Fossils (Ammonite) 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.
Ammonites are an extinct group of marine mollusks related to octopuses, squid, and cuttlefish.
This Ammonite 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.