During what period(s) did tyrannosaurus exist on Earth? ____  period(s)     Amphibians existed on Earth from _____  to  ____  period.     How old would a rock that contains shark and archimedes be? _____ to _____MA     How old would a rock that contains ceratities, fenestella, and amphibian be? _____ to _____MA     How old would a rock that contains olenellus be?  _____ to _____MA

Some fossil animals (fauna) and plants (flora) have existed on earth for large spans of time, while others known as index fossils were found all over the planet but only existed for a brief period of time. Both can be an important tool for dating rocks. If we identify the fossils in a rock and determine what periods in Earth’s history these were all present at the same time, we can use their overlap to approximate the age of the rocks.

Instructions: You will be determining the approximate age of rocks by using fossil record below. The figure on the right gives the age ranges of some fossils; use these to answer the following questions:

    During what period(s) did tyrannosaurus exist on Earth? ____  period(s)
    Amphibians existed on Earth from _____  to  ____  period.
    How old would a rock that contains shark and archimedes be? _____ to _____MA

    How old would a rock that contains ceratities, fenestella, and amphibian be? _____ to _____MA

    How old would a rock that contains olenellus be?  _____ to _____MA