The Monmouth Group or Matawan Group is a major Late Cretaceous-aged geologic group in the eastern United States, known from New Jersey, Pennsylvania, New York, Delaware, and Maryland.

[1] It comprises a number of geological formations dating from the Santonian to nearly the end of the Maastrichtian, deposited in nearshore environments off the coast of eastern Appalachia, including deltaic and marine ecosystems.

[2] It is highly fossiliferous and preserves a diverse array of fossils, including some of the most prominent dinosaur-bearing deposits of eastern North America.

The following formations are included, from youngest to oldest:[2][3][1] This article about a specific stratigraphic formation in New Jersey is a stub.

You can help Wikipedia by expanding it.