IN THE SUMMER of 1971, a young geologist named Mike Voorhies was scouting around onsome grassy farmland iern Nebraska, not far from the little town of Orchard, where hehad grown up. Passing through a steep-sided gully, he spotted a curious glint in the brushabove and clambered up to have a look. What he had seen was the perfectly preserved skull ofa young rhinoceros, which had been washed out by ret heavy rains.
A few yards beyond, it turned out, was one of the most extraordinary fossil beds everdiscovered in North America, a dried-up water hole that had served as a mass grave for scoresof animals—rhinoceroses, zebra-like horses, saber-toothed deer, camels, turtles. All had diedfrom some mysterious cataclysm just uwelve million years ago iime known togeology as the Mioe. In those days Nebraska stood on a vast, hot plain very like theSerei of Africa today. The animals had been found buried under volic ash up to te deep. The puzzle of it was that there were not, and never had been, any voloes inNebraska.
Today, the site of Voorhies』s discovery is called Ashfall Fossil Beds State Park, and it has astylish new visitors』 ter and museum, with thoughtful displays on the geology of Nebraskaand the history of the fossil beds. The ter incorporates a lab with a glass wall throughwhich visitors watch paleontologists ing bones. W alone in the lab on them I passed through was a cheerfully grizzled-looking fellow in a blue work shirt whnized as Mike Voorhies from a BBC television dotary in which he featured.
They don』t get a huge number of visitors to Ashfall Fossil Beds State Park—it』s slightly inthe middle of nowhere—and Voorhies seemed pleased to show me around. He took me to thespot atop a twenty-foot ravine where he had made his find.
「It was a dumb place to look for bones,」 he said happily. 「But I wasn』t looking for bones. Iwas thinking of making a geological map of eastern Nebraska at the time, and really just kindof poking around. If I hadn』t gone up this ravine or the rains hadn』t just washed out that skull,I』d have walked on by and this would never have been found.」 He indicated a roofedenclosure nearby, which had bee the main excavation site. Some two hundred animalshad been found lying together in a jumble.
I asked him in what way it was a dumb place to hunt for bones. 「Well, if you』re looking forbones, you really need exposed rock. That』s why most paleontology is done in hot, dry places.
It』s not that there are more bohere. It』s just that you have some ce of spotting them.
In a setting like this」—he made a sweepiure across the vast and unvarying prairie—「you wouldn』t know where to begin. There could be really magnifit stuff out there, butthere』s no surface clues to show you where to start looking.」
At first they thought the animals were buried alive, and Voorhies stated as mu aNational Geographic article in 1981. 「The article called the site a 『Pompeii of prehistoriimals,』 」 he told me, 「which was unfortunate because just afterward we realized that theanimals hadn』t died suddenly at all. They were all suffering from something calledhypertrophic pulmonary osteodystrophy, which is what you would get if you were breathing alot of abrasive ash—and they must have beehing a lot of it because the ash was feetthick for hundreds of miles.」 He picked up a k of grayish, claylike dirt and crumbled itinto my hand. It owdery but slightly gritty. 「Nasty stuff to have to breathe,」 he went on,「because i