Ranger Sarah has arrived at Agate Fossil Beds National Monument in Nebraska. Known for a large number of well-preserved Miocene fossils. Fossils from the Harrison Formation and Anderson Ranch Formation, which date to the Arikareean in the North American land mammal classification, about 20 to 16.3 million years ago, are among some of the best specimens of Miocene mammals.
Ranger Sarah has spotted a short-horned lizard, sometimes called the horny toad. Can you see it, it blends in perfectly with the rocks behind it. This little guy is commonly sited around the rocks near the Fossil Hills trail. Short-horned lizards are between two and six inches long with pointy spines on their head and body.
Ranger Sarah studies the trail sign for the 1 mile loop Daemonelix Trail. A Daemonelix are large spirals. At first thought to be the fossil remains of gigantic plants, they were later identified as the fossilized casts of spiral burrows made by ancient beavers called Palaeocastor.
— at Agate Fossil Beds National Monument.
Ranger Sarah learns about the ancient sand dunes. This 22 million year old sand dune is the oldest land form exposed in the Niobrara Valley. The sandstone is composed of fine volcanic material that were transported by the wind from volcanic areas in Utah and Nevada.
— at Agate Fossil Beds National Monument.
Ranger Sarah at strange corkscrew that was once know as the Devil's Corkscrew. The Daemonelix is the corkscrew entrance to the Palocaster's den. Palocasters were small ancient beavers that behaved like modern prairie dogs.
— at Agate Fossil Beds National Monument.
Niobrara River was to small to carve this valley area. River Terraces found in the area indicated that a larger, ancient river once flowed through forming the valley.
— at Agate Fossil Beds National Monument.