Ammonites (also know as "Ammon's Stones"): They are named for their resemblance to the rammed horns of the Egyptian god Ammon. Ammonites are an extremely advanced subclass of Cephalopods. Their shells range from thick to thin, smooth to very ornate. As the animal Matured and grew, it progressed out of its shell, closing off the chamber after it. A fully matured ammonite reached the outer opening of its shell, having left behind many air-filled chambers for buoyancy. As fossils, ammonites resemble the nautilus shape, and with their rich coloration - browns, grays, blacks - are a beautiful sampling of natures past. The size of this one of kind specimen is about 4 1/2" x 3 3/4" x 1/2 "