Mollusks

Modern mollusks are an incredibly diverse group of animals that includes snails, cephalopods (octopuses, squids, cuttlefish, and the chambered nautilus), bivalves (clams, oysters, mussels, and scallops), as well as a few additional smaller groups. Mollusks were not as diverse during the Devonian Period as they are today, but they still left behind a rich fossil record in New York. Fossils of clams and cephalopods are especially common.

Cephalopods

Examples of Devonian cephalopods from New York

Agoniatites sp.

Ponticeras perlatum

Spyroceras sp.

Dolorthoceras sp.

Fossil ammonoid Manticoceras sinuosum from the Devonian Cashaqua Formation of Yates County, New York (PRI 49803). Longest dimension of specimen is approximately 6 cm. Model by Neil Pezzoni.

Fossil specimen of the Devonian cephalopod Tetranodoceras transversum from the Marcellus Shale (Cherry Valley Limestone Member) of Cayuga County, New York (PRI 5365). Longest dimension of specimen is approximately 15 cm. Model by Emily Hauf.

Holotype of the cephalopod Agoniatites intermedius (PRI 5370); from the Devonian Cherry Valley Limestone of Cayuga County, New York. Longest dimension of specimen is approximately 29 cm. Model by Emily Hauf.

Fossil specimen of the cephalopod Tornoceras uniangulare from the Devonian Geneseo Shale of Tompkins County, New York (PRI 55004). Maximum diameter of specimen is approximately 6 cm. Model by Emily Hauf.

Fossil specimen of the cephalopod Spyroceras sp. from the Devonian of Onondaga County, New York (PRI 70598). Length of specimen is approximately 4.5 cm. Model by Emily Hauf.

Fossil specimen of the nautiloid cephalopod Casteroceras alternatum from the Devonian Marcellus Shale (Cherry Valley Limestone Member) of Madison County, New York (PRI 5363). Length of specimen is approximately 25 cm. Model by Emily Hauf.

Bring a straight-shelled nautiloid home!

Many nautiloids had long, straight shells called orthocones. Later forms were bent or coiled. Some nautiloids grew to gigantic sizes (over 20 feet long!), and they were the first large predators in the ocean.

Order

Learn more about fossil cephalopods

Gastropods (Snails)

Examples of Devonian gastropods from New York

Loxonema

Platyceras ventricosum

Bembexia sulcomarginata

Euomphalus rudis

Pleuronotus decewi

Retispira leda

Fossil gastropod Palaeozygopleura hamiltoniae from the Devonian Skaneateles Formation of New York state (PRI 49889). Longest dimension of specimen is approximately 5 cm (whole slab) / 3 cm (shell). Model by Neil Pezzoni.

Fossil specimen of the gastropod Naticonema lineata from the Devonian Hamilton Group near Geneseo, New York (PRI 76749). Maximum dimension of specimen is approximately 3.5 cm. Model by Emily Hauf.

Fossil gastropod Platyostoma lineata from the Devonian Hamilton Group of West Bloomfield, New York (PRI 50368). Longest dimension of specimen is approximately 3.1 cm. Model by Neil Pezzoni.

Learn more about gastropods

Bivalves

Examples of Devonian bivalves from New York

Grammysia bisulcata

Goniophora hamiltonensis

Fossil specimen of the bivalve Grammysioidea arcuata from the Devonian Hamilton Group of Herkimer County, New York (PRI 76729). Longest dimension of larger valve is approximately 5.5 cm. Model by Emily Hauf.

Fossil specimen of the bivalve Grammysia bisulcata from the Devonian Skaneateles Formation of Onondaga County, New York (PRI 76730). Length of specimen is approximately 6.5 cm. Model by Emily Hauf.

Fossil specimen of the bivalve Grammysia elliptica from the Devonian Ithaca Formation of Tompkins County, New York (PRI 76731). Longest dimension of specimen is approximately 5.5 cm. Model by Emily Hauf.