Squalicorax kaupi, Scapanorhyncus texanus lower tooth, Scapanorhyncus texanus upper, Xiphactinus audax, Cretolamna sp., Cretolamna appendiculata, Enchodus ferox, Otodus obliques
Vertebrate Fossils
Vertebrate fossils generally are not common in NJ, with the exception of shark teeth. These are most often found by sifting sediment through a wire mesh screen, usually about 1/4 to 1/8 inch screen. Most of the teeth are Cretaceous or Paleocene in age, however, Eocene and Miocene teeth have been found at a few localities. Sharks are of the class Chondricthyes, in which the skeleton is composed entirely of cartillage. Cartillage is rarely preserved unless it has been calcified. Usually only the vertebra centra, dermal denticals, and fin spines are preserved.
Bony fish of the class Osteichthyes are found alone with shark teeth, though they are usually less common or very small. Sometimes jaws with the teeth still embedded are found. Common Cretaceous bony fish include Enchodus and Anomeoudus.
|
|
From upper left to lower right:
Squalicorax kaupi, Scapanorhyncus texanus lower tooth, Scapanorhyncus texanus upper, Xiphactinus audax, Cretolamna sp., Cretolamna appendiculata, Enchodus ferox, Otodus obliques |
Besides the remains of fish teeth, other vertebrate fossils are sometimes found, mostly reptile. Turtle shell fragments are not uncommon, especially at the K/T bone bed between the Navesink and Hornerstown formations. This bed has produced most of the complete turtle and crocodile skeletons found in NJ. Crocodile and mosasaur bones and teeth, highly prized among collectors, are scarce. Dinosaur fossils from the Cretaceous are extremely rare, since NJ was under water during most of this period. Footprints from the Triassic period have been found in large numbers in northern NJ, however almost no bone material has been found. Only three partial skeletons have been found during over 150 years of collecting. Since the decaying corpses had to be transported for miles from rivers or estuaries, they normally would have been torn appart by scavengers, such as sharks. Thus, only exceptional circumstances would allow a relatively complete dinosaur such as Hadrosaurus foulkii to be buried quickly enough in marine sediments to be preserved.
|
Several crocodile scutes, which served as armor on the back and head of the animal |
|
A partial crocodile jaw |
The rarest fossils found in the Cretaceous of NJ are those of birds and mammals. The bones of both were very small and delicate, hindering preservation. The teeth of mammals are especially difficult, since most are so small they require a powerfull hand lens or microscope to be identified.
| A mosasaur tooth |
Send questions or comments to: