Funding for Klehm's research on the pillar site stone beads was provided by the Wenner-Gren Foundation. On the shores of Lake Turkana in east Africa, about 5,000 to 4,000 years ago, pastoralists ...

A clump of grass grows on an outcrop of shale 33,000 years ago. An ostrich pecks at the grass, and atoms taken up from the shale and into the grass become part of the eggshell the ostrich lays. A ...