A cave in Wyoming that's easy to fall into, and hard to escape, has become a treasure trove for scientists. Scientists excavating an ancient Wyoming sinkhole containing a rare trove of fossils of Ice Age mammals have unearthed hundreds of bones of such prehistoric animals as American cheetahs, a paleontologist said on Friday. The two-week dig by an international team of researchers led by Des Moines University paleontologist Julie Meachen marked the first exploration of Natural Trap Cave at the base of the Bighorn Mountains in north-central Wyoming since its initial discovery in the 1970s. ... Meachen said the extensive excavation that began late last month uncovered roughly 200 large bones of animals like horses that roamed North America from 12,000 to 23,000 years ago and an uncounted number of microfossils of creatures such as birds, lizards and snakes. ... A number of animals that fell 85 feet to their deaths after stumbling into the 15-foot-wide mouth of the cavern were unusually well preserved by cold and damp conditions, Meachen said.