Ammonites/ˈæmənaɪts/ are an extinct group of marine invertebrate animals in the subclassAmmonoidea of the classCephalopoda. These molluscs are more closely related to living coleoids (i.e. octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appear during the Devonian, and the last species died out during the Cretaceous–Paleogene extinction event.
Macrofossils (occasionally spelled "macro-fossil") are preserved organic remains large enough to be visible without a microscope. Most fossils discussed in the article Fossil are macrofossils. The term macrofossil stands in opposition to the term microfossil (a.k.a. "micro-fossil"). Microfossils, by contrast, require substantial magnification for evaluation by fossil-hunters or professional paleontologists. As a result, most fossils observed in the field and most "museum-quality" specimens are macrofossils.