The oldest natural history of the area is related to marks made by mammals in an area of rock about one third of a mile south of Goat Rock Beach. In uplifted sea stack formations, there are rubbing marks about two to four meters above the ground surface, too high of a rubbing mark for modern bovids. Mammoths are thought to have traveled here as recently as 40,000 years ago, and are thought to have made these rubbing marks. Mammoth fossils have been found at Bodega Head, which is a few miles south of Goat Rock Beach.