Late Cretaceous (70 million years ago) Canada
Thescelosaurus (“beautiful reptile”) belonged to a group of relatively primitive plant-eating dinosaurs known as the hysilophodonts. These dinosaurs had bipedal posture and tall, ridged teeth for processing tough or fibrous plant tissues. Unlike the “duckbilled” dinosaurs, their more specialized relatives, this group had five fingers on the hands, relatively simple teeth, and a generalized skeleton.
Numerous dinosaur fossils have been found in Montana, Wyoming, and Utah, but few have been found in California. Dick Hilton of the Earth Science department has been looking for fossils for much of his illustrious career. Marine deposits in California’s central valley also include items that have washed off the land such as trees and cycads. Once while finding extinct ammonites in Mesozoic concretions he commented that someday someone would find a dinosaur here.
East of Red Bluff he found a concretion that when split open revealed bones. They could have been fish or turtle or marine reptile or maybe even a dinosaur. Next to it was a second concretion that contained more bones. It was a slow tedious process to remove the cement hard surrounding matrix and release the bones. When removed they turned out to be from a left foot, so they weren’t from a fish. They were not wide and flat like sea turtle or other marine reptile flipper bones. They were from a terrestrial animal. Eventually they were identified as being from a bipedal plant eating dinosaur, Thescelosaurus. It was about the size of a small deer.
A complete specimen had been found in Canada. Charles Dailey conducted a fund raiser to encourage the community to donate the price of a copy of particular bones. Dailey bought the middle finger for Hilton. Frank DeCourten took on the task of assembling the skeleton. It was reconstructed in a posture of fleeing from the T. rex whose skull replica is mounted above and behind it. Since then Dailey found a place in eastern Montana where dinosaur bones occur in soft sediment. Field paleontology classes have made several trips there collecting specimens that are displayed in the floor cases in the northeast foyer.
Pat Antuzzi, a local fireman, found the first evidence of a meat-eating dinosaur near by in Granite Bay.
One of our “hands-on” displays is this leg bone (left tibia) of a Camarasaurus sp. from the Morrison Formation. Camarasaurus was a large, 60 ft (18 m) long sauropod or plant eater. This bone is approximately 145 million years old. It was found in the Brushy Basin Member near the San Rafael Swell, Utah. It was donated by Robert Mitcham.
Another "hands-on" display is the tibia/fibula (shin bones) and radius (forearm bone) of a sauropod dinosaur, Apatosaurus. This was once known as brontosaurus. It is from the late Jurassic and is about 150 million years old. When alive it could have been up to 70 feet long and 33 tons in weight. These bones were found in the Morrison Formation in Utah. These bones were donated to the Musuem by Robert Sowell in 2003.
Several dinosaur specimens have been found on Sierra College field trips. There are two skulls on display here. A Pachycephalosaurus skull and a partial Triceratops skull, both found at the Fort Peck Reservoir in Montana. More about this display is here.
Other dinosaur fossils on display include several theropod vertebrae, Triceratops vertebrae and jaw bone, Stygimoloch skull fragment, Hypsilophodont toe claw, Ornithomimid foot and claw bones, Hadrosaur jaw, hoof and fibula. We also have on loan from the California Academy of Sciences a large theropod footprint and life-size replica of a Tyrannosaurus rex skull.
Sierra College usually offers a geology/biology field trip class to Montana every three years in the summer to search for fossils with a federally required fossil-collecting permit. Begin your paleontology career with Sierra College!