Fossilized ammonites are an extinct group of marine invertebrate animals in the class Cephalopoda of the subclass Ammonoidea of the order Anarcestida. Genus and species are unknown. These mollusks are more closely related to the squid and octopus. Overall measurement is 1.5 inches by 1.5 inches. Age: 360 million to 420 million years old (Devonian Period). Location: Richmond County, Virginia. Ryker box included. Note suture marks (showing growth over a period of time) on weathered area of fossil.