There was a time, millions of years ago, when Orange County was almost completely under water. There was a also a time when the county’s topography was similar to that of a rainforest.
As a result of such occurrences, Orange County is home to many fossilized remains.
Among the county’s fossils is a galloping crocodile-like animal that would munch on petite horse-like animals. It is speculated that this animal would stand on its hind legs and run like a T-Rex, explained Meredith Rivin, associate curator of paleontology at the John D. Cooper Archaeological and Paleontological Center.
Rivin recently talked to a group of about 100 Cal State Fullerton Osher Lifelong Learning Institute members about the county’s fossils in her 90-minute presentation: “The History of Life in Orange County: A Trip Through Time.”
Many of the fossils in Orange County are found in construction sites, Rivin said. Fossilized material is collected quicker when it is found in construction zones because construction crews can help dig out the materials, she said.
Because most of the county was under water until about 20,000 years ago, there is an abundance of marine animal fossils.
Sea levels have been rising since then, Rivin said.
“Orange County hasn’t been sitting here at this latitude over the past 180 million years,” she said. “Because we were covered in ocean during this time, we don’t get a lot of dinosaurs.”
Between the Paleocene and Eocene periods – 60 million to 40 million years ago – Orange County was much like a rainforest, Rivin said.
“It was that warm and wet here,” she said. “We don’t have rainforests here today because the climate is not as warm as it was during the Paleocene and Eocene, and we are further north.”
Since the San Andreas fault began forming about 20 million years ago, Orange County has moved about 150 to 300 miles north of where it used to be, Rivin said.
In the late 1990s and early 2000s, construction crews of the Talega housing tract in San Clemente came across a massive bone bed, an accumulation of fossilized bones.
The bone bed was cut into 49 pieces; 45 went to the Cooper Center and four went to UC Santa Barbara. The Cooper Center, a partnership between CSUF and OC Parks, has since examined three of the sections, finding mostly broken fragments of bones and teeth.
“Mammal teeth are very distinct, and you can tell what kind of mammal it is by just one tooth,” Rivin said.
Some fossilized remains found in the Talega bone bed include: rhino-like brontotheres; running terrestrial crocodiles; large snakes; freshwater turtles; three-toed horses; small camels; tarsier-like primates; and large, hooved predators called mesonychians.
“Our goal is to preserve this material and to do outreach within the community and research,” Rivin said. “Students and volunteers really help us a lot with the collections.”
Volunteers at the Cooper Center learn how to prepare, research and photograph fossils.
The center focuses on four aspects: curating, cataloging, exhibits and research.
At the Cooper Center, Rivin works with professionals and volunteers to uncover Orange County’s history, by way of the fossilized remains that have been found over the years.
“I’m really interested in the history of life on Earth besides people,” Rivin said. One of the center’s most prized possessions is a nearly complete walrus fossil, Rivin said.
The estimated 5-million-year-old male walrus, named Waldo, has many scars, telling of many battles, Rivin said. “Walruses have a huge history here in Orange County,” she said.
Waldo also has a big deep jaw, which signifies he may have been a fish eater, she said.
“Waldo is one of our favorite fossils. In fact, we made him into our logo,” she said, adding that the walrus is about 98 percent complete. “He is probably the most complete walrus known anywhere.”
Some other fossilized remains found include: duck-billed dinosaurs, saber-toothed deer, sea cows, manatees, dugongs, seals, sea lions, hippos, whales, dolphins, sharks and the phoberogale, California’s first bear that is about the size of a raccoon, Rivin said.
Some of the fossils found throughout the county can be viewed at the Ralph B. Clark Interpretive Center in Buena Park. The museum is Orange County’s only paleontology museum.
Contact the writer: amarcos@ocregister.com
