I am co-authoring a manuscript that, among other things, tries to trace the history of the molds made by the Carnegie Museum in the early 1900s, from which they cast numerous replica skeletons of the Diplodocus carnegii mount (CM 84, CM 94, CM 307 and other contributing specimens). This turns out to be quite a mystery, and I have become fascinated by it.

Below is the relevant section of the manuscript as it now stands. Can anyone out there shed any further light on the mystery?

So far as we have been able to determine, the casting of the concrete Diplodocus of Vernal was probably the last time the Carnegie Museum’s original molds were used. However, that was not Untermann’s intention. In his 1959 account, he wrote (p368–369):

Several museums in the United States and from lands as distant as Japan and Italy have expressed a desire to acquire the molds and cast a Diplodocus of their own from either plaster or some of the newer synthetics. To date no museum has apparently been able to make satisfactory arrangement for the acquisition of the molds and the casting of a skeleton. We still have the molds in Vernal, and any museum, anywhere, is welcome to them just for hauling them off. […] The Diplodocus on the lawn of the Utah Field House is the eleventh replica to be cast from the molds […] Does anyone wish to cast the twelfth?

From here, though, the story becomes contradictory. Sassaman (1988) reported that “the molds finally fell apart because of old age soon after it [the concrete Diplodocus] was made”. Similarly, Ilja Niewland (pers. comm., 2022) said that “The original moulds were thrown away somewhere during the 1960s (nobody at the [Carnegie Museum] could be more specific than that)”, suggesting that the molds may have been returned to their origin.

Both these accounts seem to be in error, as shown by a 1960 report in the Vernal Express newspaper (Anonymous 1960a; Figure H; see also Carr and Hansen 2005). This says that in the middle of July 1960, the molds were collected by the Rocky Mount Children’s Museum (now the Rocky Mount Imperial Center, Children’s Museum & Science Centre) in North Carolina, with the intention that they would be used to create a twelfth cast which would be mounted outside the museum building next to the Tar River in Rocky Mount’s Sunset Park. But was such a cast ever created? A sequence of reports in the Rocky Mount Evening Telegram from April to July 1960 (Williams 1960, Bell 1960a, Bell 1960b, Anonymous 1960b) enthusiastically announce and discuss the impeding arrival, and the later articles say that museum board president Harold Minges has left for Utah to collect to molds — but then the newspaper goes silent on the subject, and the project is never mentioned again. There is no positive evidence that the molds even arrived in Rocky Mount, far less that they were used to create a new mount. Thus newspaper reports from both Utah and North Carolina say that the molds set out on their journey from one to the other, but neither confirms that they ever arrived. On the other hand, there is also no report of the molds being lost or destroyed, so perhaps the most likely interpretation is that they arrived in Rocky Mount, but were found to be in worse condition than expected and quietly left in storage. This interpretation is supported by Rea (2001:210) who reported that “from Vernal the molds kept travelling — first, to the Rocky Mount Children’s Museum in Rocky Mount, North Carolina, although a cast was never made there”. Similarly, Moore (2014:234-235) stated that “From Vernal, Utah, [CM] molds of Diplodocus carnegii are shipped to Rocky Mount Children’s Museum in Rocky Mount, North Carolina. Because of the age-related damage to the molds, a cast was never prepared”.

Hurricane Floyd devastated Rocky Mount in 1999, with flooding from the River Tar destroying the original Children’s Museum along with all its exhibits and records (Leigh White, pers. comm., 2022), so no records survive that could confirm the molds’ arrival or any subsequent use. The museum was located next door to a municipal water treatment facility that also flooded and released unknown chemicals, so museum property that might have otherwise been salvageable in that area was deemed contaminated and required to be destroyed. If the molds were in storage at the Children’s Museum at this time, then this was likely the end of their story.

The Children’s Museum was re-established at the newly built Imperial Centre, where it still resides, but no trace exists there of molds or casts of Diplodocus. Corroborating the hypothesis that no cast ever existed, most staff who worked at the museum in the 1980s do not recall any such cast (Leigh White, pers. comm., 2022). Contradicting this, however, Jan Engle Hicks, Curator of Education at the Rocky Mount Children’s Museum from 1971–2002, has a memory of Diplodocus casts being on exhibit at the museum when she started work in 1971. She does not recall if they were still part of the museum collection in 1999 when the collection was destroyed.

Whether or not a cast was made at Rocky Mount, it is possible that this was not the end for the molds. Rea (2001:210) continues: “Eventually the molds found their way to the Houston Museum of Science, where they were used to fill in gaps in the Diplodocus hayi skeleton that had been swapped from Pittsburgh to Cleveland before ending up in Houston”, citing a personal communication from John S. McIntosh. (The skeleton in question is that of CM 662, which became CMNH 10670 in Cleveland, then HMNS 175 in Houston. Having been nominated as the holotype of the new species Diplodocus hayi by Holland (1924:399), the species was later moved to its own new genus Galeamopus by Tschopp et al. (2015:267).)

Due to the loss of the Rocky Mount Children’s Museum records, we cannot tell whether they ever shipped the molds to Houston; and we have not been able to obtain information from the Houston Museum. Brian Curtice (pers. comm., 2022) reports that he was in Houston in 1995 and did not see the molds in the collection, nor hear of their ever having been there. In the absence of evidence that the molds ever made it to Houston, it seems at least equally likely that the missing bones in HMNS 175 were cast and supplied by Dinolab, using the second-generation molds described blow, and that Rea (2001) misreported this.

As recently as 1988, Rolfe (1988) wrote on behalf of the Royal Museum of Scotland, “At present I am exploring the possibility of re-using the Carnegie Museum, Pittsburgh moulds, although there is considerable doubt about whether they are up to the job, after so much previous use”. Sadly, his letter does not mention their then-current whereabouts.

In an unpublished manuscript, Madsen (1990:4) wrote that “The fate of the initial set of molds is somewhat in question, but Wann Langston (personal communication, 1989) suggests that they seem to have been lost, strayed, or stolen during transport from ? to ?. Principles contacted in regards to the disposition of the molds could not provide specific information.”. Infuriatingly, the question marks are in the original. Since both Langston and Madsen are now deceased, there is no way to discover on which of the molds’ journeys Langston thought they were lost or destroyed. It is unlikely, at least, that Langston had in mind the their initial journey from Vernal to Rocky Mount. Kirby (1998:4) wrote that “Somewhere along the line, as the story goes, the molds received from the Carnegie had been shipped to a school down south and never arrived. So they were lost”. Since Rocky mount is about 2000 miles east (not south) of Vernal, “a school down south” could not have referred, in a Utah publication, to a museum out east. The Houston museum also does not seems an especially likely candidate for this designation, being 1300 miles southeast of Vernal.

Putting it all together, there is no way that all the reports cited here can be accurate. Perhaps the most likely scenario is this: the molds were successfully shipped to Rocky Mount in July 1960 (Anonymous 1960a, Anonymous 1960b) but found to be unusable (Rea 2001:210, Moore 2014:234-235) and left in storage. At some later point there were shipped to a school in a southern state (Kirby 1998:4) but did not arrive (Langston cited in Madsen 1990:4). This may have happened in late 1988 or early 1989, between Rolfe’s (1988) letter that expressed an interest in using the molds and Langston’s personal communication to Madsen in 1989. Where the molds are now, and why they did not arrive, we can only speculate. As Madsen (1990:4) concluded, “It is truly a mystery that an estimated 3–6 tons of plaster molds could simply vanish!”


Anonymous. 1960a. Dinosaur molds take long ride to No. Carolina children’s home. Vernal Express, 14 July 1960, page 15. https://newspapers.lib.utah.edu/ark:/87278/s6zk6w6s/21338221

Anonymous. 1960b. Something ‘big’ for a fact. Rocky Mount Evening Telegram, 8 July 1960, page 4A. https://newspaperarchive.com/rocky-mount-evening-telegram-jul-08-1960-p-4/

Bell, Mae. 1960a. Dinosaur’s coming here brings questions galore. Rocky Mount Evening Telegram, 14 May 1960, page 2. https://newspaperarchive.com/rocky-mount-evening-telegram-may-14-1960-p-2/

Bell, Mae. 1960b. ‘Dinosaur’ soon to arrive here. Rocky Mount Evening Telegram, 3 July 1960, page 3A. https://newspaperarchive.com/rocky-mount-evening-telegram-jul-08-1960-p-8/

Carr, Elaine, and Aric Hansen. 2005. William Randolf Turnage, Dee Hall, and Ernest Untermann [archive photograph with metadata]. University of Utah, J. Willard Marriott Digital Library, image 1086142. https://collections.lib.utah.edu/details?id=1086142

Holland, William J. 1924. The skull of Diplodocus. Memoirs of the Carnegie Museum 9(3):379–403.

Kirby, Robert. 1998. Danny and the dinosaurs. Chamber Spirit (newsletter of the Vernal area Chamber of Commerce) 3(4):1–6.

Madsen, James H. 1990. Diplodocus carnegiei: Production and design of replica skeletons. Unpublished draft manuscript. (No author is named in the manuscript, but Madsen’s son Chris believes it is his work.)

Moore, Randy. 2014. Dinosaurs by the Decades: A Chronology of the Dinosaur in Science and Popular Culture. Greenwood, Westport, Connecticut.

Rea, Tom. 2001. Bone Wars: The Excavation and Celebrity of Andrew Carnegie’s Dinosaur. University of Pittsburgh Press, Pittsburgh, PA.

Rolfe, William D. I. 1988. Untitled letter to LuRae Caldwell (Utah Field House). 24 October 1988.

Sassaman, Richard. 1988. Carnegie had a dinosaur too. American Heritage 39(2):72–73.

Tschopp, Emanuel, Octávio Mateus and Roger B. J. Benson. 2015. A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda). PeerJ 2:e857. doi:10.7717/peerj.857

Untermann, G. Ernest. 1959. A replica of Diplodocus. Curator 2(4):364–369. doi:10.1111/j.2151-6952.1959.tb00520.x

Williams, Oliver. Pre-historic dinosaur to tower over city; giant animal four times taller than man. Rocky Mount Evening Telegram, 24 April 1960, page 3B. https://newspaperarchive.com/rocky-mount-evening-telegram-apr-24-1960-p-11/