In the same year—in fact, the same month—that the aristocratic and celebrated Cuvier was propounding his extinction theories in Paris, on the other side of the English Channel a rather more obscure Englishman was having an insight into the value of fossils that would also have lasting ramifications. William Smith was a young supervisor of construction on the Somerset Coal Canal. On the evening of January 5, 1796, he was sitting in a coaching inn in Somerset when he jotted down the notion that would eventually make his reputation.

大名鼎鼎的贵族居维叶在巴黎提出了绝种论。同年——实际上是同月，在英吉利海峡对岸，一个不大知名的英国人在发表对化石价值的见解。他的见解也具有持久的影响。威廉·史密斯是萨默塞特的科尔运河建筑工地上的年轻监督员。1796年1月5日，他坐在萨默塞特一家马车旅店里，记下了那个最终会使他名扬天下的观点。

To interpret rocks, there needs to be some means of correlation, a basis on which you can tell that those carboniferous rocks from Devon are younger than these Cambrian rocks from Wales. Smith's insight was to realize that the answer lay with fossils. At every change in rock strata certain species of fossils disappeared while others carried on into subsequent levels. By noting which species appeared in which strata, you could work out the relative ages of rocks wherever they appeared.

若要解释岩石，你非得有某种并置对比的东西。在这个基础上，你可以知道德文的那些石炭纪岩石要比威尔士的这些寒武纪岩石年轻。史密斯的见解都基于化石之上。随着岩层的每一变化，有的物种的化石消失了，而有的化石一直延伸到随后的岩层。通过发现哪种物种在哪个岩层出现，你就可以计算出岩石的年龄，无论这些岩石是在哪里。

Drawing on his knowledge as a surveyor, Smith began at once to make a map of Britain's rock strata, which would be published after many trials in 1815 and would become a cornerstone of modern geology. (The story is comprehensively covered in Simon Winchester's popular book The Map That Changed the World .)

凭着他作为测量员所拥有的知识，史密斯马上动手绘制英国的岩层图。经过多次试用以后，这些图于1815年出版，成为近代地质学的奠基石。（西蒙·温切斯特在他深受欢迎的《改变世界的地图》一书里对这件事作了全面的记述。