Natural Trap Cave, Big Horn Mountains, Wyoming

In the Pleistocene Epoch, thousands of mammals fell into this cave, an 85-foot-deep karst limestone sinkhole on the western slope of the Big Horn Mountains in north-central Wyoming. Larry Martin, a vertebrate paleontologist from the University of Kansas, was one of the scientists leading this dig in the mid-1970s. Among the more than 30,000 specimens recovered were the bones from animals now extinct, such as mammoths, camels, American lions, woodland musk oxen, cheetahs, dire wolves, short-faced bears and four kinds of horses.
The dining tent at Armpit Camp was the gathering spot for lectures, meals, job assignments and for work on sorting the vast number of tiny bones from the dig.

Larry Martin, in a hard hat, digs in a pit in the Natural Trap.