Instead what we would see if we crunched up the rock and examined it microscopically would be the chemical residues that the organisms left behind, 要是我们把岩石敲碎，放在显微镜下面细看，只会看到微生物残留的化学物质，

　　carbon isotopes and a type of phosphate called apatite, which together provide strong evidence that the rock once contained colonies of living things. 碳同位素以及一种名叫磷灰石的磷酸盐。二者一块儿表明，那块岩石里过去存在过生物的小天地。

　　"We can only guess what the organism might have looked like," Bennett said. “至于那些生物是什么模样的，我们只能猜猜而已，”贝内特说，

　　"It was probably about as basic as life can get——but it was life nonetheless. It lived. It propagated." “它很可能是最基本生命——不过，它毕竟也是生命。它活过。它繁殖过。”

　　And eventually it led to us. 最后，就到了我们这一代。

　　If you are into very old rocks, and Bennett indubitably is, the ANU has long been a prime place to be. 要是你打算钻进非常古老的岩石——贝内特女士无疑是这么做的，澳大利亚国立大学长期以来是个首选去处。

　　This is largely thanks to the ingenuity of a man named Bill Compston, 这在很大程度上要归因于一位名叫比尔·康普斯顿的足智多谋的人。

　　who is now retired but in the 1970s built the world's first Sensitive High Resolution Ion Micro Probe, 他现在已经退休，但在20世纪70年代建立了世界上第一台“灵敏高清晰离子显微探测器”，

　　or SHRIMP, as it is more affectionately known from its initial letters. 或者以它的开头字母更亲昵地被称之为小虾。

　　This is a machine that measures the decay rate of uranium in tiny minerals called zircons. 这种仪器用来测定名叫锆石的微小矿石里铀的衰变率。

　　Zircons appear in most rocks apart from basalts and are extremely durable, surviving every natural process but subduction. 锆石存在于除玄武岩以外援大多数岩石，寿命极长，能够挺过除潜没以外的任何自然过程。

　　Most of the Earth's crust has been slipped back into the oven at some point, 绝大部分地壳已经在某个时刻滑回地球内部，

　　but just occasionally—in Western Australia and Greenland, for example—geologists have found outcrops of rocks that have remained always at the surface. 但偶尔——比如在澳大利亚西部和格陵兰——地质学家们会发现始终留在地表的岩石。