Paleontology and geology

Most of New Jersey's exposed Precambrian rocks are metamorphic and igneous, and therefore devoid of fossils. However, the New Jersey Geological Survey recently discovered stromatolites in the 1.2 billion-year-old Franklin Marble. This marble was formed from limestone deposited in a marine environment. Stromatolites in the marble provide the earliest indications of ancient biological activity in this area. This map indicates the presence of Precambrian rocks in northwestern New Jersey.