National Geographic : 2004 Apr
LIVING FOSSIL A western painted turtle crawls over a parched land, which bears the bones of its ancestors. The park is known for itsfossils, especially those of early mammals often more than 30 million years old. geo-caching," says L6pez. In this latest twist to a treasure hunt, people hide a container and perhaps a trinket, take the GPS coordinates, and put the coordinates on the Internet. Other people go to the location and try to find the cache. Although a treasure hunt may seem a nuisance at worst, and can have the positive effect of getting people out in nature, L6pez warns of an escalation: Some geo-cachers are finding fossils in park rocks and put ting those coordinates on the Web. Anyone can then come to look or to take. "To us, a shovel is a shovel" says Benton. "Digging up anything here is illegal." Her mental radar always on, Benton notices every vehicle parked on the roadside and scans for people carrying trowels and large packs. While something can be done about fossil theft, little can be done about the other, natural, processes that damage fossils-wind and water erosion. Pointing to the Wall near Cedar Pass, Benton explains: The Badlands formation consists mostly of claystone, hundreds of feet thick, that washed down from the Black Hills to the west between 37 and 25 million years ago. Yet the sculpting of the Badlands began a mere 500,000 years ago, an eyeblink of geologic time. "That's when the Cheyenne, the White, and the Bad River systems began to flow over all that clay sediment and carve the Wall;' Benton says. "And at the present rate of erosion, this will all be gone in another half million years." Long before that, of course, countless fossils will be washed away. Water and wind continue to carve the Badlands, claiming up to an inch or more in some places each year. "Probably an oreodont," Benton says as we walk along a butte and she spots a fist-size skull protruding from the bank. "We find them through out the park. Sheeplike mammals that lived in herds about 30 million years ago." The fossil lies intact in the soil, but Benton knows other eyes are searching for such a find. Back in the car, we round a bend. "Stop," she says. "I want to check out that van." BADLANDS NATIONAL PARK 91 GET LOST IN THE BADLANDS Find out how to get there, what to see and do, and where to stay in our Online Extra at nationalgeographic.com/magazine/0404.