Man Traced 3.75 Million Years By Fossils Found in Tanzania
Dr Mary Leakey announces discovery of fossil evidence, made up of jaws and teeth of at least 11 creatures, showing that man evolved and lived in E Africa almost 3.75-million yrs ago, nearly 1-million yrs earlier than had been previously established, Washington (DC) news conf convened by Natl Geographic Soc; new evidence reptdly is oldest reliably dated examples of true man; fossils, found in Laetolil region 25 mi south of Olduvai Gorge where Leakey team has made many discoveries over last 2 decades, were dated by Calif Univ (Berkeley) scientist Dr Garniss H Curtis; previous oldest reliably dated hominid, discoveries made by Dr Donald Carl Johanson in Ethiopia and Richard Leakey in Kenya, are no more than 3-million yrs old; Mary Leakey says new fossils, which share many anatomic features with younger homo fossils, represent species that is clearly different from Australopithecus and are of same species as Richard Leakey's '1470 man'; says powerful evidence now shows that human lineage has been separate and evolving toward its present stage for very long time; new discoveries reptdly confirm view that Australopithecus until recently thought to be ancestor of modern man, was offshoot of hominid line that died out; Leakey por (M)