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Dinosaurs and More in California

What do tiny trilobites, swift-footed dinosaurs, and huge shaggy mammoths have in common? They are each a part of the fossil record in California.


Up in Northern California, in Shasta County, ancient dinosaur bones have recently been found. These bones are the oldest known record of dinosaur life on the Pacific Coastal areas of the United States and date from 115 million years ago.

Before this dinosaur was found in 1991, it was not widely believed that there had been much of any dinosaur life in California during the Mesozoic Era, 225-65 million years ago. Only a few other sites have revealed dinosaur bones in California - San Diego, Fresno, and Riverside. The recent 1991 discovery was in Shasta County, the northern reaches of the California Backcountry, and has sparked interest in the possibility that there might have been much more dinosaur life in the state than was previously believed.

The Sierra college professor who found the fossils is Dick Hilton, and working with fellow geologist ( yes, paleontologists often start out as geologists and get hooked on the bones they find ) Frank DeCourten in 1993,who was a dinosaur expert from Utah, they found remarkable similarities immediately between the Shasta fossil and those from Utah that DeCourten had been working with. What they learned was that 115 million years ago a swift footed, deer sized - hypsilophodont - dinosaur, walking on it back legs, roamed the heavily forested northern mountains of what is now California. He had short little front arms and hands that were dexterous enough to gather plant food (he was an herbivore), and probably looked something like the picture you see here.

Surf the Sierras ?

Many millions of years ago, before the California coastal ranges rose to be the mountains we can see today, the ocean stretched inland all the way to the foothills of the Sierras. Yes, you could have surfed to the Sierras in those times!

Seashells from ancient seabeds - like the spiral ammonite, clams, oysters - and sharks teeth - have been found in the Sierra foothills. What is now the gateway to the backcountry for us, was once the beach is Mesozoic times.

Like the sea shell fossils that sank to the bottom of the sea and were covered with hundreds of thousands of years of preserving soil, the skeletons and bones of land animals were washed out into this same sea, sank to the bottom, and also were covered by the same types of silt and soil that preserved them for our study today.

Sea Life in the Fossil Record

In the backcountry of Santa Barbara County, one can find entire stretches of seashells imbedded in the cliff side and tumbling out into the trail. It is amazing enough to consider that at one time the coastal mountains you can stand on today did not even exist, but were instead a flat ocean bottom covered by hundreds of feet of water. It is even more astounding to then realize that this same sea once lapped up along the foothills of the Sierras, which were then a much younger mountain range than today.

The seashells that can be found in the Backcountry are often bi-valve clams, and up north in the Red Bluff area, there are very beautiful spiral ammonites found. These shells tell us of a time when the ocean levels were much different than they were today, a time when people did not yet roam this part of the world as far as we know. A time when California was not just wilderness, it was primeval forest and sea.

Remote Island Fossils

On the remote California Channel Islands an interesting cross section of mammal fossils have been found. We will study with some detail the mammoths, but consider this largest list of mammal fossils that have been found on the islands:

An extinct species of vampire bat
An extinct flightless goose
Gopher snakes
Now extinct giant mice
Sea otters
Unique to the island - and extinct - pygmy mammoth
Now extinct giant mammoths.

And in the reverse, it is interesting to note that a type of ironwood tree found in rare locations out on the islands, is now known only by the fossil record on the mainland. This is all the beginning of exploring the science and history of the California Backcountry.

Now take the Paleo Quiz