Definition
An index fossil is like a time capsule from the past! 🕰️ It's the preserved remains of an organism that lived for a relatively short period and was geographically widespread. This makes it super useful for dating rock layers. Think of it as nature's way of stamping a date on a rock. Unlike other fossils, index fossils are not about rare finds but common, easily identifiable species. They help geologists correlate rock strata across different locations. It's like having a universal timestamp for rocks!