Fossils are important tools in understanding an area’s local geology. They often come from prehistoric creatures that existed during specific geologic time periods—giving geologists a relative idea of how old the fossil-bearing rocks are.
The ostrea is an ancient oyster related to the oysters you eat!
This ostrea is 100 million years old (mid-Cretaceous) and was found in the lutites of the Chonta Formation in the Agua Caliente Dome. Because it is a marine fossil, its tell us that this area was once under the sea.