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Why Are There Fossils Here? About the Big Brook Fossil Area - New Jersey

Hadrosaurus foulkii is the first dinosaur specimen from North America. The 35 bones from this specimen are housed at the Philadelphia Academy of Natural Sciences

Due to the everlasting popularity of dinosaurs the Triassic, Jurassic, and Cretaceous time periods are well known to the public. When people think of the Era of the Dinosaurs, they may think of Paleontologists digging out west in the badlands of North America where the famous 19th century "Bone Wars" occurred.

However, not many people know that America's East Coast has its share of Dinosaurs! States all along the East Coast, from Main to Alabama all contain fossil deposits from the age of dinosaurs. In fact, in 1838 North America's very first nearly complete dinosaur was discovered in Haddonfield, New Jersey. The specimen, a duck billed dinosaur (Hadrosaurus foulkii), was later studied in 1858. The first Mosasaur fossil described from North America was also discovered here!

Today amateur fossil hunters can still go to New Jersey and find Dinosaur aged fossils. Anyone with an interest in fossils can enjoy a trip to New Jersey and search for Cretaceous fossils. One of the better known areas is in Monmouth County where Cretaceous age fossils can be found. Throughout the county, Big Brook and surrounding brooks cut through the ground, digging though the layers of earth. These brooks erode through recent layers, cut into the Pleistocene, and finally carve away at ancient fossil bearing Cretaceous deposits.

River Worn Hadrosaur Dinosaur Teeth - Although all dinosaur material is scarce, hadrosaur teeth tend to be the most common type of Dinosaur fossil found.

This is a Dryptosaurus dinosaur manual phalanx "finger" bone found in one of the brooks in New Jersey by Andrew Darling. This is a rare find. It has been donated to the Rowan University. If dinosaur bone is found, I recommend donating it to the NJ State Museum or to Rowan University so it can be catalogued and studied, as dinosaur material is scarce in the brooks.

Why are there Cretaceous fossils here?

During the Cretaceous, our continents were nearly in their present positions. However, the Earth was much warmer. This resulted in high sea levels. As a result, Europe was composed of numerous islands, while most of the North American coastal plain was submerged. States such as Georgia and Florida were completely submerged. The high sea levels also caused North America to be split in two. A great interior seaway flowed through much of the great plain states, from Texas to North Dakota and through Northern Canada. This can be seen in the sketch below.

New Jersey was also submerged. Remains of prehistoric animals accumulated on the sea floor that is now New Jersey. These remains were buried by the nutrient rich sediments coming from shore, and are now part of fossil bearing layers of the Monmouth Group. These Cretaceous marine fossil layers are exposed by brooks that cut down through sediments in the Big Brook area. Numerous fossils of sharks can be found as well as invertebrates such as mollusks and Belemnites. Also, the great reptiles that ruled the seas in the Cretaceous can occasionally be found. These creatures include Mosasaurs, Pleisiosaurs, and large Crocodiles. To learn about Mosasaurs, go to the Mosasaur Gallery.

However, since this area of New Jersey was only miles from the coast, the remains of land animals occasionally washed out to sea. Although rare, fossils of land animals can be found. These fossil remains are often pieces of dinosaurs, such as Hadrosaur teeth and bone fragments.

Fossils in the Big Brook area have been washed out of their sediments by the water action. These fossils can simply be found in Big Brook and surrounding brooks by screening gravel bars and walking the creek beds.

Rough sketch of North America during the Cretaceous

Book about the Geology and Paleontology of New Jersey:

The following book: When Dinosaurs Roamed New Jersey (Link to Amazon) is a great book to learn about New Jersey Paleontology and the geologic history of New Jersey. It is very accurate, as the author is a scholar in the field of paleontology. There is even a section that describes fossil hunting sites in New Jersey.