Index Fossil

Real World Example

Imagine trying to figure out when an old photograph was taken based on the hairstyle of the people in it. Just as certain hairstyles are unique to specific time periods and can help you date the photo, an index fossil is a fossil from a species that lived during a short, well-defined time frame and can help you date the surrounding geological layers. In this analogy, the hairstyle is like the index fossil, providing a timestamp for the photo, just as the index fossil does for the rock layer, helping to determine the age of other fossils found in the same or nearby layers.