The Nestucca Formation in Oregon preserves fossils from the Eocene, especially the Bartonian to Priabonian interval, making it an important fossil-bearing rock unit in the state. Its remains record marine life from that time and include mammals of uncertain classification, sharks and rays such as Heptranchias howelli, Galeocerdo, Isurus, and Raja, and invertebrates including the gastropod Calliovarica oregonensis, the bivalve Nucinella oregona, and the decapod Macroacaena alseanus. The formation is significant for the view it offers into Oregon’s Eocene environments and paleontology.