The New Egypt Formation is a Late Cretaceous marine formation in New Jersey, part of the Monmouth Group and dating to the late Maastrichtian. Its fossils, especially from Spheno Run, include abundant invertebrates, turtles, mosasaurs, sharks, bony fish, and rarer dinosaur remains from carcasses washed out to sea, some showing scavenging and water immersion. The formation is especially significant for preserving the most complete late Maastrichtian dinosaur fauna known from the eastern United States, including Dryptosaurus and indeterminate hadrosaurs. By combining marine and terrestrial remains, it offers a rare view of life along the ancient Atlantic Coastal Plain near the end of the Cretaceous.