AMMONITE
(pronounced AM-uh-nite) Ammonite was an early mollusk, The last animal similiar is the nautilus sometimes refered to as "the living fossil" These animals were protected by a chambered shell . Ammonites ranged in size from under an inch to about 9 feet  in diameter. The animal could enter air into it's shell and expell it causing it to raise up and down like a submarine. Hence the first submarine named the "nautilus" both in fition and in real life. They appeared during the Devonian and went extinct with the dinosaurs. The animal could push water through like a jet. Ammonites are common and are used as time markers. Some have fantastic colors and are sold as jewelry, this is called ammolite. Ammonites are available in the marine section of our fossil catalog.