Question

the principle that states that if we can estimate the age of the fossils, we can make assumptions about the age of the sedimentary rock layer in which the fossil is found.

Answer 1

Faunal Succession: Similar to the law of superposition is the law of faunal succession, which states that groups of fossil animals and plants occur throughout the geologic record in a distinct and identifiable order. Following this law, sedimentary rocks can be "dated" by their characteristic fossil content. Particularly useful are index fossils, geographically widespread fossils that evolved rapidly through time.