Simplify the following text for a Grade 9 native English-speaking person.
Original: The oldest natural history of this area related to mammals manifests in a series of rock outcrops about one third of a mile south of Goat Rock Beach , positioned above the shoreline on a low lying marine terrace .
Simplified: 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 .