Agate Fossil Beds National Monument

Agate Fossil Beds National Monument was established June 14, 1997. The monument includes a valley of the Niobrara River and Carnegie Hill and University Hill. A large number of well-preserved mammal fossils have been quarried from sites on the two hills. Paleontologists have recovered some of the world's best preserved fossils of Menoceras, Moropus, and Dinohyus from the Miocene Epoch (roughly 23 to 5 million years ago). A special exhibit at the visitor center also chronicles the friendship between rancher James Cook and Lakota Chief Red Cloud.
The 2.7 mile Fossil Hills Trail runs from the visitor center to excavation sites on Carnegie Hill. There is about 250 feet of elevation gain. About halfway along Fossil Hills Trail a side trail leads to Bone Cabin, the homestead of Harold J. Cook, the son of James H. Cook (of whom we will talk later). The Harold J. Cook Homestead (Bone Cabin Complex) was listed on the National Register of Historic Places in 1977. I visited Agate Fossil Beds National Monument in June, 2025.

Significant Numbers

First Fossil Finds

Daemonelix Trail

The Daemonelix Trail is an easy one mile loop trail at the entrance to Agate Fossil Beds National Monument. The trail passes some interesting paleogeology before arriving at the Daemonelix exhibits. FYI a Daemonelix is a fossilized spiral burrow of the prehistoric beaver, Palaeocastor.

Daemonelix Trail

Ancient Dunes

22 million year old sand dunes

A Slice Through Time

I could only find 2 of the burrows in the photo

What a Daemonelix Is

Daemonelix

Split Daemonelix

Visitor Center and Museum

Agate Fossil Beds National Monument is located 25 miles south of Harrison, NE on NE Highway 29. The park and visitor center is open year round, although summer and winter hours are slightly different. There is no fee to visit the park. The visitor center houses the museum, special exhibits, restrooms, and gift shop.

Visitor Center and Museum

Teepees

Visitor Center

Scavenging

Mystery of the Daemonelix

Life and Death at the Agate Waterhole Diorama

Life and Death at the Agate Waterhole

The Agate Waterhole Actors

Daphoenodon superbus (Beardog) - carnivore of the early Miocene
Dinohyus hollandi - omnivorous mammal of the Miocene
Dinohyus was the largest of a group called entelodonts related to pigs
Moropus elatus - herbivorous mammal - Miocene
Morpus belonged to a group called chalicotheres related to horses, rhinos and tapirs

Miocene Epoch - 23 to 5.3 million years ago

Dinohyus hollandi

Daphoenodon superbus (Beardog)

Daphoenodon (left) Dinohyus (right)

Moropus Elatus

The James H. Cook Collection

In 1887 Kate Graham and her husband, "Captain" James H. Cook, purchased the Graham's 04 ranch and named it Agate Springs Ranch. Cook continued to ranch at Agate Springs until his death in 1942. He was very good friend with Lakota Sioux chief Red Cloud and was often visited by the Sioux and Cheyenne. He received many gifts as tokens of their friendship. These gifts are now priceless Indian artifacts that are curated in a collection at the Agate Fossil Beds National Monument museum.

Indian pictograph on animal hide

James Cook and Agate Springs Ranch

Gift Giving: A Lakota Tradition

Remembering the Battle of Greasy Grass

Battle of Greasy Grass Pictograph

Pipe Smoking: A Shared Ritual

More Exhibits

Background information obtained from Wikipedia, agatesprings.com, and National Park brochures.
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