Wikipedia
Agoniatites
Agoniatites is a genus of primitive ammonoids belonging to the order Agoniatitida family Agoniatitidae.
Species of this genus were fast-moving nektonic carnivore shelled ammonoids. They lived in the Eifelian and Givetian ages of the middle Devonian period, which occurred 385.3-397.5 million years ago.
Vanuxemi agoniatites is a rare species in this group which is the only ammonoid found in the Hamilton Group (Mahantango Formation) in Pennsylvania and New York.