Sunday, May 26

The Crestone Eagle is a nonprofit monthly newspaper serving Crestone and the San Luis Valley

Unearthing the dinosaurs

The rich geological history of Southern Colorado 

By Daniel Hart

A lush, dense, and humid tropical lowland rainforest is alive with a myriad of creatures foraging for food, rearing their young, hunting, and doing all the things creatures do to pass the time.

It’s 170 million years ago, the Jurassic Period, and those creatures are dinosaurs. There are no Sangre de Cristo Mountains or a San Luis Valley yet, only the tropical lowlands.

After a hundred million years of continental drift in this same location, it is now the 

Cretaceous Period, and waves from the Western Interior Seaway roll into a marshy shoreline. This nexus has every variety of terrestrial and aquatic dinosaur plying the waters and lowlands.

A few dozen miles inland from the seaway, the modern Rocky Mountains (the Sangre de Cristos included) are in the process of upheaval. This uplift formed the San Juan and Sangre de Cristo Mountains as one range and then tore them apart, leaving the San Juans to the west and the Sangre de Cristos to the east. The San Luis Valley was left in between. This made the second largest rift valley in the world, next to Africa’s Great Rift Valley.

The rich biological and geological history of Southern Colorado came into dramatic focus in 1877, when the fossil bounty of 170 million years was unearthed in Cañon City’s Garden Park area. This discovery initiated the “Great Dinosaur Rush”, as fossil seekers from the country’s most esteemed institutions swarmed the area. Edward Drink Cope of the Academy of Natural Sciences in Philadelphia and Othniel Charles Marsh of the Peabody Museum of Natural History at Yale were primary leaders in the Rush.

Cope and Marsh were bitter rivals. As they developed fossil quarries, they employed spies in each other’s camps, destroyed and stole each other’s specimens, sabotaged each other’s funding, blasted quarries to stymie discovery, and attacked each other in popular and academic publications, leaving both disgraced and bankrupt.

Despite the drama, they discovered more than 130 dinosaur species, 20 of which were entirely new to the world, including diplodocus, stegosaurus, allosaurus, and camarasaurus.

Southern Colorado is so prolific in dinosaur fossils that much of the Jurassic collection in the Smithsonian is from Garden Park. Other museums with Garden Park fossils are the Cleveland Museum of Natural History, American Museum of Natural History, Denver Museum of Nature and Science, and the Carnegie Museum of Natural Science. Zach Reynolds of the Royal Gorge Dinosaur Experience in Cañon City reinforces this idea, and comments that, “The impact of paleontology in this little area is pretty huge on the world scale, although not many people know it, and you wouldn’t think it just by looks.”

Despite the “Bone Wars” ending, significant new fossil discoveries continue in the area. In 1992, the most intact skeleton of a stegosaurus was found. In 1999, an ankylosaurus trackway was discovered on Skyline Drive. The most recent discovery was made in October 2022, by Chad McCarty, whose quest for geodes resulted in striking fossil paydirt. He stumbled on the rare, intact tibia and fibula of an unknown species of sauropod.

In a well-planned day trip from Crestone (it’s about a two-hour drive to Cañon City) you can see all the exhibits and resources highlighted. On the way into town, you can stop at the Royal Gorge Dinosaur Experience which has an outdoor dinosaur walk with life-sized replicas, a working paleontology lab, and an excellent museum with guided tours that detail the region’s geological history, history of the “Bone Wars”, and showcase many reconstructed dinosaurs and fossils.

Next, head over to Skyline Drive to the Ankylosaurus Trackway, which is marked with interpretive signage. After you make it over Skyline Drive, the recent tibia and fibula along with other fossils from the region can be seen in the Royal Gorge Regional Museum and History Center in Cañon City. The Garden Park Cleveland and Marsh quarries are marked and can be explored through self-guided, interpretive walks. In just a day, you’ll have taken yourself 170 million years into the past and back. Not bad for a day trip, and no time machine required.

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