10
Thursday, August 28, 1975
University Daily Kansan
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PXL Sound
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Staff Photos by DAVID CRENSHAW
Caught in a trap
Bv DAVID BARCLAY
Staff Writer
in the foothills of the Bighorn Mountains in Wyoming, perhaps about 50,000 years ago, during the Pleistocene Era, the roof of a dome-shaped limestone cavern collapsed, leaving a 13-foot opening in the earth's surface.
Located on a narrow strip of rock between two shallow canyons, where it was created became a natural drip trap for the animal.
Running animals or predators chasing their prey approached the hidden opening on an inclosed slope, and as they bounded over the ridge they would often disappear through the mouth of the trap.
For the last two summers, a group of about seven University of Kansas faculty members and graduate students have joined about 15 other scholars in making expeditions into the cavern.
Today, the trap is one of the best sites in the United States for excavating the fossilized remains of prehistoric animals, both in terms of quantity and quality of fossils. Dr. James Martin, curator of the KU Museum of Natural History.
The smell of rotting flesh lured other animals to the brink of the opening, through which the curious and daring were found.
Although it isn't as big, the trap is comparable to the famed La Brea Trap in Los Angeles, he said.
The trap is located 35 miles northeast of Lovell, Wyo., two miles from the Woming-Montana border.
Because of the distance the animals fell before striking the bottom of the cavern, many of their bones were fractured. The impact of new victims further damaged the skeletons of previously fallen animals.
Martin calculated that a mammmoth would strike the cave floor with a force of 860,000 foot pounds of pressure.
B. Miles Gilbert, a research associate in archaeology at the University of Missouri at Columbia, was the chief archaeologist at the site.
He said that apparently there had been a pile of rock and animal carcasses directly below the opening of the trap. When new victims struck the pile of rocks, they would have been exposed to the sides of the cave. This would explain the presence of fossils around its outer edges.
Gilbert estimated that there might be as much as 30 feet
of deposits in the cave floor, making the fossils on the bottom perhans as old as 50.000 years.
Until the summer of 1974 when a joint KU-Missouri team began the first significant excavation of the cave floor, the only way to enter the trap was to rappel down through the cave. A trapping system had been designed to the workers, temporary scaffolding was erected.
During the summer of 1974, over 2,000 specimens were excavated. Most were from 12 to 13 thousand years old.
This summer, seven KU faculty members and graduate students returned to the excavation to work for seven weeks on the cavern floor. Those who returned to work in the numbing 40 degree temperatures at the site included Andrew Peterson a KU vertebrate analyst and colleague coordinator of the xxhiii, and Orville Bonner, a KU paleontologist.
Martin said that if they could piece one of the mammoths together, it would be placed on display in the museum in Hainesville.
Excavations began at random locations on the cave floor, which measures 150 by 180 feet, until productive areas were located. The team members worked in five-foot-square areas, digging down six inches at a time. All of the bones they found were kept together in hopes they could be pieced together later.
Among the treasures that it yielded were the bones of camel, bison, tule wolf and wolvereine, bighorn sheep, antelope, elk and moose.
As the generator that powered the lights for the workers droned on the surface, the team members laid on their sides and stomachs, picking at the earth with trowels, ice picks and whisk brooms.
More than 10,000 specimens were excavated this summer, he said. The collection would be brought to KU, because some of the collection was lost.
Gilbert said he didn't think the team should excavate the entire cave.
One particularly important find was a cheetah-like cat never found in North America, Martin said. Two kinds of horses, a large and smaller variety, were the most frequently found animals.
enlarged care.
"I would rather leave a third or half of it for 200 years," he said, "and let somebody work on it then when they have better technology."
With an outside opening of only thirteen feet, nearly all of the 150 by 180 foot cavern is immune to weather and the elements. Most of the specimens brought out of the trap are well preserved, but
damaged by the 80 foot fall that brought them into the trap. The most productive areas of the cavern floor are those surrounding the scaffolding, directly below the trap entrance.
At the camp the smaller pieces were cleaned, and the larger ones were sewn together. In larger small, few were enveloped to be filled later.
All of the dirt removed from the 5 foot x 5 foot work areas was lifted through a wire screen to sort out the smaller bone fragments. The area location of the square and the depth the dirt was removed was recorded and the sifted material sent back to camp.
B. Miles Gilbert (left) chief scientist of the expedition, and Larry Martin, curator of the Dyche Museum of Natural History, sort through a tray of bone fragments trying to "put the puzzle together." Some of the larger pieces that couldn't be matched were sent to a laboratory to be used for carbon dating.
Work in the trap usually ended early in the evening. Members of the expedition spent their free time exploring the two caves in the area, pinckoning on the rim of nearby Devil's canyon or an Indian wrestling match before supper.