Based on the age determined, do you think that this group of fossils could be considered index fosslis? Why?

Question

Fossils Occurrence and the Age of Rocks

Answer 1

Index fossils are fossils of creatures that existed for a short period of time. A good index fossil should also be distinctive (hard to confuse with other creatures from a different period;) wide ranging (its helpful if the fossil appears worldwide) and common (if fossils of the creature are rarely found they are not much use!)

So, once you know that, say, a certain type of trilobite lived between 570 amd 500 million years ago, you know that any rocks with that trilobite fossil in are 570-500mn years old. This also gives a date for any other fossil found in the same strata.