Fossils at the Frehner Museum

During the tectonic plate shifts while the continents were forming, Utah found itself in and out of the ocean. This provides an interesting variety of fossils, ranging from small sea shells to dinosaurs, which have been discovered by archeologists in Utah dig sites. Here is a small sampling of the different kinds of fossils you can see in our museum, some of which date all the way back to the Middle Silurian Period, approximately 425 million years ago.


Our museum’s biggest ammonite fossil comes from Texas, and measures 16 inches wide. It is from the Upper Cretaceous Period, which was about 65 million years ago. Ammonites are an extinct relation to cephalopods, which include octopuses, squid, cuttlefish, and nautiluses. Ammonites were essentially squids living in a coiled shell. Their name derives from the Greek word Ammon, for the Egyptian god Amun. Amun was known as the "King of the Gods" during the height of Egyptian civilizations and was often depicted with a ram's head and horns. Ammonites were considered sacred to the early northeastern African people because of their ram's horn shape and its association to their god.

Stenophlebia latreillei

This is definitely a fossil that should be seen in person. Discovered in Solnhofen, Germany, this dragonfly fossil is dated from the Jurassic Period, approximately 150 million years ago. Fossils of dragonflies are very rare because their bodies, especially their wings, are so lightweight. It is hard to get a good impression of them and have that impression remain intact for millions of years. The Stenophlebia is an extinct genus of dragon-damselfly. Dragonflies were some of the first winged insects to evolve over 300 million years ago. Dragonflies catch their food while flying, grabbing their prey with their feet. These expert fliers can fly straight up and down or hover like a helicopter. Engineers study dragonflies in hopes of creating robots that can mimic the way they fly.

Lepisosteus cuneatus

This specimen was found near Soldier Summit, Utah. The gar fish name comes from the Anglo-Saxon word for spear. They are often called garpikes because of their narrow and elongated mouths. Gars are still alive today and are often called the living fossil because they have remained relatively unchanged since prehistoric times. A gar fish can live up to 20 years, grow up to 3 meters (9.8 ft) long, and weigh up to 300 lbs. Their diet consists of smaller fish, and there are no recorded incidents of gars attacking humans.

One characteristic that has helped this species survive for hundreds of millions of years is their capability to live in very harsh water conditions. They gulp air and store it in what is called a swim bladder. This helps them survive in low-oxygen conditions where normal gill breathing would not be effective or sufficient. They are primarily freshwater fish and used to have a near global distribution, but today are only found in North America.

Dilophosaurus Eubrontes

Eubrontes is a fossilized dinosaur footprint. It is named for the shape of the fossil, not the genus of the species that made the print. The Eubrontes in our museum was made by a Dilophosaurus and was found at the St. George Dinosaur Discovery Site.

The Dilophosaurus, Greek for “two-crested lizard,” dates back to the Jurassic Period, about 193 million years ago. It was one of the largest carnivores of the time, measuring 6 meters (20 ft) long and weighing up to 1,100 lbs. The Dilophosaurus’ most distinctive trait is the pair of rounded crests at the top of its skull.

Petrified Pinecone

Our museum has a petrified pinecone that is about 10 inches long. This specimen was formed through permineralization, the same process that creates petrified wood (which can also be found in our museum).  Permineralization occurs when minerals replace all the organic material of a tree or plant. For this to happen, the plant has to be buried underground, where the lack of oxygen preserves the plant structure. Then, water carries mineral deposits which fill the plant’s structure, forming a stone mold as the plant cells decay.

This page was updated November 2019.