Authentic real fossil ammonite (ammonitic or ammonoid category) Spiny Surriceras from the Cretaceous period .This ammonite species is known for its spiny shell and is quite rare among ammonites.The spines are very prominent on this ammonite and it is sized approximately 4.5   inches across by 1 1/2  inches deep and weighs about 2 pounds.This particular ammonite comes from the Atlas mountains of Northern Africa.AMMONOIDEA IN THE CLASS CEPHALOPODA, PHYLUM MOLLUSCA,,,evolved from nautiloids in the early Devonian period, about 400 million years ago. They were abundant in world seas for the next 370 million years. They suddenly vanished at the end of the Cretaceous period. These extinct marine animals, which thrived in the Paleozoic and Mesozoic Eras,, 400 to 65 million years ago,,, were cephalopods, and are thus related to squid, octopus, cuttlefish, and the chambered nautilus. Ammonites were able to swim, thanks to the unique construction of their shell, which was divided into a series of air chambers. The air in the chambers provided buoyancy for the animal to float; like modern cephalopods and they probably moved through the water using water jet propulsion.Shipping in the US mainland will be FREE by USPS priority and all other shipping locations worldwide, where allowed by law,will be $31.99 USPS priority.