Paleontology and geology

During the Tertiary, extensive erosion of upland areas occurred in northern New Jersey as southeastward-flowing streams carried large quantities of sediment to coastal areas. Sea level fluctuations continued to influence the sedimentation and environmental habitats in the coastal plain of southern New Jersey. Early Tertiary deposits are rich in bryozoans, corals, and echinoids, typical of warm, shallow waters. Fossil shells of brachiopods are found in Ocean and Burlington Counties, while shark teeth are a common find in Shark River Park in Monmouth County. Bone fragments and teeth of both marine and terrestrial mammals have also been found, but are less common. Fossil traces of burrowing shrimp are well preserved in southern New Jersey, while microfossils, such as foraminifera and diatoms, are widespread and often used to determine the age of Tertiary marine deposits. This map indicates that the primary exposures of Tertiary rocks are in central New Jersey and south.