National Geographic : 1981 Apr
value. They may also be found by people seeing fossils in the natural state for the first and only time. It could be the highlight of their vacation." Descendants of the Badlands' prehistoric horses and camels, American originals, emi grated to the Old World over the Bering land bridge millions of years ago. They used the same route by which deer and other big game had arrived in the New World millions of years earlier. When horses finally re turned-thanks to the conquistadores- after an absence of 10,000 years, the region teemed with large mammals. There were deer, elk and bison, pronghorn antelope, black and grizzly bears, gray wolves, coyotes, cougars, and bighorn sheep. This primitive abundance ended with the finding of gold in the Black Hills. Adventur ers swarmed into the region. And since ad venturing is hungry work, especially with pick and shovel, there was great demand for fresh meat. Elk and bison were gone by the 1890s, and bighorn sheep and pronghorn outpourings of mud from the nearby Black Hills and volcanic ash from the then young Rocky Mountains preserved the bones of hundreds of now extinct species. With a dentist's drill (above) an associateof Dr. Bjork frees from its mudstone tomb a skull of Mesohippus, a collie-size ancestorof today's horse. NationalGeographic Society research grants support such work. Tortoiseshells are continually unearthed (right)by the eroding wind and rain. More than a cemetery, the Badlands today provide sanctuaryfor pronghorn antelope (facingpage), bison, prairie dogs, and a profusion of other wildlife.