebraska Act of 1854. James Cook purchased the treeless tract of rolling hills from his father-in-law in 1887, naming it Agate Springs after the rocky banks of the nearby Niobrara River. James and Kate Cook established a ranch where they raised horses and cattle, and Agate Springs became a popular stop for travelers on their way to Cheyenne, Wyoming.

The Cooks were aware of bones weathering out of the hills as far back as 1885, when the land was still owned by Kate’s father. James knew that scientists were on the lookout for fossils in the region—by one account he worked for O.C. Marsh as a translator in 1874. Once the ranch was established, he began writing to museums, including UNSM in Lincoln and the Carnegie Museum in Pittsburgh, inviting them to visit Agate Springs. A UNSM party led by Erwin Barbour was the first to drop by, spending a night at the Cook homestead in July 1892. Chiefly concerned with collecting “devil’s corkscrews” (ancient beaver burrows) north of the Niobrara, Barbour sent his student F.C. Kenyon to check out the bones Cook promised in the nearby hills. Kenyon collected as much as he could carry, but his report apparently did not excite Barbour, and the UNSM party moved on.

It would be twelve years before another paleontologist visited Agate Springs. Olaf Peterson of the Carnegie Museum stopped by the ranch in early August of 1904, at the end of a tumultuous field season in western Nebraska. Peterson had received a telegram on July 4 that his brother-in-law, boss, and mentor John Bell Hatcher had died of typhoid. Peterson intended to cut the season short, but Carnegie Museum director William Holland denied the request, writing in no uncertain terms that Peterson was to continue his work in Nebraska. Later in July, Peterson fell ill himself, and spent several days recovering in Fort Robinson. Suffice it to say, Peterson was not in the best of moods when he arrived at Agate Springs.

Nevertheless, the outcrops Peterson saw at Agate Springs revitalized his spirit. Accounts differ on what part of the site Cook showed him (this will be important shortly), but when he returned east two weeks later he was raving about a quarry with “ten skulls within a six-foot radius.” In Pittsburgh, Peterson and Holland began drawing up plans for an ambitious excavation the following year. In their view, they had staked a claim to the site: just like contemporary gold and oil prospectors, turn-of-the-century paleontologists lived by the rule of “dibs.” For the museum crowd, being the first scientist to “discover” a quarry meant an entitlement to control the site and the resources it produced. This included both the physical fossils and the privilege to describe and interpret those fossils—controlling the site meant controlling scientific knowledge.

Dueling quarries

Cook either didn’t know about such customs, or didn’t care. To his credit, Cook was never interested in monetizing the fossils at Agate Springs. By all accounts, he simply wanted to share with the world the knowledge that the bone bed represented. He was concerned that it was so expansive that no single team could uncover all its secrets. On May 26, 1905, Cook wrote to Barbour, inviting him to share in the bounty he had shown Peterson the previous summer, explaining that it was “so large that [the Carnegie team] could not work it out in years, so there is plenty of material for other parties to work with.”

On other occasions, Barbour had taken a cautious stance when corresponding with landowners. In this case, however, he could barely contain the enthusiasm in his reply. In a single letter, Barbour reminded Cook that UNSM had visited 12 years before and therefore should have collecting rights, asked Cook to place a literal flag on the site claiming it for the University of Nebraska, offered to hire Cook’s 18 year-old son Harold as a field assistant, and appealed to Cook’s state pride by listing the out-of-state institutions that were removing Nebraska’s fossil heritage each year.

That summer, Peterson and Barbour opened quarries on two neighboring buttes at Agate Springs, which came to be known as Carnegie Hill and University Hill. While the two parties were cordial neighbors, letters exchanged by Holland, Barbour, and Cook demonstrate that the museum directors were uncomfortable with the situation. Holland repeatedly wrote to Cook, claiming that his team was more skilled than Barbour’s and warning that it would be bad for science if the fossils and geological data were split between two institutions. Harold Cook didn’t appreciate Holland’s condescending tone. In a note to his father pinned to one of the letters, he wrote that “a letter of this kind is the work of a pinheaded, egotistical, educated fool.”

The Carnegie and UNSM teams returned to Agate Springs in 1906, but spent the summer of 1907 elsewhere. The elder Cook took the opportunity to invite yet more paleontologists, and teams from AMNH, the Yale Peabody Museum, and Amherst College showed up to collect fossils.

Meanwhile, Holland began a campaign to wrest control of the site by any means necessary. He became particularly focused on the narrative of who discovered the bone bed. According to Holland, Cook had shown Peterson the smaller, less dense site that would be come to be known as Quarry A. Peterson then went prospecting on his own and found the primary bone bed that straddled the two buttes. Holland went on to argue that regardless of who first saw the fossils, Peterson earned credit for the discovery because he was the first trained scientist on the scene, and therefore the first individual to correctly identify the age and identity of the animal remains.

Cook rejected Holland’s retelling of the events of August 1904, insisting that he had known of the bone bed for years before he showed it to Peterson. In many ways, the two men were talking past each other. Cook found Holland’s insistence on claiming the discovery for Peterson nonsensical and disrespectful—he knew his own land, and he was the one who invited the paleontologists in the first place. Holland, on the other hand, was staking a claim among his fellow academics. He needed to demonstrate that the Carnegie Museum had been at Agate Springs first, so that other institutions would yield to his authority to interpret and publish on the fossils.

Late in 1907, Holland visited the Cooks’ ranch in person for the first time. He offered to buy the fossil-bearing land outright, doubtlessly planning to block the other museums from accessing it. At this point, James Cook made the awkward discovery that Carnegie Hill and University Hill were actually just outside his official holdings, in the public domain. Holland moved to purchase the land, but Harold Cook beat him to it, building a cabin and filing a homestead claim in March 1908. In their gentlemanly rancher way, the Cooks told Holland to get lost, and the Carnegie Museum left Agate Springs for good.

Playing nice

While Holland had managed to sour his relationship with a remarkably welcoming and accommodating landowner, Barbour did the opposite. In letters to Cook, he regularly acknowledged the rancher as the discoverer of the site. He visited the Cooks frequently and employed Harold in the UNSM quarry, training the younger Cook into a formidable fossil prospector and anatomist. Soon Harold was studying at the University of Nebraska under Barbour, and a few years later, Harold and Barbour’s daughter Elinor were married. Barbour also named a few species after the Cooks, including Moropus cooki.

AMNH director Henry Osborn and field manager Albert Thomson had a similarly positive relationship with the Cooks. The New York museum took over Carnegie Quarry in 1908, and Osborn visited several times to express his gratitude. Like Barbour, he paid Harold for his time, labor, and expertise. Later, Osborn invited Harold to work at AMNH during the off-season. In return, AMNH was permitted to collect at Agate Springs for nearly two decades. Thomson returned almost every year through 1923, and the museum accumulated so many Menoceras and Moropus fossils that it began selling and trading them to other institutions.

The reward for staying in the Cooks’ good graces was clear. UNSM and AMNH paleontologists gained access to the Agate Spring quarries for many years, accumulating large collections. They earned accolades from publications, public interest from the skeletons they placed on exhibit, and even monetary rewards from selling the excess specimens. Meanwhile, the Carnegie Museum was shut out after their first few seasons of collecting because Holland was, if not outright hostile to the Cooks, unable to communicate effectively with the ranchers. For American paleontologists at the turn of the century, social capital was a critical resource. Positive relationships with landowners and other individuals in the fossil-rich western states earned them access to land, information about the terrain, and networks of eyes on the ground, any of which might lead them to the next important quarry.

You get a rhino block, and you get a rhino block…

The scale and intensity of the Agate Springs excavations decreased after 1910, and in the early 20s, Thompson and the AMNH crew closed up shop, believing they had found examples of every species that could be found. By that time, the site’s value for museums had shifted. Rather than being a bonanza of specimens to collect, categorize, and publish on, Agate Springs had become a place to quickly and easily obtain display-worthy fossils. As Hunt puts it, the site was a “storehouse of good exhibit materials, to be tapped when needed by museums wishing to mount a rhino or two.”

Today, Agate Springs fossils—acquired in the field or via trade—are on display at large and small museums all over North America. Many of these are mounted skeletons of rhinos, camels, and Moropus, but there is also a particular abundance of large, incompletely prepared slabs, which provide viewers with a small window into the Agate Springs bone bed. Because of the sheer density of bones, the early 20th century excavation teams quickly stopped jacketing fossils individually, and instead began preparing out large blocks, typically four to six feet across. The blocks were hardened with shellac, and reinforced with wood planks around their borders. Pulleys and cranes were required to lift the largest blocks out of the quarries. In the early years, the intention was to fully excavate these blocks at their respective museums. It’s not clear which museum first placed a complete block on exhibit, but the idea proved popular. Many later visitors to Agate Springs, from James Gidley of the National Museum of Natural History in 1909 to Elmer Riggs of the Field Museum of Natural History in 1940, came with the express purpose of collecting intact slabs for display.

The popularity of fossil blocks from Agate Springs coincides with a shift in philosophy toward exhibitions at natural history museums. While early 20th century exhibits were catalogs of life, emphasizing the breadth of the museum’s collection, by the 1920s and 30s many museums had begun moving toward narrative exhibits. Displays were intended to communicate ideas, and objects served as illustrations of those ideas. The fossil blocks from Agate Springs were ready-made illustrations of a number of paleontology concepts, from the process of taphonomy to the task of excavation millions of years later. Most have remained on display to this day, a fact that James Cook would undoubtably be pleased with.

An incomplete list of museums in possession of Agate Springs blocks follows. Do you know of others? Please leave a comment!

• Carnegie Museum of Natural History
• American Museum of Natural History
• University of Nebraska State Museum
• Field Museum of Natural History
• National Museum of Natural History
• Royal Ontario Museum
• Yale Peabody Museum of Natural History
• Harvard Museum of Comparative Zoology
• University of Wyoming Geological Museum
• South Dakota School of Mines and Technology
• Wesleyan University Geology Museum
• University of Austin Texas Memorial Museum
• University of Michigan Museum of Natural History
• Science Museum of Minnesota
• Fort Robinson State Park Trailside Museum

References

Agate Fossil Beds: Official National Park Handbook. Washington, DC: National Park Service.

Hunt, R.M. 1984. The Agate Hills: History of Paleontological Excavations, 1904-1925. 

Vetter, J. 2008. Cowboys, Scientists, and Fossils: The Field Site and Local Collaboration in the American West. Isis 99:2:273-303.

Skinner, M.F., Skinner, S.M., Gooris, R.J. 1977. Stratigraphy and Biostratigraphy of Late Cenozoic Deposits in Central Sioux County, Western Nebraska. Bulletin of the American Museum of Natural History 158:5:265-370.

About 150 million years ago, a severe drought ravaged the western interior of North America. In eastern Utah, malnourished dinosaurs gathered near a dwindling river. Unwilling or unable to leave the water source, they eventually died of thirst or disease. When rain finally returned to the region, three or four successive flash floods washed dozens of animal carcasses into a relatively small depositional area to the southeast. Today, this site is known as the Carnegie Quarry at Dinosaur National Monument, and it is one of the most incredible fossil sites in the world.

Today, a structure encompassing a 180-foot section of the deposit (less than half its total length) allows visitors to view nearly 1400 dinosaur bones in situ. However, the fossils on display at Dinosaur National Monument represent only a portion of the material found at the Carnegie Quarry. Between the site’s discovery in 1908 and the establishment of the quarry wall exhibit, more than 20 reasonably complete dinosaur skeletons and dozens more incomplete specimens were excavated and distributed to museums in the US and Canada. No less than eleven mounted skeletons have been created from this material, and they are all still on display today. Although they are thousands of miles from their place of discovery and exhibited in four different cities, these mounts all represent individuals that lived and died in the same environment. They may have even encountered each other in life!

The Discovery

Earl Douglass was already an established fossil hunter when the Carnegie Museum of Natural History hired him in 1902. Late in the 1909 field season, Douglass was prospecting near the confluence of the Green and Yampa Rivers when he spotted a series of sauropod vertebrae eroding out of the rocks. Once Douglass and his crew began excavating the fossils, it became apparent that they had not just one remarkably complete dinosaur, but several. Douglass called it a “beautiful sight,” and CMNH director William Holland could barely contain his glee in his reports back to the Pittsburgh museum. Under Douglass’s management, CMNH crews worked at what became known as the Carnegie Quarry for 13 years. The dinosaur fossils were jumbled and often overlaid one another, so the excavators had to work on multiple skeletons simultaneously. The especially hard sandstone also slowed their work, and the team regularly resorted to huge horse-drawn plows and even dynamite to reach the fossils. Eventually railway tracks were installed to help transport blocks of sandstone out of the quarry.

In 1915, Holland successfully petitioned Woodrow Wilson to preserve the site as a national monument. CMNH crews continued to excavate until early 1923. At that point, their primary benefactor Andrew Carnegie had died, and funding for field work was dwindling. Other museums collected from the quarry periodically in the years that followed, but Douglass’s idea to contain the remaining fossils in an on-site museum was not realized until 1958.

The Mounts

Apatosaurus louisae – CM 3018

The CMNH Apatosaurus was the first dinosaur discovered at the Carnegie Quarry. After Douglass first spotted the articulated caudal vertebrae in August of 1909, his crew spent several months extracting the rest of the skeleton from the rocks. The excavation continued into early 1910, and by the time they were finished they had the most complete Apatosaurus ever found – a title the specimen holds to this day. Holland mounted the 77-foot skeleton alongside the museum’s Diplodocus in just three years, at the time a record for a sauropod mount.

Holland famously left his Apatosaurus headless for decades due to a disagreement with Henry Osborn of the American Museum of Natural History. Douglass recovered a skull that almost certainly belonged to the Apatosaurus, but Holland opted not to use it because it contradicted the sculpted head already in place on the AMNH Apatosaurus mount. After Holland’s death in 1932, museum staff quietly added a casted Camarasaurus skull as a placeholder. This was finally replaced with a proper Apatosaurus skull in 1979. More recently, the team at Phil Fraley Productions disassembled and restored the Apatosaurus, along with the rest of the classic CMNH dinosaurs. Since 2007, this specimen has been back on display in a more graceful modern pose.

Barosaurus lentus – AMNH 6341

When the CMNH team discovered this skeleton in 1912, they assumed it was yet another specimen of the well-known Diplodocus. It was harvested for parts, with portions sent to CMNH, the United States National Museum, and the University of Utah to supplement their displays. When the specimen turned out to be the more obscure sauropod Barosaurus, it languished in pieces for many years. Barnum Brown of AMNH was making a circuit of the fossil collections at various natural history museums when he rediscovered this specimen. Through a series of purchases and trades, the Barosaurus was reunited at AMNH in 1929.

Nevertheless, AMNH quickly abandoned plans to mount the Barosaurus – the museum already had a sauropod on display, and there wasn’t enough floor space for another one. It wouldn’t go on display until 1991, when Lowell Dingus conceived of the idea to mount the Barosaurus in a spectacular rearing pose as part of the renovation of the Theodore Roosevelt Rotunda. Peter May took on the project – one of the first mounts produced by his company Research Casting International. The resulting display, actually a cast, is the tallest free-standing dinosaur mount in the world.

Barosaurus lentus – ROM 3670

Douglass recovered a second partial Barosaurus skeleton in 1912, which consisted of a mostly complete torso and parts of each leg. It stayed in the CMNH collections for many years, until they traded it to the Royal Ontario Museum in 1962. ROM staff intended to mount the skeleton, but once again this was cancelled due to a lack of space. David Evans was developing a new ROM paleontology exhibit in 2007 when he learned that the museum had most of a Barosaurus sitting in its collections. With only weeks remaining before the exhibit’s opening, Evans tapped Research Casting International to mount the sauropod, supplemented with a replica neck and tail from the AMNH version.

Allosaurus fragilis – CM 11844

Several Allosaurus specimens are known from the Carnegie Quarry, but the one on display at CMNH is one of the largest. Douglass and his team excavated this 35-foot skeleton between 1913 and 1915. The mount was built in 1938. Although the specimen included a partial skull, the exhibit team swapped it with a cast of a more complete skull (also found in the Carnegie Quarry) from the collections of the University of Utah. This mount also includes casts of the arms of USNM 4734, an Allosaurus collected for O.C. Marsh.

Stegosaurus ungulatus – CM 11341

The CMNH Stegosaurus is a composite of several individuals excavated from the Carnegie Quarry between 1920 and 1922. Museum staff completed the 21 foot-long mount in 1940, using a skull cast from USNM 8612. Casts of this skeleton were distributed to several other museums at some point, one of which is on display at the University of Nebraska State Museum. Phil Fraley’s company remounted the CMNH original in 2007.

Camarasaurus lentus – CM 11338

This juvenile Camarasaurus is the most complete sauropod ever found. It is displayed as a relief mount almost exactly as it was discovered, with two exceptions. The left leg was swapped with a more complete one from another individual, and the tail was re-positioned to create a more aesthetically pleasing mount. Casts of this skeleton are displayed at museums throughout the United States, including Dinosaur National Monument, but the original is at CMNH. This specimen is also notable because its left scapula is preserved in its life position, making it a helpful model for skeletal reconstructions and exhibit mounts.

Camarasaurus lentus – USNM 13786

The second best Camarasaurus also comes from Carnegie Quarry, but it is a considerably larger individual. Only the tail and a few odds and ends were missing. CMNH kept the specimen for several years before trading it to USNM in 1933 for a set of Pliocene horse skeletons. Norman Boss prepared the specimen in full view of the public during the 1936 Texas Centennial Exposition – one of the first known examples of such an exhibit. The completed mount appeared at USNM in the 1950s, sporting the tail of another Camarasaurus. At over 30 feet long, this skeleton is one of the largest dinosaurs on display at the Smithsonian. Unfortunately, the death pose somewhat limits the effect. The Camarasaurus was taken off exhibit in late 2014 for conservation and remounting. When it returns, it will be standing on its feet for the first time in 150 million years, taking its rightful place as one of the museum’s most impressive dinosaurs.

Diplodocus longus – DMNH 1494

Since this Dipldodocus was found somewhat disarticulated, Douglass suggested that the carcass may have been twisted apart while rolling downstream. AMNH held on to this skeleton for some time before trading it to the Denver Museum of Nature and Science in 1936 for two mammoth skeletons. Preparator Phillip Reinheimer mounted the skeleton with the help of 40 workers assigned to the museum through the Works Progress Administration. Additional Diplodocus fossils collected by William DeWeese (actually the first dinosaur specimens acquired by the museum) were also used to complete the mount. The Diplodocus remained on view until 1989, when Ken Carpenter and others restored and remounted the sauropod, elevating its tail and making its neck sweep gracefully to the left. The improved mount has been on display since 1995.

Camptosaurus aphanoecetes – CM 11337

Douglass found this controversial small ornithopod in 1922, and correctly matched it with an isolated leg several feet away. It was first identified as Camptosaurus medius, but in 2008 Ken Carpenter reassigned it to the new species C. aphanoecetes. A 2011 phylogenic study by Andrew McDonald moved this specimen to a new genus, Uteodon. Carpenter, however, asserts that McDonald’s analysis was based on an incorrectly associated Dryosaurus braincase.

CMNH staff assembled the fossils into a relief mount in 1940. The skull, hindfeet, and tail were all sculpted. During the 2007 renovation, the Phil Fraley Productions team extracted the fossils from the plaster slab, even managing to preserve the delicate ossified dorsal tendons. They then created a new, three-dimensional mount, which features a revised replica skull.

Dryosaurus altus – CM 3392

This Dryosaurus skeleton is the most complete of several collected at Dinosaur National Monument. The tail is missing, and given the completeness of the rest of the skeleton it may well have been destroyed when Douglass’s crew was blasting through rock to get to the bone layer. The Dryosaurus entered the CMNH collections in 1922, and was assembled as a 9 foot-long relief mount in 1940. In 2007, Fraley’s team removed the fossils from the plaster matrix, and just as they did with the Camptosaurus, constructed a standing mount. To date, this is the only mounted Dryosaurus specimen in the world. It is displayed alongside a juvenile Ceratosaurus cast acquired from Western Paleontological Laboratories.

Diplodocus sp. – USNM 10865

The National Museum of Natural History’s Diplodocus was one of the last articulated skeletons removed from the Carnegie Quarry. When the CMNH crew closed up shop, Charles Gilmore of the Smithsonian moved in to recover one of the sauropod skeletons Douglass left behind. In 1923, Gilmore’s team excavated a partial Diplodocus, and also cherry-picked a few extra bones from an adjacent specimen. The process of mounting the skeleton at USNM took six years of continuous work, and Gilmore would later describe it as the most ambitious undertaking his department hadever attempted. The 70-foot Diplodocus mount was completed in 1931, and remained unchanged for more than 80 years. It was finally taken down in December 2014, and will return in a new pose in 2019.

Addendum: Mike Taylor recently called attention to a gorgeous map of the entire deposit prepared by Ken Carpenter, which was what prompted this post. Check it out here.

References

Carpenter, K. (2013). History, Sedimentology, and Taphonomy of the Carnegie Quarry, Dinosaur National Monument, Utah. Annals of the Carnegie Museum 81:3:153-232.

Dingus, L. (1996). Next of Kin: Great Fossils at the American Museum of Natural History. New York, NY: Rizzoli International Publications, Inc.

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.

McGinnis, H.J. (1982). Carnegie’s Dinosaurs: A Comprehensive Guide to Dinosaur Hall at Carnegie Museum of Natural History, Carnegie Institute. Pittsburgh, PA: The Board of Trustees, Carnegie Institute.