Fossils of aquatic life, in the form of a belemnitida from the Jurassic have been found within the modern borders of Chula Vista. It is not until the Oligocene epoch that land life fossils have been found; although Eocene epoch fossils have been found in nearby Bonita. It isn't until 10,000 years ago, that human activity has been found within the modern borders of Chula Vista, primarily in Otay Valley of the San Dieguito people. The oldest site of human settlement within the modern boundaries of Chula Vista, was named Otai by the Spanish in 1769, and had been occupied as far back as 7,980 years ago. Another place where humans first settled within the modern boundaries of Chula Vista was at the Rolling Hills Site, which dates back to 7,000 years ago.