Researchers have found a remarkable effect while studying how marine particles sink, which could affect the way scientists assess global carbon fluxes.
Ammonites are an group of marine animals of the subclass Ammonoidea in the class Cephalopoda. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geologic time periods.mmonites are an group of marine animals of the subclass Ammonoidea in the class Cephalopoda. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geologic time periods.
Ammonites fit these demands well, and are the best-known fossils that have been widely used for this. Other important groups that provide index fossils are the corals, graptolites, brachiopods, trilobites, and echinoids (sea urchins).