GSM 2017 Nebraska Day 7 Part 2
Oct 4, 2017Public
Photo: This map shows the last sites we visited in Nebraska: Agate Fossil Beds and Toadstool Geological Park. Many of us camped that night in Chadron State Park.
Photo: In Agate Fossil Beds National Monument, we first walked the Daemonelix Trail.
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Photo: The one-mile Daemonelix Trail at the west end of the park offers visitors a tour through through time. In addition to a dry land beaver's curious spiral burrows, the Daemonelix or Devil's Corkscrew, visitors see ancient sand dunes and fossil grassland soils called paleosols.
Photo: A patch of plants with ripe burs along the trail.
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Photo: Ancient sand dunes
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Photo: The cliff face described in the previous photo.
Photo: In the center is part of a daemonelix (devil's corkscrew).
Photo: Yucca glauca is a species of perennial evergreen plant, adapted to xeric (dry) growth conditions. It is also known as small soapweed, soapweed yucca, Spanish bayonet,  Great Plains yucca and beargrass. Yucca glauca forms colonies of rosettes. Leaves are long and narrow, up to 60 cm long but rarely more than 12 mm across. Inflorescence is up to 100 cm tall, sometimes branched sometimes not. Flowers are pendent (drooping, hanging downward), white to very pale green. The fruit (seen here) is a dry capsule with shiny black seeds.
Photo: Note the enclosure at lower left protecting a well-preserved devil's corkscrew.
Photo: The basic form of the daemonelix is an elongated spiral of hardened earth material that inserts into the soil as deep as 10 feet.
Photo: The Devil's Corkscrew being the result of the burrowing of a Palaeocastor (prehistoric beaver) was not universally accepted in the scientific community as late as the second decade of the 20th Century. The dispute on its real identity ceased when a fossilized beaver was discovered in one of them. The scratches which were previously misinterpreted as claw marks are also strong evidence of the existence of Palaeocastor in contrast to a modern beaver. They excavated their burrows with their incisor teeth, not their claws.
Photo: From the number and concentration of their now petrified homes, paleontologists know that the paleocastor, the dry land beaver, formed and lived in colonies much like present-day prairie dogs.
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Photo: From the Deamonelix Trail's highest point, visitors can look out over not only James H. Cook's historic Agate Springs Ranch but also the vast, open tablelands that form the northern terminus of the High Plains east of the Rocky Mountains.