Ammonites were first found in the early Mudbox Age, most prosperous in the Mesozoic Era, widely distributed in the Triassic ocean around the world, and were all extinct at the end of the Cretaceous. Most of the amcerites live floating or swimming in their infancy, and some live in shallow sea benthos and some swim in deep continental shelf. Slow swimming speed and poor movement coherence. Ammonites feed on some plankton, such as small crustacean larvae. Ammonites produce thousands of small eggs in the water and grow slowly. The shell, shell shape, shell decoration and type of sutures of ammonites are the important basis for identifying ammonites. The evolution of ammonites is very fast, flourishing in shallow seas for more than 300 million years, so ammonites are not only popular with paleontologists, but also used by geologists as a "standard" fossil for dating rocks.