Goniatite is any cephalopod mollusk belonging to the order Goniatitida. Goniatites have coiled shells divided into chambers by zigzag partitions. They first appeared in the upper Devonian period, about 350 million years ago. The group became extinct at the end of the Permian period. They are useful as zone fossils. Goniatites and ammonites belonged to the same subclass Ammonoidea.