大名鼎鼎的貴族居維葉在巴黎提出了絕種論。同年——實(shí)際上是同月,在英吉利海峽對岸,一個不大知名的英國人在發(fā)表對化石價值的見解。他的見解也具有持久的影響。威廉·史密斯是薩默塞特的科爾運(yùn)河建筑工地上的年輕監(jiān)督員。1796年1月5日,他坐在薩默塞特一家馬車旅店里,記下了那個最終會使他名揚(yáng)天下的觀點(diǎn)。
To interpret rocks, there needs to be some means of correlation, a basis on which you can tellthat 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 stratacertain species of fossils disappeared while others carried on into subsequent levels. By notingwhich species appeared in which strata, you could work out the relative ages of rocks whereverthey appeared.
若要解釋巖石,你非得有某種并置對比的東西。在這個基礎(chǔ)上,你可以知道德文的那些石炭紀(jì)巖石要比威爾士的這些寒武紀(jì)巖石年輕。史密斯的見解都基于化石之上。隨著巖層的每一變化,有的物種的化石消失了,而有的化石一直延伸到隨后的巖層。通過發(fā)現(xiàn)哪種物種在哪個巖層出現(xiàn),你就可以計算出巖石的年齡,無論這些巖石是在哪里。
Drawing on his knowledge as a surveyor, Smith began at once to make a map of Britain's rockstrata, which would be published after many trials in 1815 and would become a cornerstone ofmodern geology. (The story is comprehensively covered in Simon Winchester's popular bookThe Map That Changed the World .)
憑著他作為測量員所擁有的知識,史密斯馬上動手繪制英國的巖層圖。經(jīng)過多次試用以后,這些圖于1815年出版,成為近代地質(zhì)學(xué)的奠基石。(西蒙·溫切斯特在他深受歡迎的《改變世界的地圖》一書里對這件事作了全面的記述。