Paleontology in the Wildcat Hills : Highway Paleontology Program : Science & Culture | Vertebrate Paleontology : Collections & Research : University of Nebraska State Museum of Natural History

< Vertebrate Paleontology Home

The Highway Paleontology Program is a partnership between the University of Nebraska State Museum and Nebraska Department of Transportation.

Highway Salvage Paleontology in the Wildcat Hills: Life in the Past Lane

Forty years ago, legislation mandated the salvage of fossil remains threatened by highway construction. Nebraska introduced the country’s first paleontological salvage program (see Oct./Nov.,1996 Roadrunner) which is based on close cooperation between contractors, the Nebraska Department of Roads (NDOR), and the University of Nebraska State Museum (UNSM). In areas where new construction threatens paleontologically sensitive areas, such as the Wildcat Hills south of Gering, museum paleontologists follow a basic three-phase strategy to recover the maximum amount of scientific information without causing construction delays.

View north prior to construction. The diagonal line in the road cut is the geologic contact between the 20 million-year-old river channel and the underlying 28 million-year-old Gering Formation. This cut produced a treasure-trove of fossils during construction.

Phase 1: Pre-Construction Salvage

Early notification of the proposed upgrade of N-71 allowed us to survey the large roadcuts made during the original alignment and collect vertebrate fossil specimens exposed by erosion. Several beautifully preserved, articulated skeletons of the sheep-like oreodont Merychyus, a camel, and a small deer were excavated, however the most important discoveries were tiny teeth of mouse-size critters. Sixteen different small-mammals including a new species of gopher were recovered from over a ton of gravel screened on site. The fossils indicated these rocks were deposited by an ancient river over 20 million years ago.

Phase 2: Salvage During Construction, 1999

View north prior to construction. The diagonal line in the road cut is the geologic contact between the 20 million-year-old river channel and the underlying 28 million-year-old Gering Formation. This cut produced a treasure-trove of fossils during construction.
Clarence Millikin, dozer operator for Platte Valley Construction, became an invaluable resource during the excavation process. Clarence cut trenches that showed the local geology, removed unfossiliferous overburden exposing the fossil-rich portions of the river channel, and removed piles of excavated sediment. His skill saved the scientific crew untold hours of back-breaking work, and allowed them to concentrate on collecting fossils and documenting the site.
Platte Valley Superintendant Dennis Giesman (left), Clarence Millikin (center) and Steve Dieriex pause to observe the discovery specimen, the lower jaw of a clawed horse-like animal. By following this one-lane path (note tire tracks), the dirt crew was able to complete this portion of the project well ahead of schedule while paleontologists salvaged the entire bone bed.
After the discovery of numerous bones along the back slope, Highway Paleontologist Bruce Bailey (left) and Project Manager Joe Applegate discuss the possibility of future excavation. Joe and Craig Lind provided invaluable assistance throughout the salvage operation.
Monte Wegelin, Nebraska Department of Roads employee (left), volunteered his free time to help excavate the site. Monte was a natural "fossil-finder" and discovered many unique specimens.
Monte Wegelin slowly scrapes away sand and gravel exposing numerous bones in his excavation square. The arrow points to the lower jaw of a tapir that he discovered. Tapirs, generally quite rare as fossils, were among the most common animals found during the 1999 excavation.
This chalicothere jaw was the initial discovery specimen. Chalicotheres are clawed horse-like animals that have been found in large numbers at Agate Fossil Beds near Harrison, Nebraska.
The lower jaw of an anthracothere, wedged up against the bank of the ancient river. Anthracotheres were bizarre hippo/pig-like creatures that are fairly common in this 20 million-year-old river deposit.
The lower jaw and leg bone of an early bear.
Craig Lind, Nebraska Department of Roads District 5 Construction Engineer, gives the final okay to remove the spoil piles and finish the backslope, ending the 1999 excavation. The cooperation between the Nebraska Department of Roads, Western Engineering, Platte Valley Construction, and the University of Nebraska State Museum allowed the excavation to run efficiently and finish well ahead of schedule.
Greg Brown, University of Nebraska State Museum Chief Preparator, uses a scalpel and paint brush to uncover the lower jaw of a sheep-like animal called an oreodont. The specimen has been pedestalled and is nearly ready to have a field jacket of plaster and burlap applied so that it can be safely removed.

You might think heavy equipment and fragile fossils is a combination to be avoided. Quite the contrary! In vast areas of hard rock, bulldozers and scrapers are the most efficient means of discovering new fossils. Searching through large sandstone blocks left in the wake of D-9 ripper-cats we collected partial skulls of three rare mammals, found for the first time in these deposits; the four-horned deer Syndyoceras, a tapir, and a hippo-like anthracothere. As the fleet of a dozen scrapers neared grade to the north, they uncovered a veritable treasure-trove of fossil bones. Platte Valley Construction Superintendent Dennis Giesman instructed his crews to work around this area while we resorted to the more conventional tools of our trade; namely shovels, trowels and paint brushes. During the next month, the entire bonebed was excavated from median to backslope with phenomenal results; over 200 specimens were collected, a third of which were skulls or jaws!

This site is scientifically important for many reasons. Rocky Mountain gravel discovered near the bottom of the channel indicates a major, through-flowing river deposited the sediment. Petrified logs were common, suggesting a heavily forested valley. The fossil mammals represent a unique "jungle fauna" composed of a great variety of low-crowned browsing herbivores and the carnivores that fed upon them. It is the only locality of this age in the Wildcat Hills that has produced a significant vertebrate fauna. For this reason District Engineer Tim Weander granted permission to continue this excavation after highway construction was completed.

Phase 3: Post-Construction Salvage, 2000 and beyond

Bruce Bailey records the area geology in his field notebook and maps the positions of all the fossil specimens before they are removed from the ground. Accurate data collection of this sort is absolutely essential.
A block of associated anthracothere bones ready for jacketing. Concentrations of bones like this occur when river currents slow or obstacles in the stream create natural "traps" or eddies where heavier bones and debris settle to the bottom.
Local students assist Shane Tucker, Highway Salvage Preparator, as he applies a plaster and burlap field jacket to a complete turtle specimen. Numerous other specimens (foreground) have already been jacketed and mapped and are ready to be removed. A five foot section of fossil log (left foreground) was also discovered in this excavation square.

In the spring of 2000, the backslope was reopened and excavated throughout the summer with equally astonishing results. Several jaws of an ancestral bear, an extremely rare weasel, and a new genus and species of large beaver were highlights of the second season. Thus far, 20 different large mammal species have been identified from this site. The combined total of 36 large and small mammals make it the most diverse fauna of this age in the Great Plains.

Acknowledgments

We would like to thank the Nebraska Department of Roads (Transportation), District 5, Western Construction Company, and the University of Nebraska State Museum for their assistance throughout the project. Without their cooperation, a salvage operation of this magnitude could not have been successfully completed.