Inoceramus is a genus of extinct pelecypods or clams that lived during the Jurassic and Cretaceous periods. They were widespread during the time this specimen lived. Inoceramus' distinctive shell is large, thick and concentrically wrinkled.
The pits in the dorsal region are where the ligaments that closed the shell were anchored. This 70 million year old bivalve is from the Upper Cretaceous Chico Formation found in Tehema County, California.