Tracking Jersey’s Dinosaurs

An early trove for paleontologists, the Garden State remains
rife with opportunities for fossil hunters.

William Gallagher, an associate professor of geology at Rider University, holds a replica skull of Deinonychus, a raptor-type dinosaur. Behind Gallagher, from the collection of the Geological, Environmental and Marine Sciences Department at Rider, are natural casts and molds of prehistoric shellfish from the Appalachian Mountains.
Photo by Marc Steiner/Agency New Jersey.

It was January, but Paul Kovalski did not hesitate to slosh into the chilly waters of Big Brook in Marlboro. Growing up in Marlboro Township in Monmouth County, he had spent countless hours searching for fossils, no matter the season.

This time, he hadn’t been there long when he noticed the 3-inch-long, black object.

“This thing was sitting on gravel and I said, ‘Please don’t tease me,’” says Kovalski, a dentist, although he tends to identify more with his alter-ego, Dr. Dinosaur.

A trip to the Academy of Natural Sciences in Philadelphia confirmed Kovalski’s hopes. Indeed, his find was a remnant of a hadrosaur, a dinosaur that roamed New Jersey about 70 million years ago.

“That made my day,” he says.

Kovalski’s discovery is a reminder of New Jersey’s stature in dinosaur paleontology. Only 152 years ago, on a small farm in Haddonfield, two men unearthed the most complete dinosaur skeleton then known to science. Though it was only about a third complete and was missing a key component—its skull—Hadrosaurus foulkii (pronounced FOLK-eye) gave scientists a much better picture of dinosaurs.

“New Jersey was really the birthplace for American dinosaur paleontology,” says William Gallagher, an associate professor of geology at Rider University in Lawrenceville, former assistant curator of natural history at the New Jersey State Museum in Trenton, and author of When Dinosaurs Roamed New Jersey (Rutgers University Press, 1997). While “Haddy,” as the creature is nicknamed, was the most significant find, fossil-rich layers provided many other early discoveries.

The state remains rife with opportunities for today’s fossil hunters, most of whom are hobbyists. While professional researchers believe all the major finds have been made, they are still studying New Jersey’s most significant discoveries.

When the cast of Hadrosaurus foulkii went on display at the Academy of Natural Sciences in Philadelphia in 1868, the public got its first chance to see a dinosaur skeleton—a 9-foot-tall, 25-foot-long monster with menacing teeth.

The concept of dinosaurs as prehistoric creatures had been officially birthed only about 25 years earlier by Richard Owen, a British comparative anatomist. Owen had only bones and teeth to work with as he wrote a paper describing the “dinosauria,” or “terrible lizards.”

Naturally, when John Hopkins, a Haddonfield farmer, found odd bones while digging on his property in 1838, he was not sure what to make of them. But William Parker Foulke, a lawyer and Academy of Natural Sciences member who learned of the find twenty years later, had a notion.

Foulke called in his friend Joseph Leidy, then a paleontologist for the Academy of Natural Sciences. Together, they excavated the Haddonfield site and unearthed 49 bones and teeth. Leidy described the fossils at a meeting of the Academy of Natural Sciences in 1858, and named the species (in Latin, of course) “Foulke’s bulky lizard.”

“That was the beginning of the science of the hadrosaurus,” says Dr. Ted Daeschler, curator of vertebrate zoology for the Academy. In his first attempts to recreate the full skeleton, sculptor Benjamin Waterhouse Hawkins had to make an educated guess about what kind of head to give his model. Hawkins ultimately “magnified an iguana skull,” Gallagher says, “because hadrosaurus teeth looked like iguana teeth.”

With the help of subsequent fossil finds, scientists learned that hadrosaurs constitute an entire family of dinosaurs. They also know that “Haddy” was a plant-eating duck-billed dinosaur, sporting a flat snout. And while Leidy was somewhat accurate in describing how it walked on two legs, researchers now think the “hind legs were the primary support, but its forelimbs may have touched the ground,” Daeschler says.

Hawkins’ reconfigured skeleton is gone, although the museum did hold on to the inaccurate skull. It also keeps the original remains under climate-controlled conditions for study. Paleontologists are continuing to research the creature’s diet, physiology, and environment. “We haven’t begun to think of all the questions we want to ask yet,” Daeschler says.

Hadrosaurus foulkii was just one find in New Jersey’s vast paleontologic history. The state’s rocks span many eras of geologic time, from the oldest Precambrian granite in the Highlands (topping 545 million years) to the young barrier islands of the shore, deposited over the last 10,000 years.

Most of what is known about New Jersey’s dinosaurs comes from the late Triassic, early Jurassic, and late Cretaceous eras, as opposed to the main Jurassic period, the era most would think of as the heyday of dinosaurs. During the Jurassic, about 200 million years ago, New Jersey is believed to have been just north of the equator, in the middle of the giant supercontinent Pangaea. It was just starting to separate from its neighbor, present day Morocco, when the continents began drifting toward their current positions. New Jersey was also largely mountainous, with more erosion than deposition, Gallagher says, explaining the lack of Jurassic fossils.

In the Triassic, when the earliest dinosaurs rumbled the Newark basin—which runs northeast from Hunterdon County to Bergen County—about 230 million years ago, they left tracks in the riverbeds that lined the basin. Sediments were deposited over the hardened tracks, preserving them.

“It’s the beginning of the age of dinosaurs,” Gallagher says, and their evolution is evident. “From one side of the basin, the older side, to the other side, the younger side, you can see this sequential growth and diversification,” he says. In older deposits, there are tracks of a small, three-toed, bipedal theropod known as Grallator. The younger rocks, on the other hand, yield both Grallator tracks and those of a much larger three-toed dinosaur called Anchisauripus.

The Newark basin has also yielded evidence of Triassic reptiles, such as the skull of a phytosaur—a relative of early crocodiles—and a near-complete skeleton of Icarosaurus seifkeri, a gliding lizard.

But the state’s most prominent finds have come from the Cretaceous, 65 to 150 million years ago, in a belt stretching from Salem County to Monmouth and Middlesex counties. Here, Gallagher says, the deposits were laid down as a result of fluctuations in sea level over the 85-million-year period.

Hadrosaurus foulkii was discovered in this belt. So was the first partial skeleton of a meat-eating dinosaur in North America: Dryptosaurus, a fast and agile hunter, about 18 to 20 feet long, that might have preyed on the smaller hadrosaur. In his Rider office, Gallagher holds up one of its claws, which is about 9 inches long unfurled. Workers in a Barnsboro mine found the fossil next to its phalanx, or finger bone, in 1866.

The greenish sand called marl that preserved Cretaceous fossils was mined during the nineteenth century as a fertilizer, so it was not uncommon for workers to uncover fossils. “It was the heyday of New Jersey dinosaur discovery,” Gallagher says. People also found the remains of sea turtles and crocodiles, as well as extinct creatures like mosasaurs and plesiosaurs.

Scientists also have a good idea about the state’s Cretaceous insect population through pieces of amber. The mineral has yielded beetles, cockroaches, stingless bees, and some of the oldest known ants. “One out of every 100 pieces will hold a bug or a spider or some insect,” Gallagher says.

Cretaceous deposits offer the most opportunity for today’s fossil hunters. There’s easy access to collecting sites such as Poricy Brook Park and Big Brook Preserve in Monmouth County.

Collectors won’t go home empty-handed. Hadrosaur bones may be hard to come by, but remnants of Cretaceous life are fairly common, including shark teeth and ancient sea creatures called belemnites. It’s even possible, though extremely rare, to turn up bones of later creatures like mastodons or sloths, which were sloughed off as glaciers retreated during the last ice age.

While most major paleontology projects today happen out west, in places like the Badlands of South Dakota, Daeschler says even inexperienced Jersey hunters can produce great finds. “You always have to keep your eyes open,” he says. “Sometimes, something really interesting will turn up.”

Glen Ridge-based science writer Kristina Fiore is a reporter for MedPage Today.

Touring NJ’s Top Paleontology Sites

It’s not exactly Jurassic Park, but you can stand on top of the state’s Jurassic-period deposits on the grounds around Lambert Castle Museum in Paterson ( The castle—with its unparalleled view of New York City—sits atop the 200-million-year-old lava flows that helped separate New Jersey from Africa when the supercontinent Pangaea split apart. If that’s not awe-inspiring enough, remind yourself that dinosaurs once walked where you’re standing.

Visit the Newark Museum on Sunday, May 2, for Dinosaur Day. Hands-on workshops and demonstrations will cover aspects of dinosaur life, including the sizes and shapes of the animals that roamed the Garden State. While you’re there, be sure to see the interactive Dynamic Earth exhibit for more on these prehistoric lizards.

Check out the Triassic-period tracks left by the bipedal dinosaur Grallator at the Rutgers Geology Museum in New Brunswick ( Grallator was originally discovered in the red shales of Towaco.

Continue to head south to Monmouth County for fossil collecting. Step back into the Cretaceous period at Big Brook Preserve or Poricy Brook Park. Enter Big Brook from Hillsdale Road in Colts Neck, but be sure to obey any “no trespassing” signs upstream from Boundary Road. Enter Poricy Brook in Middletown through Lincroft Road between Nutswamp and Oak Hill Roads. Be aware that both sites regulate digging and have a limit on the number of fossils you can take.

Head southwest to the New Jersey State Museum in Trenton ( for its display of New Jersey specimens in the Fossil Mysteries exhibit. Unfortunately, the model of Hadrosaurus foulkii is not currently on display, since the Natural History Hall is closed for renovation.

Visit the site of the Hadrosaurus foulkii discovery in Haddonfield. In 1984, Boy Scout Chris Brees pinpointed the location of the find at the end of Maple Avenue. The Academy of Natural Sciences funded his Eagle Scout project to erect a monument commemorating the discovery. Today, the site is a National Historic Landmark. Feel free to poke around the sediments of the adjacent ravine. Maybe you’ll find Haddy’s skull.

While you are in Haddonfield, hop over to Hadrosaurus Lane to ogle a bronze sculpture of the state dinosaur. Haddy earned the designation in 1991 after students at Strawbridge Elementary School in Westmont petitioned for the status.

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