Guidebook—Geology and Paleontology of Northwestern Kansas
Outcrop of Niobrara Chalk, Gove County.
Stop 4 to Stop 5
As we leave the Smoky Valley Ranch, we will travel north and then head east into Gove county, crossing U.S. Highway 83. Travelling east, we pass through a crossroad known as Orion and the town of Gove. From the point where we turn east in Logan County, the high point of our trip topographically, we travel on the High Plains surface, but drop 570 feet in elevation by the time we cross Hackberry Creek near our fossil-collecting site at Stop 5.
Stop 5--Fossils in the Niobrara Chalk
Because of the value of large vertebrate fossils, and because of the popularity of fossil collecting in western Kansas, landowners here are particularly sensitive about fossil collecting on their property (see section on legal issues). Out of respect for the landowners who have been considerate enough to allow us onto their property, we will not be describing this site in any detail and we ask participants to bear in mind the following:
- The Kansas Geological Survey has received permission from the landowner for participants to collect fossils. That permission applies only to this trip, however, and does not constitute permission to return to this location for future visits. Failure to obtain permission from landowners for any future visit would make you liable to prosecution for trespassing, and may mean that landowners will not allow future field trips to visit this site.
- If you find fossils that you believe are particularly unusual or valuable, we ask that you provide that information to the landowners. Then you and the landowner can determine how such fossils should be recovered and where they should eventually reside.
Note: Watch out for rattlesnakes. Local residents have lots of stories about the number of rattlesnakes they've seen in these canyons. While you walk through the chalk beds looking for fossils, or when you turn over rocks, keep an eye out for snakes.
Fossils in the Niobrara Chalk
As we've already mentioned, the Smoky Hill Chalk Member of the Niobrara Chalk is world famous for its well-preserved and scientifically significant fossils. The first vertebrate fossil collected from the chalk was found by Capt. Theophilus H. Turner, the post surgeon at Fort Wallace in the 1860's (Almy, 1987). Turner discovered the remains of a plesiosaur, a large swimming reptile related to the mosasaur. Other collectors soon uncovered additional remains of the vertebrate and invertebrate animals that lived in the vast inland sea that covered Kansas during the Cretaceous Period, some 80 million years ago.
The Cretaceous Period was part of the Age of Reptiles, an era famous for its dinosaurs. Although dinosaurs were restricted to landmasses far from western Kansas, their marine cousins--mosasaurs and plesiosaurs--roamed the seas. Besides these large marine reptiles, huge turtles, sharks, flying reptiles, and toothed-birds also inhabited the area and their fossils have been found in the chalk.
Sharks' teeth and the remains of fish (teeth, vertebrae, bones, and scales) are found at almost all chalk exposures in the region. In general, however, vertebrate fossils are less common than the remains of invertebrates, creatures without backbones.
Probably the most common invertebrate fossils in the chalk are clams and oysters. In fact, the largest clams known, the inoceramids, come from the chalk beds of western Kansas. These extinct clams, some of which had shells with diameters of 6 feet, lived in colonies on the sea floor of the shallow Cretaceous ocean. Great numbers are preserved in the Niobrara Chalk. Some of these huge fossils are covered with encrusting oysters (see photo below). Others have been found with a variety of fish fossils between their shells, indicating that the fish used the giant clam as a safe feeding place.
This inoceramid clam shell, covered with the shells of encrusting oysters (Ostrea), was collected in the Niobrara Chalk of Trego County, Kansas.
The crinoid Uintacrinus is another noteworthy fossil found in the Niobrara Chalk. Crinoids are echinoderms, relatives of starfishes and sea urchins. Most crinoids have a cluster of segmented arms that sits on top of a long stem, but Uintacrinus is different. This spectacular and rare fossil is a stemless crinoid and entire specimens have been found in the chalk. Because Uintacrinus occurs in thin layers and weathers easily, finds are rare; one locality for this fossil is Blue Knob at the Smoky Valley Ranch Preserve.
Uintacrinus socialis is a stemless crinoid that lived in the Cretaceous seas that covered Kansas roughly 80 million years ago. Among the numerous segmented arms preserved in this slab, a segmented calyx is also visible. This slab was collected in the Niobrara Chalk of Gove County.
Ammonoids, extinct squidlike creatures that lived inside an external shell, are also fairly common in the Cretaceous chalk. Ammonoids are relatives of the modern squid as well as the octopus and chambered Nautilus, all of which belong to the class of animals called cephalopods.
Specimens from the Kansas Cretaceous are exhibited in museums around the world. Some of these include the Smithsonian Institution in Washington, D.C., the American Museum of Natural History in New York, the Denver Natural History Museum, and, here in Kansas, the Sternberg Museum of Natural History in Hays, the KU Natural History Museum in Lawrence, and the Fick Fossil Museum in Oakley.
Stop 5 to Oakley
Following Stop 5, we proceed north and west to the town of Gove. According to the 2000 census, Gove has a population of 105, making it the smallest county seat in Kansas. Some Gove County facilities and offices have been moved to Grainfield in the northern part of the county, which is larger (population 327) and located on I-70.
From Gove we head north to I-70 at Grainfield and travel west, climbing 500 feet to our starting point in Oakley.
Almy, K. J., ed., 1987, Thof's Dragon and the Letters of Capt. Theophilus H. Turner, M.D., U.S. Army: Kansas History, v. 10, no. 3, p. 170-200.
Blakey, 2001, Late Cretaceous Paleogeographic Globe: Regional Paleogeographic Views of Earth History, http://jan.ucc.nau.edu/%7Ercb7/Late_Cret.jpg, October 1, 2002.
Bonner, L., 2002, Keystone Gallery--Art, Fossils, and Curiosities in Western Kansas (October 7, 2002).
Kansas Department of Wildlife and Parks, 2005, Scott State Park, http://www.kdwp.state.ks.us/news/state_parks/locations/scott, May 2005; also see Lake Scott State Park and Wildlife Area brochure.
McCauley, Jim, Buchanan, Rex, and Sawin, Bob, 1997, Fossil Collecting in the Cretaceous Niobrara Chalk--Kansas Earth Science Teachers Association, Sixth Annual Field Trip: Kansas Geological Survey, Open-file Report 97-62, 14 p.
Sawin, Robert, McCauley, Jim, Buchanan, Rex, and Lebsack, Wayne, 1999, Smoky Valley Ranch Preserve Geologic Reconnaissance: Kansas Geological Survey, Open-file Report 99-36, 6 p.
Wicander, R., and Monroe, J. S., 1989, Historical Geology--Evolution of the Earth and Life through Time: St. Paul, Minnesota, West Publishing Company, 578 p.
This guidebook is also available in print form as Kansas Geological Survey, Open-file Report 2002-42, from KGS Publications Sales office, 785-864-3965.
Unless noted otherwise, illustrations by Jennifer Sims, Kansas Geological Survey; photographs by John Charlton, Kansas Geological Survey. Text by Liz Brosius, Jim McCauley, Bob Sawin, and Rex Buchanan, Kansas Geological Survey.
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