What type of fossils are of organisms that lived over a wide area for a fairly short period of time and are used to determine the age of the rock it is in?
ossicles
inventory fossils
rate fossils
index fossils
Fossils are used to determine the ages of rock layers. Index fossils are the most useful for this. Index fossils are of organisms that lived over a wide area. They lived for a fairly short period of time. An index fossil allows a scientist to determine the age of the rock it is in.