Answer:
Ammonites were common during the Mesozoic Era (245 to 65 mya), They were not found after the Cretaceous period, as they went extinct during the K-T extinction (65 mya).
Explanation:
Answer: below
Explanation:
Examples of index fossils include: Ammonites were common during the Mesozoic Era (245 to 65 mya), They were not found after the Cretaceous period, as they went extinct during the K-T extinction (65 mya).
index fossil: The trilobite is in all three outcrops (it is widespread) and in only one layer per outcrop (it is short lived.)
