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simple teardrop…shaped hand axe； but it was the world鈥檚first piece of advanced technology。
it was so superior to existing tools that soon others were following the inventor鈥檚 lead andmaking hand axes of their own。 eventually whole societies existed that seemed to do littleelse。 鈥渢hey made them in the thousands；鈥潯ays ian tattersall。 鈥渢here are some places inafrica where you literally can鈥檛 move without stepping on them。 it鈥檚 strange because they arequite intensive objects to make。 it was as if they made them for the sheer pleasure of it。鈥�
from a shelf in his sunny workroom tattersall took down an enormous cast； perhaps a footand a half long and eight inches wide at its widest point； and handed it to me。 it was shapedlike a spearhead； but one the size of a stepping…stone。 as a fiberglass cast it weighed only afew ounces； but the original； which was found in tanzania； weighed twenty…five pounds。 鈥渋twas pletely useless as a tool；鈥潯attersall said。 鈥渋t would have taken two people to lift itadequately； and even then it would have been exhausting to try to pound anything with it。鈥�
鈥渨hat was it used for then？鈥�
tattersall gave a genial shrug； pleased at the mystery of it。 鈥渘o idea。 it must have had somesymbolic importance； but we can only guess what。鈥�
the axes became known as acheulean tools； after st。 acheul； a suburb of amiens innorthern france； where the first examples were found in the nineteenth century； and contrastwith the older； simpler tools known as oldowan； originally found at olduvai gorge intanzania。 in older textbooks； oldowan tools are usually shown as blunt； rounded； hand…sizedstones。 in fact； paleoanthropologists now tend to believe that the tool part of oldowan rockswere the pieces flaked off these larger stones； which could then be used for cutting。
now here鈥檚 the mystery。 when early modern humans鈥攖he ones who would eventuallybee us鈥攕tarted to move out of africa something over a hundred thousand years ago；acheulean tools were the technology of choice。 these early homo sapiens loved theiracheulean tools； too。 they carried them vast distances。 sometimes they even took unshapedrocks with them to make into tools later on。 they were； in a word； devoted to the technology。
but although acheulean tools have been found throughout africa； europe； and western andcentral asia； they have almost never been found in the far east。 this is deeply puzzling。
in the 1940s a harvard paleontologist named hallum movius drew something called themovius line； dividing the side with acheulean tools from the one without。 the line runs in asoutheasterly direction across europe and the middle east to the vicinity of modern…daycalcutta and bangladesh。 beyond the movius line； across the whole of southeast asia andinto china； only the older； simpler oldowan tools have been found。 we know that homosapiens went far beyond this point； so why would they carry an advanced and treasured stonetechnology to the edge of the far east and then just abandon it？
鈥渢hat troubled me for a long time；鈥潯ecalls alan thorne of the australian nationaluniversity in canberra。 鈥渢he whole of modern anthropology was built round the idea thathumans came out of africa in two waves鈥攁 first wave of homo erectus； which became javaman and peking man and the like； and a later； more advanced wave of homo sapiens； whichdisplaced the first lot。 yet to accept that you must believe thathomo sapiens got so far withtheir more modern technology and then； for whatever reason； gave it up。 it was all verypuzzling； to say the least。鈥�
as it turned out； there would be a great deal else to be puzzled about； and one of the mostpuzzling findings of all would e from thorne鈥檚 own part of the world； in the outback ofaustralia。 in 1968； a geologist named jim bowler was poking around on a long…dried lakebedcalled mungo in a parched and lonely corner of western new south wales when somethingvery unexpected caught his eye。 sticking out of a crescent…shaped sand ridge of a type knownas a lunette were some human bones。 at the time； it was believed that humans had been inaustralia for no more than 8；000 years； but mungo had been dry for 12；000 years。 so whatwas anyone doing in such an inhospitable place？
the answer； provided by carbon dating； was that the bones鈥櫋wner had lived there whenlake mungo was a much more agreeable habitat； a dozen miles long； full of water and fish；fringed by pleasant groves of casuarina trees。 to everyone鈥檚 astonishment； the bones turnedout to be 23；000 years old。 other bones found nearby were dated to as much as 60；000 years。
this was unexpected to the point of seeming practically impossible。 at no time sincehominids first arose on earth has australia not been an island。 any human beings who arrivedthere must have e by sea； in large enough numbers to start a breeding population； aftercrossing sixty miles or more of open water without having any way of knowing that aconvenient landfall awaited them。 having landed； the mungo people had then found their waymore than two thousand miles inland from australia鈥檚 north coast鈥攖he presumed point ofentry鈥攚hich suggests； according to a report in the proceedings of the national academy ofsciences； 鈥渢hat people may have first arrived substantially earlier than 60；000 years ago。鈥�
how they got there and why they came are questions that can鈥檛 be answered。 according tomost anthropology texts； there鈥檚 no evidence that people could even speak 60；000 years ago；much less engage in the sorts of cooperative efforts necessary to build ocean…worthy craft andcolonize island continents。
鈥渢here鈥檚 just a whole lot we don鈥檛 know about the movements of people before recordedhistory；鈥潯lan thorne told me when i met him in canberra。 鈥渄o you know that whennineteenth…century anthropologists first got to papua new guinea； they found people in thehighlands of the interior； in some of the most inaccessible terrain on earth； growing sweetpotatoes。 sweet potatoes are native to south america。 so how did they get to papua newguinea？ we don鈥檛 know。 don鈥檛 have the faintest idea。 but what is certain is that people havebeen moving around with considerable assuredness for longer than traditionally thought； andalmost certainly sharing genes as well as information。鈥�
the problem； as ever； is the fossil record。 鈥渧ery few parts of the world are even vaguelyamenable to the long…term preservation of human remains；鈥潯ays thorne； a sharp…eyed manwith a white goatee and an intent but friendly manner。 鈥渋f it weren鈥檛 for a few productiveareas like hadar and olduvai in east africa we鈥檇 know frighteningly little。 and when youlook elsewhere； often wedo know frighteningly little。 the whole of india has yielded just oneancient human fossil； from about 300；000 years ago。 between iraq and vietnam鈥攖hat鈥檚 adistance of some 5；000 kilometers鈥攖here have been just two： the one in india and aneandertal in uzbekistan。鈥潯e grinned。 鈥渢hat鈥檚 not a whole hell of a lot to work with。 you鈥檙eleft with the position that you鈥檝e got a few productive areas for human fossils； like the greatrift valley in africa and mungo here in australia； and very little in between。 it鈥檚 notsurprising that paleontologists have trouble connecting the dots。鈥�
the traditional theory to explain human movements鈥攁nd the one still accepted by themajority of people in the field鈥攊s that humans dispersed across eurasia in two waves。 thefirst wave consisted of homo erectus； who left africa remarkably quickly鈥攁lmost as soon asthey emerged as a species鈥攂eginning nearly two million years ago。 over time； as they settledin different regions； these early erects further evolved into distinctive types鈥攊nto java manand peking man in asia； and homo heidelbergensis and finally homo neanderthalensis ineurope。
then； something over a hundred thousand years ago； a smarter； lither species of creature鈥攖he ancestors of every one of us alive today鈥攁rose on the african plains and began radiatingoutward in a second wave。 wherever they went； according to this theory； these new homosapiens displaced their duller； less adept predecessors。 quite how they did this has alwaysbeen a matter of disputation。 no signs of slaughter have ever been found； so most authoritiesbelieve the newer hominids simply outpeted the older ones； though other factors may alsohave contributed。 鈥減erhaps we gave them smallpox；鈥潯uggests tattersall。 鈥渢here鈥檚 no real wayof telling。 the one certainty is that we are here now and they aren鈥檛。鈥�
these first modern humans are surprisingly shadowy。 we know less about ourselves；curiously enough； than about almost any other line of hominids。 it is odd indeed； as tattersallnotes； 鈥渢hat the most recent major event in human evolution鈥攖he emergence of our ownspecies鈥攊s perhaps the most obscure of all。鈥潯obody can even quite agree where trulymodern humans first appear in the fossil record。 many books place their debut at about120；000 years ago in the form of remains found at the klasies river mouth in south africa；but not everyone accepts that these were fully modern people。 tattersall and schwartzmaintain that 鈥渨hether any or all of them actually represent our species st