A plethora of paleontological discoveries continues to shed light on the world of Converse County 67 million years ago.
Most of that light is coming from everyday people, working day and night, fulfilling their lifelong dreams to dig for dinosaurs.
The Triceratops Gulch Project has been collecting every scrap of fossil from the hills north of Glenrock for decades.
Every gar scale, crocodile scute and stomach acid-etched dinosaur tooth is a piece from a dynamic ecosystem being slowly and meticulously reconstructed to reveal life in Late Cretaceous Glenrock.
People from across the country and all walks of life eagerly flock to Glenrock to simmer in the summer sun while delicately digging into the soft layers of mudstone and sandstone.
And, once the sun goes down, they put on headlamps and keep digging.
“We try to make the most of everyone's time here,” said Matt Mossbrucker, the director of the Morrison Museum of Natural History in Colorado. “One of the ways we extend our time is by using lanterns and headlamps to give people the chance to collect at night.”
Dusk on a September evening at Triceratops Gulch near Glenrock. The ongoing Triceratops Gulch Project, which collects fossils from the 67-million-year-old Lance Formation, is a collaboration between the Glenrock Paleon Museum and the Morrison Museum of Natural History in Morrison, Colorado. (Andrew Rossi, Cowboy State Daily) 
The tiny radius of a Late Cretaceous mammal, found at "Stuart's Site," one of 70 sites being explored and excavated as part of the Glenrock Paleon Museum's Triceratop Gulch Project. (Andrew Rossi, Cowboy State Daily) 
Diggers stretched out across the 33-foot expanse of "Stuart's Site" at Triceratops Gulch. The site only has three feet of exposed sandstone from the Lance Formation, but it contains hundreds of microfossils and some large fossils from the denizens of Late Cretaceous Wyoming. (Andrew Rossi, Cowboy State Daily) 
Amy Toth, an entomologist from Iowa, hands her custom-built family violin to professional musician Alanna North during the "dig by dark" at Triceratops Gulch near Glenrock. (Andrew Rossi, Cowboy State Daily) 
Dinosaur diggers work by lantern light at Triceratops Gulch near Glenrock. To maximize the on-site, down-and-dirty experience for participants, summer excavations extend into the evening, so the search for turtle shell, Triceratops ribs, and T.rex teeth can continue. (Andrew Rossi, Cowboy State Daily)
Digging In The Dark
The final dig of the Triceratops Gulch Project's 2025 season was held from Sept. 11 through Sept. 14.
In addition to staff and volunteers from the Glenrock Paleon Museum and the Morrison Museum of Natural History, the participants included two NASA engineers, an entomologist, a father-son duo on their annual “fishing trip,” and a professional violinist.
Most dinosaur digs wrap things up before the sun sets, but not in Glenrock. After an evening break for dinner, anyone who wants to find more fossils is encouraged to return to Triceratops Gulch and dig in the dark.
“People are coming out to run rock from both coasts of this country and everywhere in between,” Mossbrucker said. “We want to make sure that we're giving them as much time as possible in the field.”
Nobody’s obligated to dig dinosaurs after dark, but most people eagerly accept the unique opportunity.
Once the convoy of vehicles reaches the spot, headlamps are distributed and used to light the path back to the same spots they worked in the sunlight.
The headlamps and lanterns are a bright beacon in the deep darkness halfway down the hillside. It makes the telltale glimmer of enamel on the teeth of Tyrannosaurus, Triceratops, and other denizens of the Late Cretaceous gleam that much brighter.
Amy Toth, an entomologist and professor at Iowa State University, has been digging day and night with her sons Felix, 17, and Leo, 13, for the last five summers. For them, digging by lantern light in Glenrock beats anything they’d do on a Disneyland vacation.
“There's always more to discover and learn here,” she said. “We get to meet a whole bunch of new creatures that you didn't know existed, and it’s a nice way to bond with my sons. It’s educational, and we’re working together.”
The gulch can get chilly after sunset in September, but nobody was deterred by the drop in temperature. And at the peak of summer, it’s a great way to beat the heat.
“In the middle of summer, it's a nice way to end the day,” Mossbrucker said. “When it gets hot, it’s quite pleasant to cool off under the stars.”
Collecting Cretaceous Glenrock
The Triceratops Gulch Project is a citizen-science project collecting fossils from over 70 sites on a ranch near Glenrock. Fossils have been collected from this ranch for 30 years, with plenty of untapped potential waiting to be unearthed.
Mossbrucker is the on-site authority during the multiple digs offered during the summer. Stationed under a small tent, perched on the hillside, he identifies and inventories every fossil uncovered from the site where the participants are working.
Even with the tiniest fragments, Mossbrucker can identify every tooth, scute, bone, and shell fragment down to the species. He can even tell when a tooth’s been swallowed and defecated out by its owner.
This session, everyone was working at “Stuart’s Site,” a 33-foot-long exposure named after Stuart McCrary, president of the Paleon’s board.
The site is unique because it preserves large bones in addition to an abundance of microfossils from fish, lizards, turtles, mammals, and dinosaurs of all ages, sizes, and diets.
“Our area is understudied,” Mossbrucker said. “We’re working in the Lance Formation of Converse County, which captures the last thriving dinosaur-dominant ecosystem in North America. What we're trying to understand, with the number of fossils that have been found out here going back 30 years, is what these dinosaurs were doing in Glenrock. What was living alongside them? What did Cretaceous Glenrock look like?”
The site has four distinct “zones” that Mossbrucker is careful to treat as different sites within the larger site. There are only three feet of rock exposed, but the rock in each zone is different, which indicates changes in the ecosystem.
“It's a pretty wet and lush environment that transitions from small creeks to a lake and to several small ponds,” he said. “Those spots captured not just all the little creatures that are calling this area home, but the exact habitats they occupied.”
One zone had been of great interest this season because of the surprising abundance of teeth from two rare Late Cretaceous dinosaurs: the armored Denversaurus and a small Velociraptor-esque carnivore called Pectinodon.
A nearly complete skeleton of a Denversaurus, called “Lord Clive,” has been excavated from another site nearby. The teeth collected from Stuart’s Site provide more insight into the lifestyle of this rare and massive herbivore.
“Denversaurus is an exceptionally rare dinosaur,” he said. “Finding this many teeth in these zones suggests this was a feeding habitat for this particular animal.”
Dusk on a September evening at Triceratops Gulch near Glenrock. The ongoing Triceratops Gulch Project, which collects fossils from the 67-million-year-old Lance Formation, is a collaboration between the Glenrock Paleon Museum and the Morrison Museum of Natural History in Morrison, Colorado. (Andrew Rossi, Cowboy State Daily) 
The evening excavations at Triceratops Gulch. (Andrew Rossi, Cowboy State Daily) 
Professional musician Alanna North performs atop a large sandstone boulder at Triceratops Gulch near Glenrock. This was North's first dinosaur excavation and first visit to Wyoming, showcasing her unique talents while fulfilling her lifelong dream to dig for dinosaur fossils. (Andrew Rossi, Cowboy State Daily) 
A series of dinosaur tracks exposed on the side of a ravine near Glenrock. Tracks like these are one of the thousands of fossils that have been discovered as part of the Glenrock Paleon Museum's Triceratops Gulch Project. (Andrew Rossi, Cowboy State Daily) 
The skull of "Lady Stephanie," a Triceratops from the Late Cretaceous of Converse County. This skull is one of tens of thousands of fossils recovered from a ranch just outside of Glenrock that is helping to piece together the prehistoric ecosystem during the last days of the dinosaurs. (Andrew Rossi, Cowboy State Daily)
Diverse Perspectives
Just as the water flowed 67 million years ago, conversations flowed easily throughout Stuart’s Site as the dig progressed. Everyone brought a unique background to the dinosaur dig.
The Toths are all “dino-nerds,” but their expertise in entomology has come in handy on multiple occasions.
“One year, we were finding little things that looked like seedpods,” she said. “My son, Felix, said, ‘I think those are ant heads,’ and he was right. We added our own perspective, which was really fun.”
Mossbrucker said everyone who’s descending into Triceratops Gulch has contributed to a dynamic paleontological project.
Tens of thousands of fossils have been catalogued into the Paleon’s collection, which would have taken decades given the limitations imposed on the museum’s volunteers.
“Everybody has their own motivations, but when you put them together, we have this wonderful cumulative effort,” he said. “It’s like reconstructing a crime scene.”
There’s a wide range of experience on-site. Triceratops Gulch has attracted everyone from professional paleontologists like Mossbrucker, perennial amateurs like the Toths, students seeking more field and research experience, and people fulfilling a lifelong dream of digging for dinosaurs for the first time.
“We have a father-son duo, a psychologist and evolutionary biologist, who’ve been coming out together for nine years,” Mossbrucker said. “Collecting fossils in Glenrock has become their family tradition. They call it their ‘fishing trip.’”
Mossbrucker has dozens of potential research papers waiting to be written from what’s already been uncovered at Triceratops Gulch, but he’s playing the long game.
Every season provides more fossils to back up the discoveries being prepared for publication.
“I don't like to rush to publish,” he said. “There are certainly publishable things from these sites, but each of them is interesting enough that if I collect a little bit of a bigger data set, the science will be more impactful.”
Classically Cretaceous
One of the participants on the final dig of the season was Alanna North, a self-proclaimed “dinosaur fanatic” who’s pursuing a Doctor of Musical Arts at the University of Memphis. This was her first dinosaur dig and visit to Wyoming.
“I’ve always been interested in dinosaurs and the fossil record,” she told Cowboy State Daily. “I love the creatures that have endured.”
North, who’s been playing violin since she was 10, didn’t bring an instrument with her. By sheer coincidence, the Toths did.
“We have a violin made by Matthew Gresh, a geologist in Iowa,” Amy said. “Leo’s been playing for about five years and is supposed to be practicing, so we decided to bring the violin with us.”
With an instrument in hand, North put on a “Classical Cretaceous” concert during the night dig at Triceratops Gulch. Perched on a large sandstone boulder, she played pieces by Mozart, Mendelssohn, and Brahms from memory while everyone else dug in the dark.
The undeniable highlight of North's concert was when she played the iconic theme from “Jurassic Park” composed by John Williams.
Plenty of dinosaur digs will play music from “Jurassic Park” from phones and Bluetooth speakers. Getting a live concert from a professional musician, standing on the same spot where dinosaur fossils are being unearthed, is probably a first for any paleontological dig.
North’s big discovery was a tooth, identified as a premaxillary tooth from the snout of an adult Nanotyrannus.
The status of Nanotyrannus is controversial, but the ongoing work at Triceratops Gulch has convinced Mossbrucker of its validity, and he’s confident that three decades of digging at Triceratops Gulch have provided more than enough fossil evidence to prove it.
“It’s the easiest tooth to identify, and it would be dishonest to say it’s anything else,” he said, much to North’s amazement and enthusiasm.
They’ll Be Back
At the end of the three-day dig, all the exposed fossils at “Stuart’s Site” were covered in aluminum foil, while two immense tarps covered the entire site.
Then, several tons of dirt removed from the site over the summer were used to cover the tarps, protecting the site for the winter.
It’s the same mentality that dogs have employed for millennia: bury your bones, and they’ll be waiting for you when you return and dig them back up.
Then, back at the Paleon, everyone was asked to share the highlight of their experience at Triceratops Gulch.
Most participants mentioned their favorite fossil, digging in the dark, and hearing the "Jurassic Park” theme as performed by North.
“It was a great opportunity for us to hear Alanna play our violin,” Amy said.
Moments like this are what made the Triceratops Gulch Project such a unique experience for Mossbrucker and the people who keep coming back to dig in Glenrock, year after year.
They’re collecting pieces of a paleontological puzzle, knowing every fossil they pry from the 67-million-year-old rock is contributing to a bigger picture.
“We get folks from all walks of life out here,” Mossbrucker said. “When we put them together, they’re working together to preserve Converse County's natural history at the Paleon Museum and develop a sharper understanding of what lived here during the Late Cretaceous.”
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
