An index fossil is:
A) a fossil found in a particular site.
B) the ideal specimen of that species that all examples must follow.
C) a fossil used to categorize a stratigraphic layer.
D) the type specimen of a species.

Question

Quizplus · Accepted Answer

An index fossil is a fossil used to categorize a stratigraphic layer, as it is a fossil that is widespread and limited in time, allowing for the correlation of rock layers across locations. A and D are incorrect because they are not complete definitions of what an index fossil is, and B is incorrect because there is no such thing as an "ideal specimen" for a species.

An Index Fossil Is