Final answer:
Gizzard stones found with fossils are called gastroliths, which aided in the digestion of dinosaurs and crocodilians.
Step-by-step explanation:
Gizzard stones, found with fossils, are known as gastroliths.
They were swallowed by animals like dinosaurs and crocodilians to aid in the digestion of their prey. These highly polished stones differ from stream-worn gravels because of their smoothness. When found in geological strata, like the Jurassic sediments of Wyoming, they can provide evidence of the migratory patterns of ancient species, such as sauropods, that may have carried them over vast distances.