Ophiomorpha nodosa from the Navesink formation

A common find in the brooks of Monmouth county, NJ are these preserved burrows called Ophiomorpha nodosa. They are the former homes of a species of Ghost shrimp often attributed to the genus Protocallionassa. These are technically trace fossils and not true fossils but they are interesting none the less.

The Navesink was lain down in the latest Cretaceous (Masstrichtian stage) as a layer of sediment that was (at that time) moderately deep water.