index fossil

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

So distinctive is this fossil that paleontologists often use it as an index fossil to determine the age of rock layers.

From Science Daily • Nov. 12, 2025

A good index fossil should be specific to a time period but widespread enough to be found in many places.

From Textbooks • Jan. 1, 2018

The grounds were often more interesting than the matches, the All England Lawn Tennis and Croquet Club being such an index fossil from the nineteenth century.

From The New Yorker • Mar. 2, 2015

There is no specific limit on how short the time span has to be to qualify as an index fossil.

From Textbooks • Jan. 1, 2015