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Ancient fossil discoveries abound in and around Southern California

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Imagine beachfront property in Denver, Colo.

That’s about the closest dry place, if one were reading this article 65 million years ago. It doesn’t matter where in Southern California you’re located; the entire landscape was submerged at least 550 to 800 feet under the sea when the “K-Pg” extinction boundary event (the earth-altering meteor that slammed into the Yucatan Peninsula, marking the boundary between the Cretaceous and Paleocene periods) along with millions of years of ferocious volcanism that spelled doom for the dinosaurs.

Outside of a museum display, Southern California won’t yield any trace of a brachiosaurus, stegosaurus or tyrannosaurus; fossil remains of these famous land dwellers are found primarily in the “Badlands” of Montana, in North and South Dakota and in Utah. Up and down the Golden State, however,  paleontologists, geologists and just plain fans of earth history stretching back 500 million years can find a treasure trove of fossilized sea creatures, plants and, once in a while, even the stone-imbedded remains of a hadrosaur (”duck-billed” dinosaur).

Most of what paleontologists find today stems from the Miocene Era 12 million years ago when the Los Angeles Basin was completely submerged in water. In fact, not only did the Pacific Ocean cover Los Angeles, but the town was in a completely different geographic location—about 10 to 145 miles to the southeast. That’s why scientists continually uncover marine fossils—some of the earliest of which lived in water up to one mile deep.

Marine specimens found locally

While Southern California won’t yield many fossils from the big herbivores and carnivores that dominated earth for 190 million years during the Mesozoic Era (beginning 250 million years ago and comprising the Triassic, Jurassic and Cretaceous periods), Alameda County to the north is considered by experts as a “gold mine” of Cretaceous- and Miocene-era fossils. They’re mostly sea creatures like ammonites (extinct, “flat-shelled”  cephalopods of the Mesozoic Era) and prehistoric plant life. The same can be said of Butte County, in Contra Costa and in the Coalinga area within Fresno County.

For decades, many varieties of clams and oysters dating from the Cretaceous Period have been discovered at Coyote Wells in Imperial County. Sponges from the Cambrian Period (the famous “Cambrian Explosion” 540 million years ago that resulted in thousands of species of sea life) are found regularly in Inyo County, while rare corals emanating from the Carboniferous Period (350 million years ago and labeled the “Mississippian/Pennsylvanian” in the Western Hemisphere) have also been unearthed in the region.

Last year, the San Jose Mercury News reported that more than 500 marine fossil specimens had been uncovered at the Calavaras Dam replacement project in Fremont. Most of the fossils are believed to be about 20 million years old dating to the Miocene Ephoch when the Fremont region extending as far south as Bakersfield was submerged in  water. Scallops, clams, barnacles and the teeth of an extinct hippopotamus-like creature called a desmostylus have all been unearthed.

Paleontologists there are continuing their work with construction workers who are building a new, “earthquake-proof” dam. Among the fossils ultimately discovered were giant teeth from a 40-foot shark and portions of what may turn out to be an entire whale skeleton.

Thousands of marine fossils were discovered in 2000 during the construction of the Metro Red Line subway in Los Angeles. Most of the findings date back 7 to 8.5 million years and are believed by experts to represent the most diverse fish fauna collection ever reported from the late Miocene period. About 3,000 marine fossil specimens, representing some 100 species, date from the Miocene (25 million years ago) and the late Pleistocene (10 million years ago) era. Some of the fossils are displayed at the George Page Museum and La Brea Tar Pits and provide researchers with a glimpse of Los Angeles during the Ice Age when the L.A. Basin was a brush-covered plain where animals such as mastodons, bison and camels roamed freely. Some of these finds include ancient smelt, specifically “deep sea smelt,” similar to what can be found today living at depths greater than 1,000 feet.

Cretaceous era fossils in Woodland Hills

Ammonites from the Cretaceous Period have been found in Woodland Hills and also in portions of the Santa Monica Mountains, the latter area also revealing a collection of  marine vertebrate bones from the Miocene era. Marine fossils from the Cretaceous era have been discovered in southern Orange County; Ladd Canyon in particular has revealed corals and gastropods dating to the Carboniferous Period. Further east in San Bernardino County, actual dinosaur tracks have been discovered in the Mountain Pass area and date from the Jurassic Period.

The California topography has revealed rare discoveries of Cretaceous-era reptiles, such as fossil fragments of a plotosaurus (“flat lizard”) in Merced County, while the Pt. Loma region of San Diego County has been the sight of the discovery of a number of species of cephalopods dating back at a minimum 90 million years exposed within its granite outcroppings.

Researchers affiliated with the Natural History Museum of Los Angeles County agree that a few dinosaur remains have been found in California. These animals would have lived in a violent world where volcanic eruptions continuously shook the land, darkening the sky and sending streaming mudflows surging through canyons. Because dinosaurs were land-dwelling animals, the infrequent dinosaur fossils found in the state probably originated to the east (in Arizona and New Mexico anywhere from 225 to 66 million years ago) and were washed out to the ocean where they were deposited on the sea floor. Retreating seas and coastal uplifting created the land that was to become California. Weathering and erosion then exposed the buried fossils found primarily in inland areas of the state.

Dinosaurs in Carlsbad?

Experts agree that the largest collection of dinosaur fossils ever found in Southern California were unearthed in 1987 in Carlsbad. Paleontologists at the San Diego Natural History Museum believe that the dinosaur—estimated to be 15 feet long—may be the first of its kind found west of the Rocky Mountains. They based their theory on a single tooth taken from the site; the leaf-shaped tooth is reported to be common among nodosaurs (a group of armored dinosaurs), the pachycephalosaurus (the “bone head” dinosaur depicted in the 1997 film “The Lost World: Jurassic Park”) and another terrestrial dweller, the thescelosaurus, which was a small, bipedal dinosaur. The Carlsbad discovery was only the fifth instance of dinosaur fossils being found locally, the only other being a piece of a jawbone (the original owner still unknown) found decades ago in the Santa Ana Mountains in Orange County. A few years before the Carlsbad discovery, researchers dug out the fossilized bones of two other hadrosaurs—a leg bone and a neck vertebrae—in almost the same location. In the 1987 discovery, scientists believe that this dinosaur lived 70 million years ago during the late Cretaceous Period.

Millions of film fans this weekend will probably see a giant carnivorous sea creature (a mosasaur, according to paleontologists) launch itself out of a Sea World-like enclosure and gobble up a Great White Shark in Steven Spielberg’s latest dinosaur flick, “Jurassic World.” There were many groups of marine organisms that roamed the seas from the Jurassic through the Cretaceous periods. The Department of Paleobiology at the Smithsonian Institute has reported that sharks of all kinds once abounded in prehistoric seas, as well as a type of aquatic marine lizard—the aforementioned mosasaur—in which some species reached over 14 meters in length. Equally dangerous and just as large were plesiosaurs (such as kronosaurus) and huge crocodiles, but experts contend that the later sea carnivore was less common during the last days of the dinosaurs. Another sea predator, ichthyosaur, once dominated the Triassic and Jurassic oceans, but had all but disappeared by the early Cretaceous.

Hollywood’s take on dinos

Reptiles were not the only marine giants of the Cretaceous. Strange-looking, often gigantic Rudistid clams reached up to one meter in length and formed extensive reefs in shallow tropical oceans. Another species of ancient clams, Inoceramids, have been discovered in some of today’s mountainous regions of California; some of these giant clam fossils measure more than three meters long. These organisms once thrived in the shallow, warm seas, including environments that were nearly devoid of oxygen. Various ammonite cephalopods (similar to modern octopuses, cuttlefish and squid) have been discovered in California; some of these fossils measure up to two meters in length.

What do the experts think of “Hollywood dinosaurs”? Most discount the depictions seen in such movies that have fascinated audiences since Godzilla took his first stroll in Tokyo in 1954. Hans-Dieter Sues, curator of vertebrate paleontology at the National Museum of Natural History in Washington, D.C., believes the re-creations—even the latest ones depicted in theaters for the next few weeks—are “out of touch” with scientific findings.

“The mosasaur in the pool (in “Jurassic World”) is twice the size of the largest actually known species,” Sues said. “Plus, it should have a forked tongue. In the movie, it doesn’t. The frill on its back shouldn’t be there, either. But the film did get one thing right about this marine reptile: its teeth. It had several rows of extremely sharp teeth, likely used to kill and eat large sea creatures such as a plesiosaur.” Sues also said the velociraptors depicted are “way too large” and should have had feathers.

Jack Horner is among the world’s foremost paleontologists. As curator of paleontology at the Museum of the Rockies as well as regents professor of paleontology at Montana State University, Horner is usually the “go-to guy” for any film about dinosaurs. He has suggested that some of the speculation about dinosaurs in the “Jurassic Park” franchise may ring true. He also credits the popular films for attracting more young people to the field of paleontology.

“Until the book [Michael Crichton’s 1993 science fiction novel] and the resulting movie, most of my graduate students were guys; afterwards it’s been about 50-50,” said Horner who served as an advisor for two of “Jurassic Park” films. “And, I never gave serious thought about ‘making’ a dinosaur until we made ‘Jurassic Park.’ When we started delving into getting DNA out of dinosaurs and failing at that, and then I got to thinking that there was a way to do it … you just had to use their descendants, the birds.” Horner added that new technology and methods of excavation have made it an “exciting time” to be in paleontology. “Kids are always fascinated by dinosaurs, and maybe some of this new technology and teaching methods (i.e. S.T.E.M.) will get them interested in not only paleontology but in genetics as well.”

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