SC building to feature Allosaurus found near Poison Creek
Date posted: March 16, 2013
SHERIDAN — When the new Whitney Building at Sheridan College opens this summer, visitors will be greeted by a full-size mount of an Allosaurus dinosaur named Caesar, excavated by Sheridan College students and community volunteers.
Caesar’s journey to campus began in the late Jurassic period when he died in or near a river and his bones were eventually buried and preserved under sediment.
One hundred fifty million years or so later, in the early 1990s, some of his bones were found in Johnson County on a section of state land.
The quarry site near Poison Creek where Caesar was found, was initially excavated by students and volunteers from the Science Museum of Minnesota in St. Paul. However, in 1989, the lead researcher approached Mike Flynn, saying that the museum could not afford to continue coming out for excavation and encouraged Flynn to apply for the fossil permit and take over excavation work.
Flynn applied to the Wyoming State Land Board for the fossil permit and received it in 1990.
“We started a new quarry close by, about 1,000 meters down the slope from where St. Paul was,” explained Flynn, who taught geology and paleontology at Sheridan College for 27 years. “It started out as an educational and collection site where I would bring my geology and paleontology students.”
Shortly after beginning work, he noticed bones sticking out from an eroded area of sandstone.
“I knew they were metatarsals and I could tell they were anklebones,” Flynn said. “I didn’t want to remove them right away. I didn’t want to remove that teaching site, it was so excellent.”
Instead, Flynn used the site to point out to his students the bones and their features, as well as geologic features of the surrounding area for the next four years.
“There is a paleo-river there, meaning ‘ancient river,’ and the dinosaur carcasses would disarticulate in the banks of this river,” Flynn said. “I could tell the banks and center of the river by the geology. Caesar was mainly in the center of a channel sand.”
In 1994, official excavation of Caesar began and as more of his bones were uncovered, it became clear he was an Allosaurus. Students and community volunteers worked on the project for several years during the field season of early May to early October.
“The Allosaur is a medium sized dinosaur, not as big as T-rex but not as small as a Velociraptor. It is Wyoming’s most common carnivore and it is still not very common,” said Flynn, noting that carnivorous dinosaurs are outnumbered by herbivores about 100 to one. “It is the only carnivore in 30 years of working with fossils that I have come across.”
One of the primary workers on the project was paleontologist Bill Matteson, a student of Flynn’s. Though he eventually went on to the University of Wyoming for further education, Matteson returned during the summers to work at the site and helped establish the Sheridan College Science Museum. He is now a part-time staff member at the college.
It was Matteson who discovered that much of Caesar actually lay on private land adjoining the state section.
“In 2008, I went up there and was doing the map, making a map of where the bones came out of,” Matteson said. “I took some GPS units and plugged them into Google Earth and discovered the fossil was about 300 feet into private land belonging to Skey Johnston.
“So once we discovered that, I got together with Mike and we went to the land manager and said ‘this is the situation, do you think he would be willing to donate it to the college?’ and he did.”
While Caesar is approximately 40 percent complete, Flynn said other dinosaurs found in the area are only about 10 percent complete.
The full-size mount in the Whitney Building will be made of molds taken from casts of the original bones. The actual skull bones from Caesar will also be on display near the mount.
Casts will be taken from Caesar’s bones, as well as from bones from another Allosaurus found on the other side of the Bighorns near Shell, from a specimen nicknamed Big Al. Big Al is likely the most compete Allosaurus ever found, at 95 percent complete.
“We have representations of almost all the bones of the body, except we are missing the neck and the spine,” explained Matteson, about which bones have been found of Caesar. “We have most of the tail, but that is really the only thing that is significantly missing.”
“The way it will work is we will have the full skeleton on display and the reconstructed actual skull,” he continued. “For research purposes the rest of the bones will be locked away in fire proof cabinets and they won’t be exposed.”
Matteson estimates the mount will be eight feet tall and 25 feet long when complete. He said it is unknown if Caesar was a male or a female, but they do speculate that the specimen was not full-grown at the time of death. Matteson said it is possible Caesar weighed 3,000 pounds or more.
“Allosaurs actually are the most common predator of that time period,” Matteson said. “They’ve found quite a few of them. The most famous representations are in Utah. There was a quarry there where they dug up a whole bunch of them. In Wyoming they do turn up somewhat regularly. Big Al is the most famous and Big Al 2. They were the most complete ones ever found in Wyoming. I don’t know this for a fact, but Caesar may be the third most complete. I haven’t heard of one more so.”