When Dinosaurs Roamed the Streets of New York City: Part One of a Three-Part Series on the Palisades

By Marcia Anderson

Rutiodon Manhattanensis

Rutiodon Manhattanensis

A little over 100 years ago, “Dinosaur Fever” hit New York City. On December 21, 1910, the front page of the New York Times announced the discovery of a crocodile-like dinosaur that once basked in the sun on the beaches of NYC and the Palisades. This was followed by a Christmas Day full-page article entitled, “When the Giant Dinosaur walked down Broadway.”

The well preserved skeleton of a 30-40 foot long dinosaur, standing 15-18 feet tall was discovered in the Palisades by a group of Columbia University students. The bones were found just south of the Palisades Interstate Park’s boundary in Edgewater, N.J., about a half mile from where the new George Washington Bridge was to be built. The bones were in a layer of soft shale at the edge of the Hudson River, embedded in a 5,000 pound block of stone that was eventually cut from surrounding rock and transported to its new home in the American Museum of Natural History (AMNH).

He was of the genus Phytosaurus, an aquatic crocodile-like reptile with a long-toothed snout, a long flat tail and eyes and nostrils that were set on top of his head. The reptile was from the late Triassic Age, about 210 million years ago and was aptly named “Clepsysaurus manhattanesis.” Other Triassic brethren found along the Palisades were Coelacanth fish and Icarosaurus, one of the earliest winged reptiles. The NYC/NJ region was a veritable “Triassic Park” at that time.

The curator from the AMNH described the creature as “a cross between a crocodile and ostrich,” on mega steroids. A relative of an Iguanodon, he was originally thought to be an herbivorous dinosaur (a plant-eater), but is now believed to be carnivorous. The beasts roamed at will all along the banks of the Hudson, when most of North America lay near the Equator and enjoyed a sub-tropical climate.

Geology of the Palisades: The sandstone and shale layers of rock in which he and other creatures of the same period were found, were deposited in the early Triassic Period by the weathering of mountains and erosion of material deposited by rivers in the area. Toward the end of the Triassic, about 200 million years ago, the supercontinent, Pangaea, began to break apart.  That was when eastern North America began to separate from northwestern Africa, creating the Atlantic Ocean. The earth’s crust diverged in many places forming rift zones enabling large quantities of molten rock, or magma, to be released from deep within the Earth. Much of this magma did not breach the surface of the Earth. Instead, it flowed horizontally between the layers of sandstone and shale – like meat in the middle of a sandwich. The intense heat and pressure of the magma intrusion metamorphosed the surrounding sedimentary layers and thus preserved creatures trapped in them for us to find millions of years later. This particular intrusive river of hot magma cooled and is now known as the Palisades Sill.

Feel free to re-discover this early New Yorker for yourself and give the kids a thrill at the same time. He now resides in the AMNH Hall of Vertebrate Origins, as AMNH 4991,or Rutiodon manhattanensis. http://en.wikipedia.org/wiki/File:Rutiodon_manhattanensis_AMNH_4991.jpg  His bones are still embedded in the black stone in which he was found, flanked by skeletons and skulls from similar animals. The American Museum of Natural History (http://www.amnh.org/) is located at 79th Street and Central Park West, New York City.

