Plesiosaur Stomach Stone Found During Student’s Field Trip
RAPID CITY, S.D. (AP) — Grabbing a small glass tube, South Dakota School of Mines and Technology graduate student Reid Cummins poured out what looked like an ordinary stone and said it was his favorite find from his summer field project.
It was a gastrolith, a paleontologist’s dream, about the size of a small marble, and he recently displayed it in his hand in the Mines’ paleontology laboratory, its blackness contrasting sharply against the flesh color of his palm.
Not only was the stone fairly rare for the area, but it also holds the possibility of preserving for future searches the land where it was found.
At the Wallace Ranch Paleontological Special Interest Area in Fall River County, Cummins and 14 volunteers searched for fossils for five days in mid-July.
Among his finds was the gastrolith, a stomach stone from a plesiosaur, a marine reptile with a long neck, long tail and paddles, from about 70 million to 80 million years ago, Cummins said. The instant he saw it, he knew he had an exciting discovery.
While that area is rich in fossils, the plesiosaur’s stomach stone was only the second or third to be found there, said Barb Beasley, a U.S. Forest Service paleontologist.
Beasley worked with Cummins this summer to complete the project he is using for his thesis. She is hoping his research will lead to further education and will help to protect sites like the one they searched.
“It’s a special interest area,” she said. “This will help people learn something about the area and what can be found there and preserve it. If artifacts aren’t collected properly, there’s no redoing it.”
The reptiles ingested gastroliths to help with digestion and to break up food in their stomachs, the Rapid City Journal ( ) reported. One animal could have swallowed hundreds of stones.
Volcanic ash fell through the Western Interior Sea, in the area in Fall River County, and Cummins wanted to know if that ash affected the marine animals.
The area had six volcanic ash falls during the time of the depositing of the Pierre Shale at the particular site, according to a release from the U.S. Forest Service.
The area also accommodated Cummins’ needs, Beasley said. Cummins has a condition called dwarfism — he stands 3 feet, 1 inch tall — that limits his mobility and ability to perform a significant amount of field work needed to complete requirements for his degree.
A paleontology major, Cummins’ goal this summer was to gather data for his study of animals and specimens.
What he liked so much about the stomach stone was that it provides a look at more than just the animal’s body and bones.
“I work with fossils a lot, and this wasn’t just the animal, it’s something that relates to its life and its behavior,” Cummins said. “I’m fascinated by ancient life and learning about it.”
The stone wasn’t his only find. He also brought back a dozen other fossils that included fragments of flying fish-eating reptiles, fossil fragments from two turtles, and shark teeth. The quality and quantity of the fossils meant his effort was a huge success.
To finish his thesis, Cummins will continue to analyze the data using equations and graph to eventually write the report.
Examples of the reptiles Cummins found fragments from can be seen in the Museum of Geology on the Mines campus, including a full-size plesiosaur. Cummins double majored in biology and geology for his undergraduate degree.
After graduation, Cummins said, he hopes to work in a museum. His goal is to have his thesis, which he has been working on for about two years, completed by the end of the school year. Attempts to conduct the same research last year were halted because of so much rain.
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Information from: Rapid City Journal,
