The basal New Egypt is a massive clayey, glauconiticmarl that closely resembles the Navesink Formation into which it grades below. Ammonites and other invertebrates found at the Spheno Run site correlate well with the middle Severn Formation of Maryland. Spheno Run has so far produced a remarkable number of vertebrate specimens, especially from marine reptiles, including: carapace elements from at least two species of turtles, Peritresius ornatus and Taphrosphys sulcatus; various bone elements from at least two species of mosasaurs including a sizable fragment of dentary bone from Prognathodon rapax and numerous shed teeth from Mosasaurus maximus.
Vertebrate remains also include material from sharks, particularly teeth and unusually large vertebral centra from an individual lamniform shark Squalicorax pristodontus, bony fish, and, rarely, dinosaurs. In addition to the vertebrate collection, Spheno Run also yields an abundance of invertebrate species including: twenty-two bivalves, seven gastropods, six cephalopods, and one each of echinoidea, porifera, and scaphopoda. It is rare to find such an extensive array of both vertebrate and invertebrate species within one horizon in New Jersey.[1][2]
The New Egypt Formation preserves the most complete late Maastrichtian-aged dinosaur fauna from the eastern United States, providing an important record of the dinosaurs that inhabited Appalachia around this time. These remains belong to dinosaurs whose carcasses were washed out to sea, and preserve evidence of being submerged in water and scavenged by sharks & marine invertebrates. The most notable taxon from this formation is the tyrannosauroidDryptosaurus, one of the few predatory theropods known from eastern North America. In addition, remains of indeterminate hadrosaurs, including potential lambeosaurines, are also known. The potential presence of lambeosaurines is notable, as this group is not otherwise known from eastern North America, and is not thought to have still inhabited North America so late into the Maastrichtian.[3][4]
A hadrosaur bone potentially referable to a lambeosaurine. Notable for representing one of the only potential records of this group from eastern North America, and one of the latest records of this group from North America overall.[4][6]
Carter, M. T. W.; Johnson, R. O.; Chamberlain, J. A.; Mehling, C. (2008), "A new vertebrate fauna from the Late Cretaceous (Maastrichtian) New Egypt Formation of New Jersey", Abstracts with Programs - Geological Society of America, 40: 78–79
B. Stahl and D. Parris. 2004. The complete dentition of Edaphodon mirificus (Chondrichthyes: Holocephali) from a single individual. Journal of Paleontology 78(2):388-392
W. B. Gallagher. 1993. The Cretaceous/Tertiary mass extinction event in the North Atlantic coastal plain. The Mosasaur 5:75-154
W. B. Gallagher. 1984. Paleoecology of the Delaware Valley region. Part II: Cretaceous to Quartenary. The Mosasaur 2:9-43
E. S. Gaffney. 1975. A revision of the side-necked turtle Taphrosphys sulcatus (Leidy) from the Cretaceous of New Jersey. American Museum Novitates (2571)1-24
E. L. Troxell. 1925. Hyposaurus, a marine crocodilian. American Journal of Science 9:489-514
G. R. Wieland. 1905. Structure of the Upper Cretaceous turtles of New Jersey: Agomphus. The American Journal of Science, series 4 20:430-444
G. R. Wieland. 1904. Structure of the Upper Cretaceous turtles of New Jersey: Lytoloma. The American Journal of Science, series 4 18:183-196
E. D. Cope. 1875. The Vertebrata of the Cretaceous formations of the west. Report of the United States Geological and Geographical Survey of the Territories 2:1-303
E. D. Cope. 1870. Synopsis of the Extinct Batrachia, Reptilia and Aves of North America. Part II. Transactions of the American Philosophical Society, New Series 14:105-235
E. D. Cope. 1866. [On the remains of a gigantic extinct dinosaur, from the Cretaceous Green Sand of New Jersey]. Proceedings of the Academy of Natural Sciences of Philadelphia 18:275-279
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