In 1769 in a little town in Oxfordshire, England, a child with the very ordinary name of William Smith was born into the poor family of a village blacksmith. He received rudimentary village schooling, but mostly he roamed his uncle's farm collecting the fossils that were so abundant in the rocks of the Cotswold hills. When he grew older, William Smith taught himself surveying from books he bought with his small savings, and at the age of eighteen he was apprenticed to a surveyor of the local parish. He then proceeded to teach himself geology, and when he was twenty-four, he went to work for the company that was excavating the Somerset Coal Canal in the south of England.
This was before the steam locomotive, and canal building was at its height. The companies building the canals to transport coal needed surveyors to help them find the coal deposits worth mining as well as to determine the best courses for the canals. This job gave Smith an opportunity to study the fresh rock outcrops created by the newly dug canal. He later worked on similar jobs across the length and breadth of England, all the while studying the newly revealed strata and collecting all the fossils he could find. Smith used mail coaches to travel as much as 10,000 miles per year. In 1815 he published the first modern geological map, “A Map of the Strata of England and Wales with a Part of Scotland,” a map so meticulously researched that it can still be used today.
In 1831 when Smith was finally recognized by the Geological Society of London as the “father of English geology,” it was not only for his maps but also for something even more important. Ever since people had begun to catalog the strata in particular outcrops, there had been the hope that these could somehow be used to calculate geological time. But as more and more accumulations of strata were cataloged in more and more places, it became clear that the sequences of rocks sometimes differed from region to region and that no rock type was ever going to become a reliable time marker throughout the world. Even without the problem of regional differences, rocks present a difficulty as unique time markers. Quartz is quartz—a silicon ion surrounded by four oxygen ions—there’s no difference at all between two-million-year-old Pleistocene quartz and Cambrian quartz created over 500 million years ago.
As he collected fossils from strata throughout England, Smith began to see that the fossils told a different story from the rocks. Particularly in the younger strata, the rocks were often so similar that he had trouble distinguishing the strata, but he never had trouble telling the fossils apart. While rock between two consistent strata might in one place be shale and in another sandstone, the fossils in that shale or sandstone were always the same. Some fossils endured through so many millions of years that they appear in many strata, but others occur only in a few strata, and a few species had their births and extinctions within one particular stratum. Fossils are thus identifying markers for particular periods in Earth's history.
Not only could Smith identify rock strata by the fossils they contained, he could also see a pattern emerging: certain fossils always appear in more ancient sediments, while others begin to be seen as the strata become more recent. By following the fossils, Smith was able to put all the strata of England's earth into relative temporal sequence. About the same time, Georges Cuvier made the same discovery while studying the rocks around Paris.
Soon it was realized that this principle of faunal (animal) succession was valid not only in England or France but virtually everywhere. It was actually a principle of floral succession as well, because plants showed the same transformation through time as did fauna. Limestone may be found in the Cambrian or—300 million years later—in the Jurassic strata, but a trilobite—the ubiquitous marine arthropod that had its birth in the Cambrian—will never be found in Jurassic strata, nor a dinosaur in the Cambrian.
英国牛津郡的小镇在 1769 年与威廉史密斯非常普通的名称孩子出生于贫穷的家庭的铁匠。他收到简陋的乡村学校教育,但主要是他漫游他叔叔的农场收集了如此丰富的科茨沃尔德丘陵岩石中的化石。当他长大了时,威廉史密斯自学测量从他买了小积蓄和年龄十八岁师从当地教区的验船师的书。接着,他自学地质,和当他是二十四,他去在开挖在英格兰南部的萨默塞特煤运河在公司上班。这是在蒸汽机之前,运河建造正处于它的高度。公司建造运河运输煤炭需要测量师来帮助他们找到煤矿开采价值,确定的运河的最佳路线。这份工作给了史密斯有机会去学习新鲜的岩石露头由新挖运河。他后来类似的工作跨长度和宽度的英格兰,都在学习新的地层和收集所有他能找到的化石。史密斯曾经邮件教练旅行每年高达 1 万英里。1815 年他出版了第一次现代地质地图,"地图的地层的英格兰和威尔士的部分的苏格兰,"所以精心研制,它仍可使用今天。在 1831 年当史密斯最后被承认的伦敦地质学会为"英国地质学之父",它是不仅为他的地图,甚至更重要的东西。自从人们开始目录中特定露头地层,一直希望这些某种程度上可以用来计算地质年代。但随着越来越多积累的地层被编录在越来越多的地方,很明显,岩石的序列有时不同从一个地区到另一个地区和没有岩石类型曾经打算成为一个可靠的时间标记在世界各地。即使没有差异问题的区域,岩石目前作为独特的时间标记的一个难点。石英是石英 — — 四个氧离子包围的硅离子 — — 200 万岁更新世石英和创建在 5 亿多年前的寒武纪石英之间根本就没有区别。As he collected fossils from strata throughout England, Smith began to see that the fossils told a different story from the rocks. Particularly in the younger strata, the rocks were often so similar that he had trouble distinguishing the strata, but he never had trouble telling the fossils apart. While rock between two consistent strata might in one place be shale and in another sandstone, the fossils in that shale or sandstone were always the same. Some fossils endured through so many millions of years that they appear in many strata, but others occur only in a few strata, and a few species had their births and extinctions within one particular stratum. Fossils are thus identifying markers for particular periods in Earth's history.Not only could Smith identify rock strata by the fossils they contained, he could also see a pattern emerging: certain fossils always appear in more ancient sediments, while others begin to be seen as the strata become more recent. By following the fossils, Smith was able to put all the strata of England's earth into relative temporal sequence. About the same time, Georges Cuvier made the same discovery while studying the rocks around Paris. 很快它实现了这一原则的动物 (动物) 的演替是有效的不仅在英国或法国几乎是无处不在。其实花继承以及原则,因为植物显示具有相同的变换,通过时间作为做动物区系。石灰石可发现在寒武纪或 — — 3 亿年后 — — 中侏罗世地层,但三叶虫 — — 无处不在的海生节肢动物,它的诞生在寒武系 — — 永远不会发现在侏罗系地层,也不是一只恐龙在寒武系。
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