National Geographic : 1973 Jun
Hunting ground of prehistory, AFRICA the site that yielded the "1470" $ skull (above) wears a rubbed raw look. Scientists used sieves as fine as mosquito netting to recover the tiniest fragments of bone. Waters of Lake Rudolf-now 10 miles distant-once lapped these shores, leaving the sediments that encased and fossilized the remains of "1470 man" and his smaller brained contemporary, Australopithecus. Massive forces in Africa's quake-prone Great Rift Valley system fractured the base rock and set it atilt (right), accelerating the erosion that laid bare the fossil-rich sedi mentary level yielding "1470 man." Still deeper layers promise further major discoveries on mankind's fossil trail.