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Seasons Magazines

Connecticut: The Dinosaur Footprint Capital of North America

Connecticut, for those of us who live here, is currently a state of superlatives. We believe that our state has the most black bears imaginable, the best oaks (just perfect for hiding classified documents), the most prolific shad derby, the craziest weather, the best college basketball teams with the most endearing husky mascot, the most elusive mountain lions, the tastiest scallops, and the biggest sycamores. But most recently, I’ve discovered we can congratulate ourselves for another accolade. It turns out that in addition to all of these notable things, our state is the dinosaur footprint capital of North America. Although Connecticut is currently crisscrossed with freeways, rivers, forests spanning wide valleys and numerous small towns, millions of years ago, it was once teeming with Jurassic creatures and strange, vast landscapes beyond the wildest imagination.

Proof of this claim can be found at Dinosaur State Park in Rocky Hill, where visitors see examples of supersized, three-toed dinosaur tracks and evidence of iconic fossils. Connecticut is literally blanketed with fossilized tracks of dinosaurs from the early Jurassic period. When Edward McCarthy flipped a slab of sandstone with his bulldozer in 1966 at a building site, he witnessed something remarkable: large footprints unlike any he’d ever seen, made by a huge creature with three toes. Construction immediately ceased, and within just a few weeks, it was decided that the site would be preserved as a state park. After careful excavation, the park now has one of the largest on-site displays of dinosaur tracks in the entire world.

Interestingly, fossil tracks are classified separately from the name of the animals that made them. The kind of tracks stippling the landscape in Rocky Hill are called Eubrontes giganteus, made approximately 200 million years ago and named by one of America’s first geologists, Edward Hitchcock, who studied the Connecticut River Valley fossils during the 19th century.

Scientists have yet to discover any remains of the creature that left these footprints in our great state, but it is thought that they belonged to a dinosaur known as Dilophosaurus. The tracks are  between 10 and 16 inches in length and spaced 3.5 to 4.5 feet apart. Eubrontes is now the official state fossil of Connecticut. In the same place, smaller tracks also can be seen. Scientists suggest these were made by younger creatures of the same variety or by a smaller relative such as Anchisauripus.

The dinosaur footprints in the Connecticut River Valley were created due to perfect conditions. In the Triassic and early Jurassic periods, large mudflats were formed and accumulated sediments over a period of 30 million years.

For footprints to take hold like those we have in Connecticut, the mud must not be too wet or too dry. The foot making the ancient impression must have a thin layer of powdery silt and algae so that the indentation is cleanly separated once the weight is taken off of the imprint. Sediments then need to accumulate and fill in the impression.

Over time, these sediments, due to pressure, fill in the depression and solidify, making a positive and negative fossil. After the rock splits cleanly, the negative relief and the positive natural cast are preserved. Connecticut just happens to have the ideal geological profile that allowed for this archeological record to form in abundance.

Connecticut is also the purveyor of very detailed fish fossils and bones from megafauna. One of the most exciting finds took place in 1913 at an estate in Farmington, now the site of the Hill-Stead Museum. The museum houses impressionist paintings by famous artists like Degas and Monet—paintings collected by the original owner, architect and philanthropist Theodate Pope.

Little did Theodate know that something exceedingly rare was hidden in her peat bog. Bones were unearthed from a 12,000-year-old Mastodon, now referred to as the “Pope Mastodon.” This exciting creature that captivates our imagination once stood approximately 9 feet high and was 13 feet in length. Remarkably, it was nearly a complete skeleton, including an impressive tusk and jaw with molars. How remarkable that archeologists can take us in a virtual “way-back machine” by painting a picture of how things once were using the evidence they find.


In the world of paleo-archeology in Connecticut, all paths seem to lead towards The Yale Peabody Museum of Natural History, which has one of the finest collections in the country, if not the entire world. Curators at the New Haven institution have multiple collections, from “deep time” to early human occupation in Connecticut and beyond. Scientists connected to the Peabody have expertise in vertebrate, invertebrate, and anthropological studies. At the moment, the museum is closed for extensive restoration, but Christopher Renton, Associate Director of Marketing and Communications, says they have plans to reopen in 2024 with expanded exhibits. Until now, just a fraction of their collections could be displayed, but with the larger halls, far more fascinating items can be shared with the public in the near future.

The Peabody was founded in 1866 by O.C. Marsh and his uncle, George Peabody. Marsh’s many discoveries from across North America and those of his subsequent colleagues all reside in the Peabody, including the first full skeletons of Brontosaurus, Stegosaurus, and Triceratops, to name just a few. Marsh’s drive launched a notorious competition between himself and paleontologist Edward Cope, coined as the “Bone Wars”– a decades long race to unearth dinosaur holotypes, (an original specimen upon which a new species is identified). This competition seems somewhat akin to man’s primordial task of naming every living creature.

The association between birds and lizards was revolutionized in the 1960s through Peabody Museum’s famous researcher, John Ostrum, who redefined American paleontology.  In 1964, Ostrom was sleuthing around in Montana. As he stared out upon a vast area just ripe for an archeological dig, something unusual caught his eye. It was a large claw sticking up right out of the soil. This turned out to be the remains of a three-clawed dinosaur from the early Cretaceous period; two claws were ordinary but the innermost toe was sharp and sickle-shaped, perfect for slashing at prey.

Ostrum’s discovery was later named Deinonychus, “terrible claw’ in Greek. By examining bones and claw fragments, Ostrum noted a remarkable similarity between dinosaurs and birds. He declared that there was “impressive, if not compelling” evidence “that many different kinds of ancient reptiles were characterized by mammalian or avian levels of metabolism.” Ostrum’s theory, that some dinosaurs had feathers, was finally confirmed with subsequent discoveries that he gratefully lived to see accepted.

The author of Jurassic Park, Michael Crichton, did much of his research at the Peabody. From the Peabody, Crichton, and later Spielberg gleaned inspiration in part from consulting with Ostrum, who described his research to them. The blockbuster film put the name of the novel’s antagonistic dinosaur, velociraptor (based on Deinonychus) squarely into the common vocabulary of every elementary school child in North America.

Non-feathered dinosaurs appeared to be cold-blooded, yet with such high metabolic rates that no one can easily agree whether they were cold-blooded or warm-blooded, after all. It is also a well-known fact that even Charles Darwin sent his top assistant, T.H. Huxley (“Darwin’s Bulldog”), as his emissary to study at the Peabody in the 1870s. Darwin also had argued that there was a link between reptile-like birds and bird-like reptiles, and later doffed his cap to O.C. Marsh by sending the museum a letter to say that the work done there was the most important and greatest proof of his theories of evolution.

Since 1870, the Peabody has had an unbroken tradition of taking college students on archeological expeditions each summer in search of specimens. This is why they have such rare finds, or as Dr. Ajun Bhuller put it: ‘a multitude of Mona Lisas in the world of fossils.’

In speaking with Bhuller, curator of large vertebrate fossils at the Peabody Museum, he said that research points to the fact that present day birds are really living theropods (3-toed dinosaurs). This claim is based upon extensive research that includes microbiology as well as meticulous analysis in the Peabody labs of bone structures both present and past.

The lizard-like Allosaurus, a dinosaur that is one of Dr. Bhuller’s focal points of interest, in fact, had a coat of feathers and short, compact arms that folded close to the body similar to the wing structure of a bird. Using CT Scan technology, Bhuller’s team of college students and world class researchers have been able to tour the inside of the Allosaurus’ skull. They digitally reconstruct what they learn during these virtual forays. In the case of Allosaurus, it’s beak-like mouth as well as its nostrils and air circulation all very much resembles that of a bird.

Bhuller calls birds beautiful organisms that are “finely wrought biological machines.” By studying the evolution of their structures from fossils and looking at modern day embryonic development of related animals, he notes that the most significant moments of evolutionary change take place during the embryonic state. He mentioned that birds as embryos look very much like dinosaurs, so when an imaginary virtual video is played of their evolutionary anatomy, certain significant changes that alter the embryo from dinosaur to bird turn on “like a switch” as different stages of development in apparent self-assembly.

Paleontologists at Yale study fossils like fastidious detectives so that they can replay the assembly process. At the same time, in their molecular labs, they try to figure out how the gene enacts little changes in the embryo leading to the big evolutionary results in biodiversity.

Bhuller is part of an extensive research team at Peabody that includes Derrick Briggs, who he described as the greatest living invertebrate paleontologist, and Jacques Gauthier, who is a principal investigator on the effort to reconstruct the phylogeny of reptiles using gross anatomy and molecular structure. Needless to say, in this spirited community at the Peabody, the word is out that birds are the only surviving dinosaurs, and that the crocodile is the closest living relative of birds, based upon their DNA, gross anatomy, and certain behaviors.

Clearly, Connecticut has proven to be a high-stakes player in the world of paleo-archeology. Undoubtedly, there will be far more for our well-trained team of archeologists to discover here in the years to come.

For those interested in learning more about Connecticut’s premier paleo-archaeology venues: