Ice Age in NebraskaAmong the many discoveries of these Niobrara expeditions
was something NOT reported in the official records.
It was found when the archeologists dug down to excavate a cache pit -- that's a hole dug into the ground, inside a dwelling, then lined with rocks and clay, and used to store food for future use. Not exactly a modern refrigerator, but the ground is cool even in the Summer and a cover usually keeps the rodents out.
As they were digging out the bottom layers around the cache pit, one of the workers notices an oddly-shaped rock in the dirt underneath and called it to the attention of the supervisors (my father and Alexis Praus). Upon examination, it turned out to be a bone, but it obviously was NOT a Ponca bone. It was well below the floor of the dwelling, in layers of sediment that were deposited BEFORE the end of the Ice Age -- a few thousand years earlier. They took pictures of the layers of earth, to show that it was found "in situ", then cleaned off the bone and labeled it. It was part of a skull, but the thick brow ridges and shallow slope of the forehead was more like a primitive Neanderthal, rather than the modern humans who had crossed the Bering Straits AFTER the end of the Ice Age.
However, this evidence was at variance with the "accepted" theories, that no humans were in North America before the end of the Ice Age (about 10,000 years ago). Dr. Ales Hrdlick, a staunch proponent of the "accepted" chronology (and very-influential authority in the field), objected strongly to the inclusion of this item in the reports. Refusing to even look at the photographs showing that the skull bone was found "in situ" (with the soil layers intact above it), he insisted that it must have been a "burial by intrusion" should be classified as a "throwback"(or mutation). Prof. Bell agreed to leave it out of the reports, publishing a description in a separate paper, with no reference to the Niobrara excavations. 
POSTSCRIPTIn recent times, there has been new evidence that, indeed, confirms human presence of in North America before the glacial maximum. ,