HOW CAN AMMONITES HELP TO DETERMINE THE AGE OF CERTAIN ROCKS?
* As different species of ammonites lived during different time periods, scientists can use these animals to determine the relative age of the rocks in which their fossils are found (such fossils are called index fossils). (http://www.onlyone.net/ammolite/ammonite%20history.html) * Because ammonites lived exclusively in marine environments, their presence also indicates the location of prehistoric seas.